The Science of Human Potential

Why beans could make you fat…and cheese won’t


This post is about how different people react, metabolically, to different foods, especially carbohydrates.  How you personally respond to dietary carbohydrate should help you make some decisions about what and how you eat.

It gets scientific but the science is important.

Several researchers have tried to quantify how we process different types of carbs.  These include the glycemic index, the glycemic load and the less known insulin index.  These are all really interesting and occasionally useful to tell an individual about how rapidly the carbs they consume are likely to be absorbed into their body and the possible glycemic and insulin response.

The insulin index, in particular, offers some promise. The insulin index quantifies the typical insulin response to various foods. That’s great because that’s what’s we are particularly interested in; our insulin response to foods.

The alternative hypothesis (also known as the carbohydrate theory of obesity) suggests that high levels of insulin are responsible for us getting fat. I think this alternative hypothesis should be the default one as the most likely mechanism of obesity.  I’m basing this on the available evidence and logic through evolutionary biology.  This means that the insulin index, in particular, offers some promise. The insulin index quantifies the typical insulin response to various foods and shows some foods will cause more insulin to be released than other foods.

The trouble is that the Index is based on the average effect of particular foods on metabolically functional (insulin sensitive) humans, not the specific effect on a given individual.  I’m not alone in thinking that individuals vary enormously in their ability to move carbohydrates out of their blood stream into cells.  The cells might be muscle, other body, or fat cells.  It all depends on your genetics, your age, and your personal eating and exercise history. In other words, depending on who you are and how you have treated your body, you will respond very differently to the same load of carbs.

This is nothing new of course. That is the whole point of the Oral Glucose Tolerance test.  You drink 75g of pure glucose and we monitor your glucose response over time. More insulin sensitive people will clear the glucose load more quickly. Although not normally measured, we know the area under the insulin curve will be less in these people. Less insulin = more fat burning, less fat storage and a greater propensity to move and exercise.

So what about other foods and how we react to them? The conventional advice is to eat more carbohydrates with fibre, especially plant fibre. These are released into the blood stream more slowly. This provokes a much smaller glucose and insulin response, thus the insulin resistant cells of metabolically dysfunctional (insulin resistant) people can much more easily deal with the reduced load, even if the total amount of carbs eaten is the same.

That’s why our dietary guidelines at least warn us away from refined (no fibre) dietary carbs and steer us toward “healthy whole grains” and “fibrous” (non-starchy) vegetables. Legumes (beans) are a good example of this. They are absorbed much more slowly.

But what if for some people, like those with Type 2 Diabetes, slow digestion simply means high insulin for a longer time? These people have insulin resistant cells. To get any carbs into the cells, insulin might have to be really high.  Legumes may not be as bad as pure glucose in causing a high insulin response, but the response may be high compared to someone who is insulin sensitive. So beans might just add to the metabolic problems and make them fatter.

So what we should do is feed people a range of different carbohydrate-rich food; from glucose to beans and other things in between. We should measure their glucose and insulin responses before they eat, and for several hours afterwards.

The questions are:

  1. How much does the individual’s area under the glucose and insulin curves vary for different foods?
  2. How much do the absolute amounts of insulin secreted vary between individuals?
  3. How do the insulin curves for the simplest carbs for the most insulin sensitive, compare with the most complex carbs for the least insulin sensitive? Could it be possible that beans provoke a glucose-like response in some, but hey, it just lasts longer in some people?

For me, the idea was planted after a conversation with well-known and highly respected nutrition expert and endocrinologist, and a mentor to me, Professor Jim Mann. For those of you who don’t know this guy, he is simply a legend in New Zealand public health medicine.  His contribution has been and is massive. He is clearly way more experienced than I am in public health nutrition. I have a huge respect for his knowledge, and a readiness to learn from him, but also I hope to generate some healthy debate at the same time.

Anyway, our conversation around carb metabolism was a little bit awkward.  After all, Jim really goes for the “plenty of plant-based carbs, low saturated fat, lean protein” diet.  To be fair, he certainly promotes the importance of at least some fats.  Anyway, despite some differences in the starting hypothesis, what I think I finally got down to was Jim’s assertion that “more complex carbohydrates, like legumes, are digested in the small bowel and have been shown to have lower glycemic and insulin responses”.

Fair enough. I just don’t know that much about beans.

So Catherine Crofts (a doctoral student) and I planned a study to test this. We want to know if high loads of carbohydrate are OK  as long as they are absorbed slowly?  It will hopefully allow us to understand more clearly how individuals could be metabolically profiled, at least for their response to carbs of different sorts.

Of course, any scientist starts by reviewing the literature in the field. And so be it. Talk about having to hunt for research papers.  Catherine, also a pharmacist sick of handing out diabetes medication, has been an absolute legend at digging up research papers on carbohydrate metabolism.  I think she had reviewed some 1600 papers at last count.

Then she found this little cracker from 1989, only cited 18 times since. These citations all, in my view, incorrectly cite what the original researchers actually found. People citing this paper all claim that the glycemic response to beans is so good in diabetics that we should all start eating more beans (the data shows the opposite in fact).

The paper is by Indian researchers Viswanathan et al, in Nutrition Reports International (1989) titled “Responses To Legumes In Niddm Subjects: Lower Plasma Glucose And Higher Insulin Levels.”

The blood glucose and corresponding insulin responses to five different isocaloric (300 kcal) legume preparations were assessed, along with 75 g of glucose (also 300 kcal). They concluded “..the study indicates that the legume preparations are useful in the management of diabetes on account of the lower glycaemic and higher insulin responses produced. The factors responsible for these changes need to be evaluated in greater detail.” 

OK, fair enough, except for a few things:

  1. Their data (see figure below) shows the glucose (top panels) and insulin responses (bottom panels) for healthy controls (left panels) and type 2 diabetics (right panels). The glucose units are not matched on the upper panels – they show that the glucose response to BOTH legumes and glucose is much higher in the diabetics.
  2. The area under the insulin curve for the legumes is comparable to that for glucose for the diabetics.
  3. The insulin curve for the legume-fed diabetics is high and still high at the conclusion of measurement at 2 hours. Also, the insulin curve for glucose and one of the lentils is still climbing!

