It’s no secret that we’d benefit from eating less. Aside from targeting the raging obesity epidemic, this strategy might help us to live longer. The challenge is curbing our insatiable appetites for foods that make us fat and unhealthy. There was a time when this might have been easy, but the industrial revolution and our migration to the shopping mall have conspired against us.
When we were foraging for sustainable nutrition and a mating partner in the harsh savannahs of the Palaeolithic age, we were large, lean and healthy. We consumed game animals that were equally svelte and toned. Sugar, fat and starch were rare. Our hunter-gatherer physiques were defined by the protein we consumed and the relative absence of carbohydrates and fats. At least, compared with what we eat today. It was this protein that enabled our biological imperative, providing us with the hormones we needed to reproduce.
The agricultural revolution and increasing access to easily available carbohydrates, especially starch from grains, dramatically altered our eating habits. We reduced our consumption of animal protein, started to move less and, as a result, became smaller and less healthy. We did, however, remain lean. The industrial revolution ushered in an even greater incorporation of carbohydrates into the diet. Mass refining and transportation saw to it that grains and sugar were purchasable commodities, but only to those who could afford them, which meant being overweight was largely an affliction of the rich.
Since the two world wars, fats and carbohydrates are only a shopping trolley away and, compared with protein, relatively cheap. Our current eating patterns have spawned a world populated by slothful creatures that are large, long-lived and obese, heralding the onset of a whole range of diseases generated by our modern lifestyles. In Palaeolithic times, we consumed considerable amounts of protein. Now, our daily fare contains a miserly 15 per cent of this substance.
Protein leverage
Protein is still our go-to nutrient. It’s the essential substance we use to make our bones, muscles and sex hormones. If we accept the principle that we’re here to reproduce, protein is the pinnacle nutrient that governs the very nature of our survival. In The Nature of Nutrition, research carried out by professor Stephen J Simpson, director of the Charles Perkins Centre for the study of obesity, and professor David Raubenheimer, who heads the nutritional ecology unit at Massey University in New Zealand, describes the phenomenon of “protein leverage” whereby humans prioritise protein above all the other nutrients. We’ll eat whatever we have to in order to obtain the amount of protein we need. It also means we default to our habitual protein consumption.
This explains one of the major difficulties of the high-protein diet. Initially, diets that dictate significant increases in protein lead to weight loss because carbohydrates and fats are scaled down. However, persisting with these diets becomes onerous as they demand that we stick to the kind of protein over-consumption with which we aren’t familiar. If we are used to a diet that is only 15 per cent protein and this is massively ramped up, “protein leverage” will determine its course and ultimate failure, as we are compelled back to our original protein-eating habits. This is compounded by the fact that we are restricted to eating foods that aren’t tasty while we are surrounded by choices that are far more palatable.
Our hunter-gatherer ancestors had to live dangerously, climbing trees and dangling precariously off clifftops to obtain the honey and sweet fruits that were beyond their grasp. Fat was also rare, which led to the evolution of tastebuds that were acutely responsive to the exquisite sensation of sugary and fatty foods. Sugar and chocolate trigger the release of opioids, or pleasure chemicals, as well as dopamine, a substance made in the brain that primes the hormones necessary for sexual behaviour.
These are the dilemmas we face. Aside from those weight-loss programs that demand regular surveillance, high-protein diets are among the few regimens that generate weight loss, at least in the short term. Proteins are essential for the manufacture of our hormones, especially the hormones we need to procreate. Then there is the downside associated with proteins. In as much as it’s tough to sustain, eating too much protein isn’t good for us for a whole bunch of reasons. It increases the accumulation of free radicals, damages our DNA, even inhibiting repair of these vital structures, ultimately weakens our bones and compromises our kidneys.
Research by professors Simpson and Raubenheimer demonstrates that if we want to live longer we have to eat less protein and reduce our carbohydrates. This would lead to lower rates of cancer and would turn on the genes that perpetuate healthy DNA. Not only would this require a monumental exercise of will, as it would mean we’d have to turn our backs on those foods that give us a huge amount of pleasure, but it would also make weight loss an uphill battle. It might diminish our hormone supplies, leading to longer lives that are less robust and productive. If the study that shows Seventh-Day Adventists live longer is anything to go by, they’ve found a way to make it work.
Dr Michael Elstein is a Sydney-based anti-ageing physician and writer. He is the author of two books: Eternal Health: The Comprehensive Guide to Anti-Ageing for the New Millennium and You Have The Power: Why Didn’t My Doctor Tell Me About This?
