A short post on how fermentation of resistant starches in the gut into short chain fatty acids (SCFA) works and the role it plays in human and other animals’ diets.
I direct you all to a really nice review paper in the journal “Physiology Reviews” for way more expert and in-depth analysis than I can do. You better have some good biochemistry if you want to understand that paper though. Frankly, I was struggling by the end.
I am writing this because I have had a problem reconciling why mammals can have such varied diets yet end up running pretty similar organs and homeostatic biological systems. Even within humans, at least in the non-industrial food environment, we can flourish on such a wide range of macronutrients.
At one end of the animal kingdom we have herbivores, such as cows and gorillas, eating plant only diets. At the other end we have carnivorous cats of various sorts, like tigers and lions, eating meat. One end appears to be a low fat, high carb, moderate protein diet. The other is a high fat, high protein diet.
Humans are the same. We have Inuits at one end on a high fat, virtually no carb, moderate to high protein diet. At the other end we have the Kitavans in Papua New Guinea who eat high carbohydrate diets (have a look at Dr Staffan Lindberg’s site on this – it’s quite interesting). Yet both groups and all of the ones in between in their natural food environment are metabolically healthy and free of chronic disease. The same is true for the animals as well. All have no trouble maintaining a healthy weight even in the presence of plentiful food.
So what goes? And why do I talk about a low carbohydrate diet in the midst of all this evidence?
My short answer is that a whole food diet is fine in any macro-nutrient composition as long as you are metabolically healthy. But as soon as you become dysregulated (aka insulin resistant) – probably because of sugar and other lifestyle factors, like excess stress – then carbohydrate restriction is the way back out of this. This is probably half the western population, maybe more.
Why? Well the longer answer is that there is something else to consider in the animal and human digestive systems which further helps us (or me at least, and hopefully you too) reconcile the variation in carbs/fat/protein across animals and humans.
The emerging evidence it seems is that plant fiber is fermented in the gut of herbivores and omnivores, including humans. This provides energy in the form of short chain fatty acids, especially butyrate.
This is really cool because it means that the range of macro-nutrients which makes it through the gut into the actual bloodstream of all these very different, but similar, animals is similar. It’s much higher in fat than we previously thought. For example, studies with Western lowland gorillas shows that the majority of their energy (57%) comes from the SCFA fermented in the gut from vegetable fiber (SCFA are saturated fats!). Most of the animals we are considering, including humans, are on high fat, moderate protein, lower carb diets – give or take – once we take into account fiber fermentation in the (healthy) gut.
“The macronutrient profile of this diet would be as follows: 2.5% energy as fat, 24.3% protein, 15.8% available carbohydrate, with potentially 57.3% of metabolizable energy from short-chain fatty acids (SCFA) derived from colonic fermentation of fiber. Gorillas would therefore obtain considerable energy through fiber fermentation.”
Where things go astray is when any of these animals, including humans, eats processed carbohydrates. These aren’t high in fiber of course and go straight into the bloodstream. Insulin is constantly high in an attempt to move the carbs and it’s downhill from there.
Other researchers might have known about this for a long time, but I was sticking to the old “roughage hypothesis” of fiber digestion. That is, the idea that the fibre wasn’t digestible and helps clean out and stimulate the colon.
So what of humans then? I think we can take a few things away:
- Fermentation of fibre, like in herbivores, occurs in the human colon
- Much of this turns into usable SCFAs. Some feeds the actual bacteria, some the gut wall and some goes into the bloodstream and is processed from there.
- The calorie count on products which contain fiber is flawed, and another reason why a calorie is not a calorie. Celery is a good example of this; people claim celery contains less energy than it takes to digest – true enough, immediately available carbs are low, but the fiber fermented into fat contains significant amounts of calories in SCFAs.
- High carb diets which are high in fiber can turn into higher fat diets, and that is likely what has been the case historically for humans.
- Microbiome health is likely to depend on establishing quantities of bacteria which can digest fiber. This will depend on the history of feeding that sort of food. Processed carbs probably undermine the development of the gut bacteria needed to digest fiber.
- And processed carbs bypass the entire mechanism and dump insulin raising carbs into the system further upstream from the stomach and small intestine.
Here’s a nice report back from a (kiwi) triathlete living in the Middle East who has become fat adapted and losing some weight in anticipation of the world champs in a couple of months. I think I talked her into a “trial” period of the LCHF, whole foods approach. This is her report after a few weeks.
Things are going well –we are well into week 3 .. or maybe it’s week 4…and don’t really see the need to “come off” adaptation phase… although close to giving into my on-going craving for whole grain buttered toast with manuka honey!
GS: JUst eat the damn bread and honey and you will probably feel a little bloated and decide that the thought was better than the actual real thing! Also carbs aren’t that dangerous….you did need to seriously restrict them to adapt though.