On the basis of these data, I think we have a case for our study and questioning why we would expose people with insulin resistance to large loads of carbohydrate ever. Surely the logic is faulty?  It is as I see it, faulty logic because while some carbs do get absorbed more slowly from the intestines into the bloodstream, the cells still need large amounts of insulin to get the glucose into the cells.

Insulin is a metabolically useful hormone, but chronic hyperinsulinamia (insulin is high all the time) isn’t good for you.

Promoting even “healthy carbs” in larger loads may not be good for the most metabolically vulnerable. They raise insulin, they raise it high, and for a long time. That’s a poor combination because fat burning is off, and fat storage is on, for a long time.  Something a little more metabolically benign, say cheese, although higher in calories, won’t stuff your hormonal energy regulation up nearly as much.

Eaten on their own, beans could make you fat. Cheese, well we still need to look at how insulin responses vary.  Cheese has zero carbs, some protein and some fat. We probably do get a smaller and shorter insulin response to the protein in  cheese. We should test cheese!



Thanks to Helen Kilding, Catherine Crofts, and Mikki Williden in writing this post

Paradise lost, paradise found. A tale of health in the South and North Pacific

The untouched (and healthy) paradise of Southern Vanuatu

Traditional village life still exists somewhere in the world – Anetytum, Vanuatu

I’ve been lucky enough to contract to the World Health Organization in the South and North Pacific to take on work in the daunting area of non-communicable disease (NCD) prevention (obesity, diabetes, heart disease, etc). It’s been a privilege, but a task which has no easy solution.  Here’s a tale of paradise and paradise lost.  The two extremes of what I’ve seen in the Pacific.

The happiest place in the world?

Aneityum is a small island in Southern Vanuatu. It has several villages, each with its own chief and leadership structure. There are no roads, no cars and no electricity. Almost all of the food is grown locally or caught in the sea. There is a growing, but very small, local tourism operation; some cruise ships stop by for a visit, but they are confined to a smaller island, which the locals have given the tourist-friendly name of Mystery Island. So their sole income is from a small amount of tourism. Money is really only needed for education purposes, i.e. for children going to high school on Tanna, the biggest nearby island. There are both English and French schools on the island. Money is also needed for a small amount of clothing. Everyone has moved on from grass skirts and the like and wears Western-style shorts and T-shirts. One of the first things I saw when I arrived was an All Blacks hat. I’m not sure the guy who was wearing it had heard of the All Blacks, though!

The staple diet on Aneityum comprises fruits, vegetables, water, fish, coconut everything and an occasional small amount of imported rice. In terms of exercise, their system of community subsistence agriculture keeps them active all day. We walked four hours to the next village and back in a single day. Here, this is normal activity.

Do they suffer from lifestyle diseases? Very, very little! They’re primarily concerned with other health care, though they are pretty well organised with this, with a dispensary led by a local who is trained in nursing and other aspects of practical health care.

This is paradise found. Real food, real people, and real happiness. These are the happiest people I have ever met. Do they have problems? Yes, of course. Are they healthy specimens? Pretty much. Do they feel they are missing out on something in life? Absolutely not. Would they eat takeaways and sugary drinks if they could get their hands on them? You bet.

Do these people get diabetes easily when exposed to the industrial food diet?  Yes, Port Villa, Vanuatu’s capital, is just starting to see the rise of the pandemic there.  I just hope and pray that these guys stay as they are.


Happy, healthy kids. Two French speaking little boys give us the thumbs up!


A catch of flying fish and sea salmon.  Just paddle your canoe out at night.  Put your lantern on and the fish all leap into the boat.  When it’s full, paddle in.  Simple as that!

Time bomb: Kiribati


The sad state of Kiribati. Under-nourished kids play on the rubbish in front of a polluted lagoon. Underweight kids and obese adults with diabetes.  If it’s calories in/calories out then are the adults too greedy and eating all the food? I don’t think so.  This is why “the experts” need to travel and see this stuff for themselves.  

Tarawa is the main island in the Republic of Kiribati (formerly the Gilbert Islands). It is right on the equator, about three hours flight north of Fiji, and is famous for the Battle of Tarawa in World War II, in which the US and Japanese smacked it out with huge losses on both sides. You can still see some of the wreckage. A coral atoll, with a maximum height above sea level of 2 m, the island may well cease to exist in a few decades because of global warming. It’s hard to grow food on a coral atoll, and local food supply is a massive issue for the 42,000 people who live on Tarawa, which measures just 40 km long and 300 m wide. Fishing is good (offshore at least), although the influx of foreign aid has meant that a lot of people no longer fish. In any case, the main lagoon is polluted to the extent that there is no inshore fishing or swimming possible.

This is pretty much the opposite of Southern Vanuatu. Staple foods are cheap imported products such as soft drinks, white rice, flour, sugar, tinned fish and instant noodles. We saw diabetes running at 60 per cent, the highest I have ever heard of. Out of hundreds of people that I measured, I think only one or two were not obese. There is a road that runs the length of the island and everyone rides in a car or minibus. Habitual walking and manual work have decreased.

The net result in Tarawa is paradise lost. Rubbish everywhere, NCDs out of control, with no solutions in sight. I measured the blood-sugar levels of everyone in my local health team. They all had diabetes.  Fasting blood glucose was over 10  mmol/L for everyone.  Remember normal is under 5.

The physiotherapy department at the hospital only deals with amputees from diabetes complications. That’s running between 5 and 15 a month.

Two islands in the beautiful Pacific. One on real food and a traditional lifestyle, the other on the cheapest energy available: processed carbohydrates. If you ever wanted evidence that processed carbohydrates damage humans, you should go to Kiribati and have a look for yourself.

Here we have the perverse and real situation that  there are obese adults and undernourished kids in the same family. That’s what you get on a high simple carb diet. Its wrong and it’s not the fault of these guys. what do you think is happening here?  Are the parents eating all the food and starving the kids?  Of course not.  It’s metabolic dysfunction from the carbs running riot.

I wrote this post because it was a turning point for me in understanding that it was nothing to do with calories in and calories out. It is metabolic and hormonal control.  It’s fairly clear to me.

More pictures to give you a flavour of what we saw in the “Happiest place in the world”. The only dodgy thing in these places are the toilets, especially at night.


