Dieting an evolutionary phenomenon?

Dieting may be in vogue now, but it's perhaps an evolutionary phenomenon.

A new study has revealed that monkeys take to dieting to shed flab in a similar way to people, a major finding which researchers claim suggests the human susceptibility to obesity might have much earlier evolutionary origins than thought.

In fact, the researchers have based their findings on an analysis of the dietary habits of around 15 Peruvian spider monkeys in the Bolivian rainforest over a period of one year, the 'Behavioral Ecology' reported.

Lead Annika Felton of Australian National University said: "We found that the pattern of nutrient intake by wild spider monkeys, which are primarily fruit eaters, was almost identical to humans, who are omnivores.

"Spider monkeys appeared 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.

This result was unexpected because, previously, ripe fruit specialists were thought to be 'energy maximisers'.

"In other words, they would aim to maximize their daily energy intake.

Our findings show this is not the case."

According to the researchers, the consequence of 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) then 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 modern western societies.

"Our results suggest 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.

Our findings are interesting from an evolutionary point of view.

"Similarity in the regulatory pattern of protein intake between distantly related species, such as humans and spider monkeys, possessing very different dietary habits, may indicate that the evolutionary origins of such regulatory patterns are quite old potentially far older than Palaeolithic era," Felton said.