I’m enjoying the benefits of no slump in the afternoons.
I’ve become sick of eggs and have moved to a smoothie for breakfast and lunch –
Am really starting to cram everything possible into them! Loving it. Complete meal in a glass – yum – see pic of regular ingredients.
We are going through peanut butter like nothing else! So I have started making our own – success!! Who’d have known!? So easy!!! Tip salted or dry roasted nuts in a blitzer and 3 minutes later…. Delicious sugar-free and palm oil-free peanut butter 🙂
I am quite happy to continue – we have pretty much removed all sugar…. In-fact I had a fruit salad the other night and felt both very naughty and high from the sugar! In addition to my craving for toast with honey (… seems like a cardinal sin) I’m tempted by a few dates or prunes that are hidden in the naughty cupboard…… But I figure if these are my only “slips” I’m not doing too bad.
I’m consistently under 60-61kg now and nudging <60kg . Almost goal race weight.
One thing I found interesting over the weekend’s more testing session – the chomps that I was having about 50 mins and 1hour 30 mins into the session were really noticeable. I really felt the boost and as a result think I had a better training. Basically it was 90 mins of max accelerations (3 x pyramid from 10 sec to 60 sec) on the turbo and then 40 mins run off the bike including 15 x 30sec on-off efforts. Last weekend on the bike I really struggled and found it soul destroying trying to accelerate / hold max speed for 60secs and unable to hold max speed for long. This weekend I did much better and only towards the last 5-10 seconds did I loose power and the speed started to drop. I really think the new diet helped with endurance and enabled the carbs /fuel to really do their job 🙂
So things are going well and over-all Tim and I are noticing that we are eating a lot healthier and a lot less in each meal – get full earlier. I’m on the hunt for new recipes –bored of eggs ! and want to mix up dinners a bit. I think we run the risk of becoming smoothie junkies! They are so easy and satisfying! Will try lettuce leaf tacos this week and some sort of quiche or egg tart / pie…..
Anyways –feeling good and happy about the diet! Really glad we made the switch.
I think she’s doing pretty well. My advice is really around using carbs in training when the demands of her training session warrant it. I’d still prefer the majority of training wasn’t in the mid-chronic cardio zone. But if she is going there, then take the carbs you will need them.
Otherwise, mission accomplished so far, which was learning about how to be come fat adapted, eating whole foods, making a race weight and maintaining even energy.
My dog eats pretty much anything, except three things which he doesn’t regard as food. These are – Big Macs, his own crap, and some commercial dog foods. Other than that he’s good to go.
But what should dogs eat if you are trying to apply a paleo/primal philosophy to your whole family, including the dog?
I’m onto my third border collie, Bluey. I love running and playing and generally having him as part of the family. Our family eats whole food with a paleo philosophy where possible. That considered, what should Bluey eat? He’s a dog, not a human, and humans and dogs (probably they were actually wolves then) came together around the time of the agricultural (see a study on this) revolution. There have been many more generations of dogs than humans over that time. They have had to change with us alongside us selectively breeding the ones we wanted.
There is evidence that they are adapted to digest starches better than their wolf cousins (see study In Nature). In fact, there is no such thing as a “paleo” perspective for a dog because they weren’t around in their current form. My take is that modern dogs are in human symbiosis.
So I’ve been thinking a lot about what would be a healthy diet for Bluey.
Here’s what I have come up with – along with some principles.
Commercial pet food?
I am assuming that because there is no law in most countries (including NZ) that requires manufactures of pet food to have actual nutritional composition on their food, that this means that the food is probably relatively low quality. Nutrient density is likely to be poor, and how animals do on these sorts of foods is unlikely to be explored.
My bottom line assumption is that there is no sensible business reason for pet food manufacturers to make high quality food. Even the premium brands; we have no way of knowing what is actually in them and if animals do well on them.
Should we ask veterinarians what they think on the issue? Probably not…they have a serious conflict of interest. It’s such a hard business to make money as a vet. No government subsidies. Pet food is a big earner and they survive by selling you this stuff. I’m assuming most vets do actually like animals and want to see them do well, but they really have no training in the science of nutrition (although to be fair that training in human nutrition appears to have been a disadvantage in modern medicine).
Bottom line: Modern commercial pet food is almost certainly poor quality and scarce of nutrients. There is no sensible commercial reason to make it high quality. Avoid it.
ps, if someone can show me some “nutrient dense” commercial food then cool.
Are dogs carnivores?
Nope, they can eat starches and other veges. They can eat raw meats and be quite happy. The have a mouth structure which is full of canines, some molars (I can feel a couple at the very back of Bluey’s mouth) and some small incisors at the front. I am assuming that are evolved to chomp up things tother than meat and bones.