Sunset on Aniwa in Southern Vanuatu


The island’s health committee shows off their health monitoring techniques


Sunday village lunch after church at Futuna Island.  Health checks conducted after service but before lunch. Real food is all you can get here!


I wanted to have a caption saying “Grant Schofield picking up a chick!”


No caption needed


A day’s physical activity on the island


Where else in the world can you walk up to the edge of an active volcano and breathe in poisonous gases. dodge flying lava, and all this with no health and safety regulations?! Tana Island


This was, no kidding, someone’s carry on baggage on a local flight! You slip your fingers under the gills to hold it as you walk on.


Lean, strong, and healthy in Vanuatu

What do I actually eat?


Grant Schofield has a chat to a village pig about the pig’s future. The pig listens carefully.

Thanks to everyone who has started following this blog.  Frankly, while I find this stuff interesting and important, I had no idea that it was shared by so many other people.  An academic’s real-life exposure to social media is an eye opener and fun. 3000 hits in a little over a week!

So the main question I have had from people so far is “what do you eat?” and “what about kids?” I think I can talk about both of those, in this and the next post. After all I am me, and I am the father of three boys.

Some background:

I have been active and relatively fit my whole life, including a stint as a professional triathlete. One observation and my main excuse for not being a long lasting and super duper fast professional triathlete, was that I could never get my weight under 85-86 kg.  In fact, when I did my fastest time in Ironman NZ 2001, I was officially entered in the heavy weight “clydesdale” division, where I was 94 kg at weigh in. To be fair, that was at the conclusion of the pre-race pasta party. My time of 9:04 was (I claimed at least), at the time, a clydesdale world record.  I’m not sure there is such a record but it gave me mileage at the time – “world’s fastest fat guy over the Ironman triathlon distance”.

What bugged me though was why I couldn’t get fully race lean. I was eating low fat, high carb.  It was exactly what the experts said I should do.  I could hardly exercise any more.  I was training up to 25 hours a week! In fact, I noticed the same thing when I watched the Ironman in Taupo New Zealand  this year.  Roughly one third of the field is overweight or obese in my judgement.  How can they stay fat doing so much exercise?  Maybe they are LESS fat than when they started?  Or maybe their high carb diet and chronically raised insulin fails to allow fat burning?

Anyway, post triathlon retirement and children arriving I was up over 102 kg.  I was still exercising everyday, eating “healthily” and still fatter than ever and it was getting out of control.  Why was I always hungry? Why did my energy always “fall of a cliff” after lunch? I was trying really hard to NOT be a fat bastard. You can imagine, I do physical activity, nutrition, and obesity research.  You lose street cred when you are fat.

My Solution:  Take up marathon running and starve myself.  This method got the weight off. It also made me sick and injured.  I was especially prone to colds and flu with several every year. I hate flu.

I finally got consistently injured enough to flag the running and take up age group triathlon again. Same results:  weight creeping, always creeping.  When it crept past an acceptable point, I’d starve myself and exercise like crazy.  I’d get sick.

Surely there has to be a better way? Enter, LCHF.

Now: I’m down to my lightest weight since mid-high school.  79 kg, lean, full of energy, and all the  injury and illness has gone.  I’m eating until full, as much as I like.  It’s Awesome.  I wouldn’t have believed this was possible.  But it is.

I started reading all the literature and science in nutrition, which has been part of my broader field for a while.  I have read enough now and experienced enough case work to change my starting hypothesis.

That’s partly why this blog is here.  That’s why I have changed my research and practice direction in physical activity, nutrition and obesity, as well as the broader area of well being. I am now up with the science and we need to do it better.

So what do I eat?

I don’t always eat three meals a day now. I often try intermittent fasting which usually isn’t planned but happens naturally* according to hunger, food availability, work pressures and convenience. For this to be possible is a revelation to me.  I have spent almost all of my life being pretty much hungry the whole time.  If I didn’t eat every few hours I would fall off a glucose cliff and basically become 50% functional.  This is hardly convenient and hardly optimal for a high performance life.  My new way of eating also allows me to easily create calorie deficits to manage my weight if I feel I need to.

*The fact that I can quite often end up fasting accidentally for relatively long periods, while staying mentally sharp and full of physical energy, is an amazement to me.  I’ve spent my whole life doing exactly the opposite.  It’s sort of like the “user manual” for being me has been found.  I am fat adapted and can oxidize fat as a primary fuel source. I can use ketones as a fuel for my brain.  I don’t fall off the glucose “cliff” every few hours.  This is a great place to be in.  It also means you lose the cravings for the sweet food, especially sugar. This is the main benefit most people I know who have moved into this style of eating report. The constant energy and loss of ridiculous hunger every few hours.

I also have the occasional off day or meal when I just do whatever I feel like.  We are all human after all.  I used to plan these for a while and really looked forward to them.  Frankly, now, I can do this if I want but I feel so crappy after eating simple carbs, especially wheat products, that I just don’t bother much.  Again, this is a revelation as my self control in the face of high sugar high carb foods in the past has been completely non-existent!

Here are some typical meals for me:


  • Scrambled eggs with whipping cream and streaky farm bacon from the butcher fried in coconut oil
  • Smoothie made with coconut cream or milk, whipping cream, coco powder and or fresh berries
  • Salmon, avocado and tomato
  • Omelette with cheese and veggies (meat added when I feel like it).


  • Massive salad with lettuce, tomato, capsicum, cucumber, cheese, meat of some sort – fish, chicken, bacon whatever is around, avocado, almonds.  Mix up and add copious amounts of dressing which is home made olive oil and vinegar or mayo.  The dressings have to be made by you, because almost all commercial dressings use hydrogenated vegetable fats – yuck – and are often high in sugar
  •  That’s my “go-to” lunch above.  I lack imagination for lunch according to my family, but that’s the way it goes!  I do have eggs and smoothies for lunch sometimes or something from the dinner/lunch list below.


