Gorillas stay lean by following Atkins
New research on the eating habits of gorillas may provide a vital clue as to why modern humans are becoming increasingly obese.
Scientist David Raubenheimer studied gorillas in Uganda’s Bwindi Impenetrable National Park, who seasonally gorge on protein to meet their needs for carbohydrates and fats.
Prof Raubenheimer noticed the primates were doing the opposite of what many overweight humans do in over-eating carbohydrates and fats to attain enough protein.
His study, published in the latest issue of the journal Biology Letters, found gorillas ate a high protein diet, supplemented with fruits.
In the four months of the year when fruits were freely available, the apes ate a diet which provides 19 per cent of energy from protein, roughly similar to the protein requirements of humans.
However, during the eight months of the year when the fruits become scarce in their highland habitats, the primates compensated by gorging on protein-rich leaves, eating a diet which provided 30 per cent of their energy needs from protein, similar to the popular weight-loss Atkins regime.
"This provided us with a natural experiment in which we could test whether the appetite of mountain gorillas is more tightly linked to protein or non-protein energy [carbohydrates and fats]," Prof Raubenheimer said.
"If protein is more important, then gorillas stuck on the high protein diet will eat enough food to satisfy their need for protein, but in the process eat less than the required amount of fats and carbs."
"This pattern of nutrient regulation, which we call 'protein leverage', explains a lot about the nutritional biology of our own species," he says.
"It means that our intake of fats and carbs, and hence of energy, is lower when we eat a diet high in protein - which is how high protein weight loss diets, like the Atkins diet, work.
"But there is a flipside - when we eat a diet low in protein, we over-eat fats and carbs to satisfy our appetite for protein." This, says Professor Raubenheimer, may explain the dramatic rise in human obesity in recent decades.
"For a number of reasons, including the relatively high price of protein, the protein content of our diets has over the past 50 years become diluted with fats and carbs. Our craving for protein causes us to over-eat the low-protein foods, in the same way that an alcoholic would drink more low-alcohol larger to satisfy his addiction".