So what is Bluey eating?
- Whole rabbit – shot on Great Barrier Island and bought from Canivoro in Akotaganga Drive, Northcote (who I don’t get free stuff from and have no financial interest in). I’m assuming that a whole wild animal eaten raw with bones and organs has some decent nutritional value for a dog.
- Some dried food – we are using the last of it. I agree its crap but I’m too tight to throw it out!
- Goat, beef, horse – again from Carnivoro – same as above; at least likely to have some nutritional density.
- Bones – lamb shanks, pork ribs, chicken carcasses etc – Our family eats all these meats and what we don’t eat we give to Bluey. I am assuming that scavenging off humans for bones is likely to be a “evolutionary heritage” for modern dog?
- Left overs – bacon, eggs and other scraps the kids throw to him and various left overs on bowls that he displays some interest in. Frankly, this is simply laziness as it helps us do the dishes (the first stage of it anyway) and produces less waste. We do wash the plates properly after Bluey’s done his bit I promise!
- Crap – from any other animal including humans (some claim this is the reason they became endeared to humans in the first place!). I don’t willingly feed this to him as it grosses me out, especially when he later licks me….but he finds shit around the place from time to time.
What he doesn’t eat
The only things he has sniffed and walked away from are:
- a Big Mac
- Several varieties of commercial dog food. I guess he didn’t regard that as food!
- His own crap
Can you have a vegan dog?
Apparently there are such animals living quite well and actually having quite long lives. Who knows how or why? Perhaps they do have such metabolic efficiency. Perhaps they are essentially on severe caloric restriction and therefore live longer like other calorie restricted animals do. Who knows?
I doubt any dog willingly chooses not to eat raw meat though!
I’ve had three family dogs – all border collies. The one in the picture is Bluey, a 15 month old red/white border collie. He’s a friendly and active fellow, on a whole food meat and other stuff based diet.
I wanted the smartest, most active dog because my view was that they would need exercise and that would force me and the family to do more exercise. So is that likely to work, or is the dog more trouble than he’s worth and you just spend more money and can’t holiday when and where you like?
Well the original big dog in the research into dogs and physical activity was Prof Adrian Bauman and his dog Schroeder (a Jack Russell). Schroeder is the first dog I know to be a published author on a research paper.
Anyway, Adrian is back with a team reviewing the benefits of dog ownership on physical activity in the latest issue of the Journal of Physical Activity and Health.
There are now 29 studies looking at this, including one by me almost 10 years ago. I showed that dog ownership wasn’t enough; you needed to have at least a middle to big sized dog!
So what has the latest review shown? “Approximately 60% of dog owners walked their dog, with a median duration and frequency of 160 minutes/week and 4 walks/week.” Dog owners on average are slightly more active than non-dog owners, but the effects are small. We don’t know if giving someone a dog helps them be more active. In other words, we need dog intervention research!
So is it worth having a dog? Probably. There are numerous benefits, including some extra activity. Are there hassles? Damn straight there are. Mine crapped in the kitchen overnight and I was the one who got in trouble for it, and I even cleaned it up!
There’s something else about being out with a dog too. The sheer primal nature of it, the ability of the dog to draw you into the moment of being alive. Running on an empty beach. Chasing seagulls. It’s great fun.
How happy are you? How well are you doing in your life? How happy are New Zealanders, and how do they compare with other countries?
All big questions. You can find out how you compare with the average New Zealander of your age and sex here. You can access the Sovereign New Zealand Wellbeing Index here. You can view TVNZ’s Sunday episode aired on the topic here.
I am very proud to announce the public release of this Sovereign New Zealand Wellbeing Index. It’s the first survey point in a six-year research partnership with Sovereign . It’s also the first time anyone has tried to understand the epidemiology of wellbeing in a large (n=10,000) population representative sample in NZ. We will follow some of the same cohort across the six years. The basic logic is that if you want to improve the wellbeing of the population, then first you had better measure it, and generate some hypothesis forming associations.
We also used the same measures as used in the European Social Survey wellbeing module.
So this has been several months’ work for me, and even more work for my dedicated research team, as well as a team at Sovereign working on the comms side. Thanks everyone for the enormous amount of work.
Actually, that’s been the coolest thing about this project. The well developed comms and advocacy angle that Sovereign has been able to bring to the partnership. They’ve got an interest in reducing stress and increasing wellbeing straight out form a claims perspective as well as the corporate social responsibility angle
Frankly, we are very used to doing high quality research which mostly gets published in journals a few people read, and a few masters and PhD theses which even fewer (maybe even only a few!) people read.
So now, we have had a great link into releasing the report, advocating government and policy makers, getting TV and media coverage of the results and so forth.