  • Some sort of meat or fish.  Heaps of veggies (green and red veggies as a rule, cauliflower is also good, avoid starchy ones). I like pork with crackling. This is the time to really appreciate the flavors of fat.
  • Wine, although I am trying an alcohol free month right now because it was getting out of hand!
  • Berries and cream for dessert
  • Low carb cheese cake is a favorite

Other tips and traps

  1. Don’t trim fat. Healthy fats are monounsaturated olive and other nut oils, Omega 3 fish oils, and healthy meat fats (unprocessed red and white meats including beef pork, fish and chicken), as well as dairy fats. Coconut oil is great.  Avoid hydrogenated and polyunsaturated fats, especially in cooking.
  2. Just to reiterate, you have to replace carb and protein calories with something.  The only macronutrient left is fat.  Our ancestors likely coveted fat.  Fat, at least as far as insulin and leptin goes, is metabolically benign.  Carbs are not, especially when they are rapidly absorbed.
  3. Coffee is OK, I use whipping cream not milk. I tend to avoid dairy except cheese of all sorts (yum!) and cream.  Milk can be high in lactose (a carbohydrate). Those who are more carbohydrate tolerant (have an ability to eat carbs without weight gain) can go for full fat milk and a fuller range of dairy. Most kids are in this  category.
  4. Alcohol is a tricky question.  Alcohol is certainly not metabolically benign.  I recommend abstinence during the adaptation period into LCHF. Have a look at this link to explore more about keto/low carb adaptation. Then what you want is a low carb drink if you enjoy alcohol.  I certainly don’t drink alcohol for physical health reasons but I do drink it for social and marital health reasons!  My wife Louise and I spend lots of time sitting on our deck drinking wine and talking.  Great fun!  The active alcohol is called ethanol and is processed in the liver without much effect on insulin, at least not directly. It in fact follows a similar and dangerous path to the liver and beyond.  It’s metabolically active in an inflammatory and insulin resistance-promoting kind of way.  However, that said, we all have our vices, the actual insulin raising carbs in a glass of wine are between 3 and 6 g, depending on the wine and the size of glass (we have big glasses in our house!) so a glass or two is fine. Beers have way more carbs (12-20 g) per bottle and contain wheat that may result in other metabolic effects for some people.  You can get low carb beers of course.  I don’t really care for spirits, as a result of bad youth experiences I think, but if you do use them then it’s crucial to leave out the sugar based mixers.

That’s my wrap.  I’m not perfect and as a normal human fall off the wagon too.  I’m on the 18/21 plan. If there are 21 meals in a week, try for at least 18 good ones, hopefully better.  Let me know your favorite meals and we can post them up.

Diet wars: Can you really eat fat and get lean?

Grant Schofield doing the weekly LCHF shopping sans vegetables

Grant Schofield doing the weekly LCHF shopping sans vegetables, still to be purchased

There’s a food fight cooking…

In the red corner, we have the national nutrition guidelines, with its support crew of dietitians and most of the conservative medical and scientific community. They are the reigning public health champions. They are undefeated, but then they haven’t been seriously challenged. Until now.  In the blue corner, we have a new challenger. He’s been around a while but till now he’s just been shadow boxing. For some reason he strikes fear in those around him. I present to you…..Fat.

We’ve been told for decades now that saturated fat is the major enemy in the battle against obesity and chronic disease. Reduce your fat intake and eat more carbs instead we’re told.  Carbs are essential for human health we’re told.  Eat less, move more we’re told and you’ll stay in shape.  Here are the National Nutrition guideline for New Zealand.:

  1. Maintain a healthy body weight by eating well and by daily physical activity.*
  2. Eat well by including a variety of nutritious foods from each of the four major food groups each day:
  • Eat plenty of vegetables and fruits.
  • Eat plenty of breads and cereals, preferably wholegrain.
  • Have milk and milk products in your diet, preferably reduced or low-fat options.
  • Include lean meat, poultry, seafood, eggs or alternatives.
  1. Prepare foods or choose pre-prepared foods, drinks and snacks:
  • with minimal added fat, especially saturated fat
  • that are low in salt; if using salt, choose iodised salt
  • with little added sugar; limit your intake of high-sugar foods.

As well:

  1. Drink plenty of liquids each day, especially water.
  2. If choosing to drink alcohol, limit your intake.
  3. Purchase, prepare, cook and store food to ensure food safety.

* At least 30 minutes of moderate intensity physical activity on most if not all days of the week and if possible add some vigorous exercise for extra health and fitness.

Yep, that’s the advice and what I have been preaching publicly for the last 15 years, and practicing privately for my whole adult life.

So what’s the problem? The guidelines seem sensible right?  They’re evidence based, and the evidence is extensive right? Yes, sort of, and no.

Let’s deal with the Yes’s first:

Yes, there is extensive and compelling evidence that the type of diet described above is better for you than the Standard American Diet, henceforth known as the SAD :(.  This evidence is from randomized controlled trials, detailed longitudinal studies, and correlational studies.  There are plausible and known mechanisms for some of it, especially whole foods and meats. The important and convincing data around exercise and health is reflected in the guidelines too.

But that’s compared to the SAD.  It’s like saying that because studies show that smoking filtered, low tar cigarettes results in better health, less lung cancer, stroke, and heart disease than smoking roll your own cigarettes, that we should all smoke low-tar cigarettes. Bogus logic. 

The Sort Of’s

  • Sort Of: The part about maintaining a healthy body weight is true – that is good for you. And eating healthily certainly is the way to do this. A low fat diet could make this possible but in the 18 randomized controlled trials to date, where low fat diets have been pitted against low carb high fat (LCHF) diets, there is no instance where the low fat diet has outperformed the LCHF diet. Weight loss and risk profiles, including lipids, are all better with the LCHF. It’s been a knockout in every fight so far.
  • Sort Of: Salt raises blood pressure simply by increasing blood volume.  Equally, low salt is a risk for insulin resistance. Anyone who has ever completed a well formulated LCHF diet is aware of the importance of salt supplementation to prevent low blood pressure and cramps. The same is true for indigenous cultures who eat LCHF diets; they all add about 1.5-2.0 g salt a day.

