Tag Archives: hunger

Low Carb High Fat Banting Diets And Appetite Regulation – A Research Area Of Complex Causation Appears To Have Brought Out A Veritable Mad Hatters Tea Party Ensemble

Perhaps one of the astonishing things I have read in my career to date was a recent Tweet apparently written by my own previous lab boss of University of Cape Town days, now many years ago, Professor Tim Noakes. The text of this tweet included ‘Hitler was vegetarian, Wellington (Beef), Napoleon insulin resistant – Did LCHF determine future of Europe’. Tim has, in the last few years, endorsed the Low Carb / High Fat (LCHF) ‘Banting’ Diet as the salvation and ‘holy grail’ of healthy living and longevity, and appears to have recommended that everyone from athletes to children should follow the diet. As part of this diet, if I have heard / read him correctly, sugar (carbohydrate) is the ‘great evil’ and has an addictive capacity, our ancestors lived on a diet high in fat and low in carbohydrates and were as a result, according to Tim, more healthy than us contemporary folk, and our current diabetes and obesity epidemics are linked to an increase intake of sugar (but not fats, proteins or simply an absolute increase in caloric intake / portion size) in the last few decades, related to a variety of factors. All this has been astonishing to me, given that for many years when I worked in Tim’s lab, he was a strong proponent of carbohydrates / sugars as the ‘ultimate fuel source’ and wrote extensively on this, and we did a number of trials examining the potential benefits of carbohydrates which were funded by sugar / carbohydrate producing companies. While anyone can have a paradigm shift, this is one of great proportions, and given that I worked closely with Tim for a number of years (we have co-authored more than 50 research papers together, mostly in the field of activity regulation mechanisms), I have found this one, and some of the statements like in the Tweet above, to be, put conservatively, astonishing. So perhaps it would be interesting to look at some of the points raised by the folk that champion the LCHF diet and whether they have any veracity.

Firstly, one of the basic tenets of the diet is that our ancestors in pre-historic times used to use a LCHF diet and were as a result healthier because of it. Of course it is almost impossible to say with any clarity what folk ate beyond a few generations back, given that we have to rely in the period since writing started on folks written observations of what they ate, and before that, on absolutely no empirical evidence at all, apart from sociological speculation. The obvious counter-argument is that the life span has increased dramatically in the last few centuries, so while mortality rates are always multifactorial, to say that a diet used in the ancient past was beneficial is clearly difficult to accept when folk died so much younger than they did today, or that they were more healthy or lean in pre-historic days. As pointed out by Professor Johan Koeslag in my medical training days, based on the figurine the Venus of Willendorf, created in 24000-22000 BC, which depicted a female who was obese, it is as likely that folk back then were obese as it could be that they were thin. But the point is that to make any argument based on hypotheses of what was done in ancient times is specious, as we just cannot tell with any certainty what folk ate then, and it is likely that folk in ancient times ate whatever they could find, whether it was animal or plant based, in order to survive.

Based on this ‘caveman’ ideal, as nebulous as it is, the LCHF proponents have suggested that it is more ‘natural’ for the body to ‘run’ on a low carbohydrate diet, and Tim has suggested that athletes will perform better on a LCHF diet. But perhaps one of the best studies that would negate this concept was performed by my old friend and colleague, Dr Julia Goedecke, of which both Tim and I were co-authors. Julia looked at what fuels folk’s metabolism naturally ‘burnt’ as part of their metabolic profile, and found that there were some folk who were preferential ‘fat burners’ (and would perhaps do well on a high fat diet), some who were preferential ‘carbohydrate burners’ (and would perhaps do best on a high carbohydrate diet) but the large majority of folks were ‘in between’, and burnt both carbohydrates and fats as their selected fuel. If you are a ‘fat burner’ and ate carbohydrates, you may run into ‘trouble’, as equally if you are a ‘carbohdyrate burner’ and ate fats you may run into trouble similarly, but again, most folk ‘burn’ a combination of both, and the obvious inference would be that most folk would do best on a balanced diet (and of course without huge lifelong cohort studies one cannot say what ‘trouble’ either group will run into health-wise without such data).

