The Wiley Protocol

Link: http://www.thewileyprotocol.com

There are a few behavioural ecologists working in Bolivia who have found that wild spider monkeys control their diets in a similar way to humans. These monkeys tightly regulate their daily protein intake, so that it stays at the same level regardless of seasonal variation in the availability of different foods, rather than simply trying to maximize their daily energy intake.

Up until now it was thought humans' eating patterns originated in the Palaeolithic era (between 2.4 million and 10,000 years ago). Tight regulation of daily protein intake is known to play a role in the development of obesity in humans, so this research suggests that the evolutionary origins of these eating patterns in humans may be far older than suspected.

Dr. Annika Felton followed 15 individual monkeys (7 adult males, 8 adult females), conducting continuous observations of the same animal from dawn to dusk, and following each of the monkeys for at least one whole day a month. She recorded everything they did and ate, for how long and she counted every fruit and leaf they ate when possible, then collected samples of what they had eaten from the actual trees the monkeys had chosen. The samples were then dried and sent to the laboratory in Australia where they were analyzed for their nutritional content.

"We found that the pattern of nutrient intake by wild spider monkeys, which are primarily fruit eaters, was almost identical to humans, which are omnivores, . What spider monkeys and humans have in common is that they tightly regulate their daily protein intake,” said Felton. “They appear to aim for a target amount of protein each day, regardless of whether they only ate ripe fruit or mixed in other vegetable matter as well.”

Tight protein regulation is the same for monkeys and humans: if the diet is poor in protein but rich in carbohydrates and fats (energy dense food) individuals will end up ingesting a great deal of energy in order to obtain their protein target, which can lead to weight gain. This 'protein leverage effect' is thought to play a significant role in the human obesity problem found in our modern western society. The monkeys maintained a stable intake of protein, by consuming large amounts of carbohydrates and fats when protein content in the food was low, for instance when their diet consisted entirely of ripe fruit, and consumed far fewer carbohydrates and fats when feeding on items rich in protein.

The results suggest that an adjustment of the nutritional balance of diets as a means to manage human obesity might similarly be an option for mitigating obesity in captive primates.