The No’s

  • No: Where is the convincing evidence to say that saturated fat on its own is a health risk?  Here’s a recent meta-analysis of the longitudinal studies in the American Journal of Clinical Nutrition. There is no evidence of an association between saturated fat intake and cardiovascular outcomes in a combined cohort of more than 347,000 adults followed up for between 5 and 25 years.
  • No: Eat plenty of breads and cereals, preferably wholegrain, and limit your intake of high-sugar foods. Really? How about going with the more plausible mechanism for how we store fat in fat cells via raised insulin.  Insulin, you recall, is raised by carbs, even the so called healthy whole grains.  Sugar is an extra baddie – we all agree on that.  But the language is so lame, it almost condones anything other than high sugar.  Sugar and other insulin raising carbs promote hyperinsulemia, inflammation, glycation, oxidative stress, and fat storage. Because the inevitable outcome of a low fat diet is either starving yourself and keeping insulin under control that way, or a high carbohydrate diet. Either way, this regime is neither sustainable nor healthy in the long run. A low fat diet with sufficient calories for normal living is going to have to also be a high carb diet. Even if you eat lots of extra protein to avoid the extra starchy carbs, you end up with glucose anyway because excess protein will be converted, albeit inefficiently, into glucose in the liver via gluconeogenesis. 
  • No: A calorie is not a calorie.  Calories from different sources have profoundly different metabolic and hormonal effects in the body. Starchy and easily digested carbs raise insulin and insulin chronically blocks leptin. Protein raises insulin but the effect is short lasting and therefore satiating.  Fat is metabolically benign in the absence of chronically elevated insulin. This is why an “eat as much as you feel like” LCHF diet out-performs a low fat high carb diet. The way you get weight homeostasis is by controlling insulin. Perversely, the healthy food guidelines most governments push are likely to negatively affect the people who are highest risk the most; i.e. those who are less carbohydrate tolerant and therefore predisposed to excessive weight gain and insulin resistance in the presence of high carb diets. 

In the end, it looks a bit like the story about the time I was in a long distance ocean swim. The support kayaker taps me on the shoulder and says “You are going to need a change of strategy”.  “Why, I’m swimming flat out already” I reply.  “Because you haven’t made forward progress in an hour, in fact I think you are going backwards….”.  “I see, let’s talk about our options” I say.

We have to accept that we are making no progress in reducing the epidemic of obesity and chronic disease and we need to consider why. We need a discussion about our strategy.  This is the start of that discussion. We all agree that our industrialized food supply is bad but we don’t agree on how to change it and what nutrients are causing the damage.  We all mostly agree that sugar is a bad guy, but we can’t all agree that it is the effect of sugar on insulin and insulin resistance that is the problem. Yes sugar has fructose as well which has problems through other pathways. But, whether it’s loads of insulin-raising simple or complex carbs, it doesn’t matter – both need to be given the boot from the healthy food guidelines. In fact, perversely in my view, we ignore the fact that obesity is a metabolic disorder caused by any type of carb.  Sure, trans fats and the like don’t help. But let’s name the real VILLAIN here and now. It’s not saturated fat….it’s high carbs.

So what’s the answer?

  1. Stop doing nutrition research which tests one thing – the low fat dogma against the SAD. This is fundamentally bogus.
  2. Start doing research which has a start point in biology and evolution by natural selection.  That means start with some sort of paleo/primal LCHF as the “probably healthiest option” hypothesis.  Humans are omnivores = we eat plants and meat.  In human evolution, insulin was hardly ever raised excessively, and if it was, it was probably near the end of summer when man needed to pack away fat to survive the winter.
  3. Stop pretending we know everything about nutrition.  We don’t and we shouldn’t trust anyone who says they do. It’s a science in its infancy with a good deal of poor research behind it and an industry which has infiltrated research and public policy for its own benefit and not ours.
  4. Start to consider that like many other instances in human history, almost the opposite of what we have preached might be true.  Think Galileo, Hormone Replacement Therapy, causes of stomach ulcers, and dozens of times when medicine had it completely wrong.  It’s obvious that at least a few of the assumptions behind current healthy eating guidelines are bogus.

If you end up eating too many carbs in the presence of fat, no matter how paleo plant and meat based the rest of your diet, then all bets are off, you will get fat.

I’m writing this expecting to draw the wrath of colleagues, academia, government and medical and research conservatism. Hopefully first though they carefully consider points 1-4 above. What we need to start with is good science. I could be wrong, but so could you.

So let the diet wars commence; we’re in the ring and we’re ready to fight. We’re starting with the hypothesis that carbs make you fat, and that fat keeps you lean.  Bring it!

Footnote: There are typically three types of diet commonly and currently discussed; the LCHF diet, a low fat high carb diet and a moderate fat moderate carb diet (SAD). I want to reiterate that the SAD is the deadliest. A well formulated LCHF diet is not high protein, it is only adequate protein.  Low carb has nothing to do with dietary percentages.  It’s a total carb intake of <100g/day, maybe even <50g/day, or up to 150g/day for athletes. The LCHF approach is often confused by researchers and clinicians because I often see this regime criticised as either high protien, high fat, or the maount of carbohydrate quoted being far too high. Total daily carbs are what are important.

Thanks again to Helen Kilding in writing this blog

How to become a fat burning machine, lessons from athletes

Grant Schofield

Why become a fat burner?

In a previous post, Why some people stay skinny and others get fat I talked about how high carb foods lead to high insulin levels which effectively turn down, or off, your ability to burn fat. There is a longer downward spiral from years of this. But that was that post.

In this post, I want to look at exactly what you can do to turn yourself into a fat burning machine. This is not only about turning the fat burning on and creating a situation where you can drive a homeostasis for a steady and healthy weight, but is also about well-being and energy. My experience, as well as the overwhelming blogashpere and research itself, shows that an important benefit of fat adaptation is a much more stable energy level and well-being/mood.

We’ll look specifically at endurance athletes first. They want the same things that those who have problems with metabolic dysfunction want. They want to burn fat, not carbs, because humans have such a limited supply of carbs but much much bigger supplies of fat to draw upon. When athletes going long distances run out of carbs they are said “to hit the wall” or “bonk” (French for the noise your head makes when it hits the road?) So we’ll look at some of our lab results with an athlete later.

It’s not about treating carbs as evil and trying to run your body without carbs. In some ways it’s the exact opposite – it’s about sparing the glucose you do have. It’s about getting your body to do what it is designed to do under usual evolutionary conditions – burn fat and have enough energy to move all day and/or make short intense bursts. Becoming an efficient fat burner allows you to do just this.