It has also been suggested by Tim and the LCHF proponents that sugars / carbohydrates are highly addictive, and it is specifically the ingestion of this particular food source that has led to increase levels of obesity and health disorders such as type 2 diabetes in the last few decades. But, absolute caloric intake has increased over the last few decades, so a simple increase in portion sizes and overall food ingestion should surely be a prime suspect in the increase levels of obesity described. It’s likely also that high fat foods are also potentially as ‘addictive’ as sugars / carbohydrates are, if they are indeed such, and folk may also be as likely to be addicted to eating per se, rather than specifically addicted to one food type of the food they eat. The causes of an increase in appetite and the sensation of hunger is an incredibly complex field – a hundred years ago it was apparently suggested that when the walls of an empty stomach rub against each other, it causes the sensation of hunger to be stimulated. But, we have more understanding now of these processes (though still a lot to learn), and the signals controlling hunger are incredibly complex, including hormone signallers arising from the gut (such as leptin and ghrelin) that go up to the brain (principally the hypothalamus) and which induce eating focussed behaviour and activity, and these are responsive to a wide variety of food types ingested. But even suggesting that one type of food and addiction to it is the cause of obesity is manifestly absurd, given how many other reasons could be suggested to be involved in eating patterns and food choices – for example the social aspect to eating food, the community habits of different populations of folk associated with eating patterns, and the psychological needs and issues associated with eating that go beyond simple fuel requirements and fuel dynamics, let alone genetics and innate predisposition to obesity and an obese somatotype some folk inherit from their parents. To note also that weight gain is not just related to single episodes of food ingestion, and some fantastic work from old colleagues from my time at Northumbria University, Dr Penny Rumbold, Dr Caroline Reynolds and Professor Emma Stevenson, amongst others, has shown that eating habits and weight gain are monitored and adjusted over long time periods in an incredibly complex way, by mechanisms that are not well understand, and it is in understanding these long term regulatory mechanisms that the changes in weight gain we see both in individuals and societies over time will surely be best understood, rather than ‘blaming’ one type of specific food group and its marketing to the public as a food type. As has been pointed out to me by my old (and much respected) academic ‘sparring partner’, Dr Samuele Marcora, both low carbohydrate and low fat diets can be successful in initiating weight loss – but equally, both types of diets are shown to be very difficult to maintain (as are all diets) – one so often ‘falls off’ diets because these inherent, complex food intake regulatory mechanisms are pretty ‘strong’ and perhaps difficult to change.

One of the most controversial issues is the effect of LCHF / Banting diets on either optimising or damaging health, and the jury is still very much out on this, and will be until we have big cohort long term morbidity and mortality statistics of folk on the LCHF diets for prolonged periods of time. There are a lot of studies that show that eating too many carbohydrates increases morbidity and has a negative effect on health. But there are also a lot of studies that show a high fat intake also has a negative effect on one’s health. Similarly for high caloric diets, and yet also similar increases in morbidity in diets deficient in one type of food type, or indeed, very low caloric diets. So it is also difficult to get a clear picture from scientific studies exactly what diet works or is optimal – my ‘gut feel’, to excuse the pun, would be that a prudent, balanced diet will surely offer the best alternative, though with the rider as evident from Julia’s study, that some folk will do better on a higher carbohydrate percentage diet, and some with a higher fat percentage diet. There are some other interesting confounding issues, such as what is known as the survival paradox, where folks with moderate levels of obesity do ‘better’ than their thinner counterparts in some age related disease mortality rates – particularly apparently in folks once they get over 70 years of age, when obesity may paradoxically become protective rather than pathological. A point has also been raised that there are increasing levels of people with appetite disorders and body image disorders in the last few decades too (such as anorexia nervosa, bulimia and muscle dysmorphia, amongst others), and while the genesis of these appetite related disorders is also incredibly complex, diets such as LCHF, like many other very rigidly defined diets with specific eating requirements, may be propagating the capacity for such disorders to flourish, and indeed, a number of the ‘zealots’ who ‘convert’ to such diets and stick to them ‘through thick and thin’, may have appetite related disorders and are able to ‘use’ the camouflage of sticking to a LCHF diet to ‘mask’ a latent eating disorder. I can’t comment on the veracity of this suggestion, without seeing more research on it, but my ‘gut feel’ again is that there may be something like this.

Eating patterns and dietary choices, and their relationship to health, are surely some of the most complex and multifactorial areas of research that there can ever be in science. Because of this it is so hard to find and do good science that can give a clear indication of the ‘best’ diet or eating pattern for any one person, and most science in the field concentrates on one food type or one outcome of specific food type ingestion, and makes conclusions based on their results that are well intentioned, but always succumb to the problem of the complexity of the human and social dynamics associated with what and how much folk eat, that is perhaps impossible ever to reduce to a single laboratory or even field based experimental protocols. Because of this (and the fact that people need to eat on a daily basis to survive, so in effect everyone is a ‘captive audience’ for and to information), it is a field which is susceptible to anyone ‘getting up on a soap-box’ and putting their ‘five cents’ into the debate, and with modern communication methods available to us like blogs and the social media channels currently available, these opinions can spread rapidly and be taken as ‘gospel’ in a very short period of time. When someone, whom I respected so much as Tim Noakes, and with whom I have published so prodigiously together as a co-author in the past (though not in the field of LCHF / Banting diets), starts ‘banging off’ with tweets such as the above about the future of Europe potentially being determined by folk eating a LCHF diet or not (part of me is sure that Tim, if he did write this, perhaps did so in jest, or it was written as a ‘spoof’, as it is such a ‘left field’ post), I do wonder whether the field of nutrition, and those interested in it has become something of a ‘mad hatters tea party’ (though of course I have great respect for the large majority of my nutritionist colleagues). Surely like all diets, the LCHF / Banting diet will fade away as people find it hard to stick to it, as a new diet fad is announced and takes its place, and as science ‘chips’ away at some of the astonishing claims for its veracity made by its proponents. Surely in the end a balanced diet, like a balanced anything, will ultimately prevail as the diet ‘champion’. Until then, March Hare or Mad Hatter, whoever of you is pouring the tea, can I please have two spoons of sugar in my tea. If having such prevents me from ruling Europe, or dominating the world, so be it!

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