Mostly, I’ve been blogging about nutrition, exercise, weight loss and chronic disease prevention and treatment research at the Human Potential Centre at AUT University. That’s where I am a Professor (Public Health) and the Director of this research centre. I will do a few more blogs in the wellbeing space to augment this report release.
Wellbeing is an area we are really getting into. We are trying to bring many of the principles of positive psychology into health. We also want to bring some of the principles of health, especially nutrition and exercise into positive psychology. Each discipline has lots to offer, but combined even more so.
These sorts of national accounts or indices of wellbeing have become popular in Europe recently and other less robust world-wide measures like the Happy Planet Index. To our knowledge, we are the first to do both mainstream health measures and wellbeing measures.
Sunday on TVNZ did a great job of presenting some of the results. Thanks TVNZ. See here.
You can go online and either take the entire survey and see what we measured, or just the “7-item flourishing scale” Goto www.mywellbeing.co.nz. We have the norms for your age and sex, so you can compare you results with those overall and of similar kiwis in the survey. Have a go its fun. Take the quiz.
Results for the Sovereign Wellbeing Index (This is the exec summary – get the full report here)
This report presents key findings from the Sovereign Wellbeing Index about the wellbeing of New Zealand adults in late 2012. The survey is the first national representation of how New Zealanders are faring on a personal and social level. The Sovereign Wellbeing Index provides a much needed look into how New Zealanders are coping within the economic conditions.
Wellbeing around New Zealand
Using flourishing as a measure of wellbeing there were small but consistent effects of gender, age and income. Older, female and wealthier New Zealanders on average showed higher flourishing scores. Similar findings were found across all other measures of wellbeing giving some confidence in the convergence of measures.
- There were only small differences in average flourishing scores between ethnic groups (NZ European slightly higher than Asian) and regions across New Zealand.
- Social position was a powerful indicator of wellbeing. Those higher on the social ladder reported much higher wellbeing.
- The five Winning Ways to Wellbeing were all strongly associated with higher wellbeing. People who socially connected with others (Connect), gave time and resources to others (Give), were able to appreciate and take notice of things around them (Take notice), were learning new things in their life (Keep learning), and were physically active (Be Active) experienced higher levels of wellbeing.
We looked at the 25% of the population with the highest wellbeing scores and examined what factors defined this group from the rest of the population. This underpins the idea that psychological wealth and resources can be identified and public policy and action, and personal resources utilised to improve these determinants.
- Similar findings to wellbeing in general were identified. Females were 1.4 times more likely to be in the super wellbeing group than males. More older, higher income, and higher social position New Zealanders were in the super wellbeing group.
- Connecting, Giving, Taking notice, Keeping learning, and Being active were all strongly associated with super wellbeing.
- Other health measures were also strongly associated with super wellbeing. These included better overall general health, non-smokers, exercisers and those with healthier diets and weights were all more likely to experience super wellbeing.
When compared with 22 European countries using the same population measures, New Zealand consistently ranks near the bottom of the ranking in both Personal and Social Wellbeing. New Zealand is well behind the Scandinavian countries that lead these measures.
New Zealand ranks 17th in Personal Wellbeing. Personal Wellbeing is made up of the measures of Emotional Wellbeing (rank 16th), Satisfying Life (rank 16th), Vitality (rank 16th), Resilience and Self- esteem (rank 19th), and Positive Functioning (rank 23rd).
New Zealanders did however rank above the mean for happiness, absence of negative feelings and enjoyment of life. However, we were still well below the top ranked countries.
New Zealand ranks 22nd in Social Wellbeing. Social Wellbeing is made up of the dimensions of Supportive Relations (rank 21st), Felt lonely (rank 20th), Meet socially (rank 21st), Trust and Belonging (rank 23rd), People in local area help one another (rank 21st), Treated with respect (rank 22nd), Feel close to people in local area (rank 23rd), and most people can be trusted (rank 11th).
Further exploration of our worst-ranked Social Wellbeing indicator ‘Feeling close to people in local area’ showed considerable variation across the country with the major cities scoring worst with Auckland at the top. Regional areas fared somewhat better. Younger people and NZ European New Zealanders scored lowest.
New Zealanders make choices everyday about their wellbeing. These are both personal choices as well as democratic choices about public policy and action at local and national levels. It is our vision that this index can help frame both personal choices and public policy and action in New Zealand. If it isn’t wellbeing for ourselves and others we are ultimately striving for, then what is it?
The Sovereign Wellbeing Index will continue to monitor the wellbeing of New Zealanders over the next four years. We plan to follow-up some of the participants in this nationally representative cohort to see how their wellbeing changes with time as well as continue to run this national index and benchmark indicators against European countries.