Carb burners v Fat burners

If your metabolism is set up to predominately burn carbs, then you’ll most likely have many more highs and lows throughout the day energy wise. I call the lows “falling off the glucose cliff”. That’s when your glucose dependent brain cries out for more fuel – in the form of simple carbs usually. The cycle continues. If that’s you, then this blog could change your life for the better!

There are many plausible or proven health benefits here to. There is the obvious one of easily being able to control your weight. But far beyond that is reducing the damage high sugar, and high insulin, and sugar burning (glycolysis) do in your body. All of these are inflammatory and cause oxidative stress. These are the causative mechanisms behind chronic disease development including heart disease and stroke, diabetes, cancer, and brain (dys)function.

Fat burning in endurance exercise

One lab-based method we use to measure fat burning vs carb burning is the respiratory exchange ration (RER), also known as the respiratory quotient. This is the ratio between the amount of carbon dioxide exhaled and oxygen inhaled, which provides an indication of which substrate (fat, carbohydrate or a mix) is being used for fuel. We do this using our breath by breath gas analysis system in our Metabolic and Exercise Science Clinic at the Human Potential Centre at AUT Millennium Campus.

The RER varies between 0.7 (100% fat burning) through to ≥1.0 (100% Carb burning). A ratio of 0.85 has been labelled the metabolic efficiency point, when the body burns half of each. We try to determine what exercise output can be maintained for half and half. Bear in mind that everyone will eventually burn 100% carbs if the exercise is intense enough, but the higher the intensity at which fat is still the predominant energy source the better. However, what we are most concerned with is the ability to burn fat at rest and at lower to moderate intensities of exercise. This is great for weight loss. It’s great for health. But it’s also great if you are an athlete trying to do longer distance events like the Ironman triathlon.

We recently had a high level triathlete in our lab. We measured his RER before and after a 10 week training block going into this year’s Ironman NZ. We also transferred him to a low carb high fat (LCHF) diet for the period of that training. He was training about 20 hours a week and came in to the 10 week block relatively fit, albeit slightly heavier than he wished.

Some stats:

  1. Start weight 86 kg, post weight 78 kg. Good weight loss while reporting eating until full. No deprivation of food or calories if needed. Reduced calorie consumption on long training sessions. Few if any gels or sports drinks.
  2. Pre RER @ 270 W bike = 0.93, post RER @300 W = 0.82. This translates to a change in fat utilization from 23% of fuel to 60% of fuel at the same power output, for a lighter overall weight (power per kilo was also increased).
  3. Metabolic efficiency point (50/50 fuel use) improved from 180 W to 300 W. This shows the massive increase in efficiency we saw with a switch to a LCHF diet.

If you know anything about endurance training and racing then you’ll know that these results are outstanding. To the point of being spectacular. The limiting factor in longer races is not maximal output, but how fast you can go while conserving muscle and liver glycogen (carbs). You need to maximize your fat burning and preserve your very limited supply of carbs as much as possible.

Most athletes try to get around this problem by eating extra carbs during training and racing. This can work to an extent, but perversely raises insulin and shuts down your body’s ability to burn fat. It’s almost impossible to eat and digest enough carbohydrate to actually race these events well. You need a good degree of fat burning.

Anyway, this illustrates what can be achieved with a LCHF diet; good, effortless weight loss and spectacular performance gains.

If you’re not an athlete, and I’m assuming most of you are not, then the same principles still apply. We can hook you up to the gas analysis system and determine your “metabolic efficiency” at rest. We can assess just how much of a carb burner you are and we can track your progress if you decide to become a fat burning machine through a LCHF diet.

Fat adaptation v ketosis

There’s a special type of low carbohydrate diet called a ketotic diet. I want to explore that in the next post. Stay tuned.

Thanks to Helen Kilding for her help with this blog

Why some people stay skinny and others get fat


What I want to put forward today is that there is evidence for two distinct modes of human metabolic state. One is being “fat adapted”. That is, a state where the hormone insulin is well controlled and the body is able to access its stores of fat as a primary source of fuel. This, I contend, is the normal human state. The complex interaction of cells, hormones, enzymes and much much more is in balance.  We homeostatically maintain a desirable body weight by self-regulating inputs and outputs. In this state, if we over-eat, we will compensate and burn it off.  And vice versa if we under-eat. The mechanisms are complex and not all are well understood.  It’s at least a great starting hypothesis.  Good science is  needed to nail down the whole mechanism but putting together animal and human evidence points to this.  This is fundamentally why the “calorie is a calorie” dogma that has plagued nutritional science for the past 40 years is wrong.

When you are “fat adapted” you can easily utilise fat, you have less craving for simple carbs and, most importantly, insulin is well controlled.

However, when you continually eat large amounts of carbohydrates, especially simple refined carbs, then the second mode of human metabolic state results and the body becomes what I have decided to term “metabolically dysregulated”. Others have used the term “metabolically deranged”, but I find that a little too emotional!  The mechanism is simplified as follows:

  1. The body has to continually deal with large loads of dietary carbs.
  2. It does this by producing insulin, a storage hormone which shuts off the ability to burn fat as a fuel source and get carbs into cells. Some will go into muscle cells (especially in an active individual); some goes into the liver; but if the muscle cells and liver are full, which they often are because they have a limited capacity and people often expend very little energy, then the carbs are stored in fat cells.  That’s the basic mechanism for the storing of fat.  Insulin also drives extra fat into fat cells too. That’s it. Simple.  Insulin makes fats cells get bigger. Without a rise in insulin, there is no easy mechanism for this process.
  3. Insulin also blocks an important hunger hormone called leptin. Leptin is secreted by fat cells and signals to the hypothalamus in the brain that the body is not starving. By blocking this hormone, insulin is effectively block the “off switch” for hunger so we over-eat.
  4. Insulin also down-regulates (the process by which a cell decreases the quantity of a cellular component) the pleasure hormone dopamine’s receptors in the brine. This is what gives simple carbs their addictive quality.
  5. Insulin also down-regulates sympathetic nervous system activity resulting in a reduced propensity to expend energy through both incidental and purposeful physical activity.
  6. It’s a downward spiral as you get fatter and less regulated and continue to bombard the body with large doses of dietary carbs. You become more and more insulin resistant, both at the muscle and liver cell level.  In other words, you need more and more insulin to get the carbs into the cells. Insulin is permanently high.  So your cells become more existent.  You are always storing fat, never burning it and a state of hyperinsulemia (high insulin) ensues, even when you are not eating. You become fatter, especially around your central area (visceral obesity), which drives more inflammation and increased insulin resistance.  Oh boy….!
  7. Eventually, the beta cells in the pancreas which produce insulin start to fail and you can’t manage your blood sugar levels at all. That’s Diabetes. Constantly high blood sugar is toxic to all parts of the body it touches, and it touches everything of course.

