How we eat and source food today, and really the last one hundred years is markedly different to the entirety of human evolution spanning millions of years.
The majority of this time was spent as a hunter-gatherer where our physiology and behaviour primed a species to later dominate the planet6.
Behaviours that have moulded the physiology we see today in the western world can be seen in some of the few remaining hunter-gatherer populations like the Ache people of Paraguay or the Hadza of Tanzania. Researchers have observed men eat five pounds of fatty meat in one sitting, drinking one and a half litres of pure honey, or eating thirty wild oranges1,2,3,4. Their eating habits have been described as gluttonous. This of course makes absolute sense in evolutionary terms. In times gone by, these people would not know when the next opportunity to feast might arise and so extracted the maximum number of calories from their food possible.
The idea of eating in moderation is simply contradictory to how we survived and evolved. Had the Achè or Hadza eaten their meat, honey or oranges in 'moderation', they would have likely died 1.
Outright gluttonous behaviour can be seen across any number of animals in the wild. In fact I was in France on holiday recently with my mum and girlfriend where we went to feed the local donkeys carrot sticks. I couldn't help but notice that the donkeys would still be fighting over the carrots two weeks later had I stood there long enough giving them out!
A simple youtube search of any animal at feeding time and one will observe a frenzy, a race to consume the food with little thought for moderation. For most of our (and all animals) history, our instinctive drive to seek large amounts of fat, sugar, starch and protein were well aligned with our best interests. Guyenet (2017) describes how there was no need to count calories or feel guilty about over eating. Yet in todays world of extreme food abundance, these same primitive drives no longer serve to maintain our survival, they are at the very heart of what is killing many millions of people in the western world from obesity and obesity related disorders.
The debate over which food group (carbohydrates versus fats) is causing obesity has become redundant in line with what we now understand about weight gain and obesity. We simply eat too much. The brain that drives hunter-gatherers to gorge on calorie-dense foods because it is good for them, is the same brain that drives us to overeat in the modern world of abundance1.
What might happen if a hunter-gatherer was offered a local superstore to get his food, or if a chimpanzee could just have food delivered ad lib? Would they remain lean? *
It is unlikely that they would stop gorging until they were literally ready to pop, a feeling most of us can relate to after an 'all you can eat buffet'. One major difference between the chimpanzee and the man however is the larger human brain. This means we have another level of complexity surrounding our eating behaviours, we have a so called 'human' brain and the accompanying 'will power', or not in some cases.
*We can see chimpanzees are lean and we know hunter gatherers were lean and that it was not purely down to exercising more from detailed metabolic studies5.
A fundamental difference in the environment a chimpanzee in the wild faces and us in modern society is the frequency in which we encounter the opportunity to gorge. We are faced with a battle of will power every single time we sit down and eat. Resisting overeating is frustrating for a great many and for evolutionary reasons discussed thus far, is a deeply ingrained behaviour that will overwhelm will-power to resist it. Eating in moderation is making it difficult to fit into our jeans because its in absolute conflict with our genes.
What has changed however is not our genes, its our environment; food, cars, jobs and lifestyle.
Sure genes can have an effect, but we can't control our genes. Genetics may load the gun but environment pulls the trigger. We need to understand how we are influenced by our environment as this IS in our control1.
Whats that about a chimp brain, a human brain and a landmark (child cruelty) marshmallow study??
Luke R. Davies :)
- Guyenet, S. J. (2017). The Hungry Brain: Outsmarting the Instincts that Make us Overeat, Vermilion, Ebury Publishing, London, UK.
- Winterhalder, B. and Smith, A. E. (2000). Analyzing Hunter Gatherer Stategies: Human Behavioural Ecology at Twenty Five, Evolutionary Anthropology, 9(2), P.51-72. (Cited in REF 1 - P.95)
- Hill, K., Kaplan, H., Hawkes, K. and Hurtado, A. M. (1987). Foraging Decisions Among Achè Hunter-Gatherers: New Data and Implications for Optimal Foraging Models, Ethology and Social Biology, 8(1), P1-36. (Cited in REF 1 - P.95)
- Smith, E. A., Bettinger, R. L., Bishop, C. A., Blundell, V., Cashdan, E. and Casimir, M. J. (1983). Anthropological Applications of Optimal Foraging Theory: A Critical Review, Current Anthropology, 24(5), P.625-51. (Cited in REF 1 - P.95)
- Pontzer, H., Raichlen, D. A., Wood, B. M., Mabulla, A. Z. P., Racette, S. B. and Marlowe, F. W. (2012). Hunter-Gatherer Energetics and Human Obesity, PLUS ONE, 7. (Cited in REF 1 - P.96)
- Harrari, N. H. (2014). Sapiens: A Brief History of Human Kind, Harvill Secker, England, UK.