So that is what I call becoming metabolically dysregulated.  It is caused by lots of simple dietary carbs. It’s a pandemic.  It’s because we have a food supply choked full of processed carbs. And even worse, our medical advice is to go low fat. Low fat, by definition, will mean high carb for the body.  More on why in later blogs.

So that’s the dietary choice you have in my view. Eat whole unprocessed foods; low carb, leafy vegetables, moderate protein, high fat and you will avoid the insulin peaks and eventual dysregulation described above.  Eat the carbs, send insulin way up and suffer the consequences of metabolic dysregulation. Fat burning shuts down,energy out shuts down.  Fat storage goes up.  Because energy out is synonymous with quality of life, you feel crap. Being the best you can be has a central requirement of being metabolically well regulated.  That’s why I am so interested in nutrition.

Thanks to Helen Kilding for her help with this blog

Fat airfares – what’s fair?


OK here it is for real at last. We’ve been talking about it for a long time long. The whole airline business comes down to dollars and sense. It’s competitive, and every extra kilo costs extra fuel and aircraft wear and maintenance. Business is business, someone has to pay, and it really comes down to the customer in the end. If you are fat, you should pay more. You’ve eaten too much and moved too little. You gluttonous sloth, you should have tried harder.

Samoa Air now charges by the kilo. You’re an undernourished kid, cool – its very cheap. You’re an obese adult with a bit of luggage. Get you credit card ready. Hopefully it won’t be declined. Hopefully you haven’t put on any weight when they check/weigh you in.

On first pass, as a lean member of society, I agree with Samoa Air. I want to pay less because I weigh less. Why should I subsidise some 200 kg super beast?

And, Samoan Air isn’t really the first to do this. The reality for many morbidly obese people is that there is no way they can travel on a conventional commercial aircraft in a single seat. They end up having to pay double to fit themselves in. It’s simple physics right? No way to fit an incompressible mass into the volume of that seat.

OK, so what this really comes down to is what I want to spend the next few blogs and more on. What is obesity? Why does it happen? Why has it spiraled out of control everywhere? Who should be responsible for fixing this problem? How do we fix it? Is it even possible to fix it?

Back to Samoa Air. Their CEO describes it as a positive health promotion strategy. “This is the fairest way of travelling,” he told ABC Radio. “There are no extra fees in terms of excess baggage or anything – it is just a kilo is a kilo.

“When you get into the Pacific standard weight is substantially higher [than in south-east Asia] but it can be quite diverse. People generally are becoming much more weight conscious. That’s a health issue in some areas. It has raised the awareness of weight.”

Really? A health promotion strategy? Seriously? If only they knew that weight was an issue then they’d be thinner? I doubt there is anyone who wakes up and wants to remain obese. Has anyone seriously ever woken up and said to themselves “today is another day to get fat, bring it on!”

The debate centers on whether people are fat because they eat too much and move to little. This is conventional obesity wisdom, that a calorie is a calorie, and the only way to become obese is to eat too much. By definition, you cannot defeat the laws of thermodynamics. Therefore obesity is caused by gluttony and sloth. The cure therefore is obvious, raise awareness, tell people to get off their arse (move more) and eat less. Problem solved.

This is what drives most of public health effort around obesity, as well as the commercial and ethical response.

Except, we’ve already thought of that in public health, and it doesn’t work.

It doesn’t work, because it’s wrong. Straight wrong. The real problem is more complex and deserves your attention. It deserves your attention because no matter how lean you are, you too will at some point in your life have trouble controlling your weight. You will almost certainly have your life affected because others close to you struggle with their weight and the chronic disease being obese brings with it.

Let’s put out the alternative hypothesis. Obesity is a disease of excess fat accumulation. It’s a metabolic disorder, or at least metabolic dysfunction. Sure, gluttony and sloth are there. But they are symptoms, not causes. This metabolic dysfunction is caused by hormones. Those hormones are complex, but primarily relate to insulin and leptin.

Put simply, when insulin is raised by excessive loads of simple, refined carbohydrates you turn off fat burning and promote fat storage. Insulin blocks leptin – the off switch in the brain. Insulin down-regulates dopamine, the pleasure neurotransmitter in another part of the brain. You think you are starving, you crave more, and you move less. Gluttony and sloth symptoms, not causes. All extra energy is stored as fat. You can’t burn fat. You feel lethargic and tired. Your body goes into storage mode. It’s a great mode if you are harvesting late summer and have a winter or famine to survive.

We are coming back to this mechanism in way more detail in later blogs, don’t fret!

So here’s my bottom line. Obesity isn’t the fault of the individual. It’s the fault of the food supply. It’s the fault of bogus dietary guidelines that promote low fat, high carb diets. It’s the fault of society as a whole and we need to deal with it with science that hits the mark.

Science to date in nutrition hasn’t hit the mark. More to come on that too.

So that’s the debate. How do we deal with obesity? Samoa, one of the fattest countries in the world has started by putting some of the burden on the victims, not the perpetrators.

Am I right? What do others think? Here’s a reaction from a good friend of mine today. He’s very well educated and a great thinker.

MCI am not so sure there is anything weird in this. Now days, user pays underlies almost every aspect of our lives – and certainly every aspect of discretionary private spending (with limited exceptions such as where it is economically rational for a company to charge customers on the basis of a cross-subsidisation methodology). With any air transport, weight is everything – the more something weighs, the more fuel gets burnt, the more it costs. We accept that in the context of cargo. Why not people? Because it is “unfair”? Really? Airlines work out fares based on average weight. Any given passenger is either above the line or below it. If you are below it, you are subsidising those who are above it; if above it, you are being subsidised. It makes no sense to say that big people are being punished or treated unfairly if they are charged a fare that reflects the greater cost to the airline to transport them. What is unfair is that those passengers who are below the line have to pay more to travel than they otherwise would have to because there are fat people who also want to travel.”

From the NZ Herald

Absolutely, but as long as you get the equivalent seating space to go with the cost. You pay more, you get more.”


“Being attacked by an obesity expert and community leaders as insensitive and lame……

if people want to use those word’s ‘insensitive and lame’ they are just enabling obese people to think that being overweight is ok, and it’s not, it’s unhealthy… it’s nothing else but just plain unhealthy.

You go Samoa airlines you rock. It is a good thing to pay by weight….. you have to if you are posting a parcel don’t you? BTW I am a few kilos overweight.”

I had trouble finding anyone except the “lame obesity experts” sticking up for the fatties. Look, obesity is a massive issue (pun intended). It’s something we haven’t been able to sort. The science is becoming increasingly obvious, but the practice of helping people isn’t doing the business. It’s time for a new approach. Let’s see what actually works.

Stay with the blog and we’ll find some solutions that help us be the best we can be.

The structure of great communication

This is a great TED talk by presentation guru Nancy Duarte. Her ideas about speaking are what you get given when you are invited to do a TED talk. It’s a really powerful and simple analysis of great speeches in history including Martin Luther King’s I have a dream speech and Steve Job’s IPhone launch speech in 2007.

Great communication is of course essential to changing the world. It is essential to any good idea. Without great communication, great ideas are lost. Mediocre ideas can flourish because of great communication. That’s such a shame on both counts. The good news is that this is totally learnable. I did it myself in my TED talk which I’m pretty proud of.

The basic idea is that great speeches all have the same structure – a shape which describes how the world is, and then switches back to how it could be. It always ends with the “new bliss”. It pulls the audience between what is and what could  be  –  the powerful idea you have of “the new bliss”.

Enjoy the video.

Be the best you can be


(pic: the entrance to AUT Millenium where I work)

I’ve wanted to start a blog for quite some time now. The trick is to get the technical skills together well enough to actually know how to run one and do it regularly. Well, I’m just about there.

What will I blog about?

I am really interested in the science of how we can be the best we can be. This crosses disciplines such as biology, medicine, pubic health, and productivity management. The cornerstones are nutrition, exercise, sleep, neuroscience, psychology and well-being. I’ll be covering these topics under the broad heading of the Science of Human Potential (the name of this blog).

I’ve been interested in human health and performance for my whole career. I started in psychology then into sport and exercise psychology, then into public health especially physical activity then obesity.

There have been some twists and turns along the way which might help to give a view of why I do what I do and where it can go.

About me

Sport and exercise has always been a massive part of my life. From an early age I played rugby union, learned to sail and race, and eventually ended up in the high school rowing squad. Rowing at my high school had no room for anything but high performance. So I was introduced to this at age 13. From there we won national championships most years. The combination of the sheer physicality of the sport and the team work and individual excellence required both mentally and physically really defined my teenage years and who I could become as an adult.

Being fit and involved in some sort of high performance activity has been part of my life since then.

I finished bachelors, Honors, and doctoral degrees in psychology at the University of Auckland by 1994. At the same time I had got into triathlon as a sport. I ended up racing semi-professionally. That’s code for “was never quite fast enough to earn a decent living, so had to supplement prize money income by working“. In the end I raced professionally in several world championships in long course triathlon, ironman and duathlon. That was great fun, and the skills and work ethic I have learned from triathlon are important to me.

The extra benefits from the high performance sport world, especially triathlo,n include:

  • I met my wife Louise because of triathlon. She ended up also as a professional triathlete, a better athlete than me. We’ve been married since 1995 and have three boys – Sam, Jackson and Daniel. Louise also started Vitality Works, a workplace health company acquired by Sanitarium in 2012. Vitality Works has allowed both of us to benefit from a huge amount of professional and personal development in health and well-being.
  • I figured out early that a high performance life is just as much work as a low performance life, so you may as well take the high performance life. It just requires a bit more work up front, but frankly you avoid work later and you get more choices.
  • I have the skills to stay fit and enjoy maximizing my biology for my own personal peak performance.
  • I still get to compete at a reasonable level in triathlon and running. This is cool because the age group triathlon and running groups are really fun, and you get to hang out with people of a similar performance, health, and happiness mindset.

My academic career began with part-time teaching in the Psychology Department at The University of Auckland during my PhD tenure. I moved to Australia (Central Queensland University in Rockhampton) and worked in the School of Psychology there for nearly 10 years. Most of our spare time then was dedicated to triathlon training and racing with Louise. I wasn’t going fast or far in the academic world at that point. Enter Kerry Mummery.

Kerry Mummery is now the Dean of Physical Education at the University of Alberta. He really mentored and started me on the journey to becoming a decent academic. We worked on several physical activity and health projects together. The most notable was 10,000 Steps. This started as a whole community project and morphed into a nationwide program which is still running successfully today.

This was the entrance into public health proper for me. I started at AUT in 2003 after the birth of Jackson our second son. Back in Auckland and into a new country with plenty to do. That’s when things really took off. I had the good fortune to have several great staff members and PhD students under my guidance. Almost all of these are still with me.

The highlights in the last decade are:

  • Working with dozens of talented doctoral and masters thesis students
  • Being highly successful in obtaining research grants and funding. This is the life of an academic and you live and die by this success. We are up over $20 million in funding.
  • A solid and respectable publication record. Ditto above. Important for gauging success. But by itself is unlikely to put much of a dent in the universe.
  • Being involved in Vitality Works. This has put a dent in the universe and allowed me to develop more formally into peak performance, well being and neuroscience.
  • Being the youngest full professor around for a while. That wore off as I aged!
  • Moving our work beyond physical activity into obesity, well-being, productivity, and nutrition/weight loss. Most recently the work we are starting in metabolic efficiency and weight is likely to put the biggest dent in the world.
  • Starting the Centre for Physical Activity and Nutrition and eventually morphing that into the Human Potential Centre at the new Millennium Campus.

So that’s where I’m at. Where I want to go now, and with this blog, is to explore the science behind what helps us “be the best we can be.” It’s an emerging and multidisciplinary science. Let’s go!