Eating fatty foods may be triggered by survival mechanism

Published on Monday 27 April 2009 22:52

THE pre-summer diet is an annual ritual for millions – as is the overwhelming desire for a bar of chocolate or a bag of crisps to undo all the good work and pile back on the pounds.

But scientists have now discovered the memory of tasty, calorie-packed treats bypasses the more sensible parts of your brain and may be a factor in bad eating habits.

The memories are triggered by a compound derived from oleic acids in fatty food and made in the small intestine.

Oleoylethanolamide (OEA) is known to send hunger-curbing chemical messages to the brain that increase feelings of fullness. High levels of OEA can reduce appetite, promote weight loss, and lower levels of cholesterol and triglyceride blood fats.

But the same compound also sets off memory consolidation, a process by which superficial short-term memories are turned into meaningful long-term ones, scientists have discovered.

As a result, the experience of eating a satisfyingly rich meal sticks in the memory. Once, when such foods were scarce, this may have been a helpful trait, motivating early humans to seek out fatty meals that enhanced their survival. But in today's world, with its abundance of high-calorie foods, it might encourage over-eating and obesity, say the scientists.

Dr Daniele Piomelli, of the University of California at Irvine in the United States, said: "By helping mammals remember where and when they have eaten a fatty meal, OEA's memory- enhancing activity seems to have been an important evolutionary tool for early humans. It was probably an important survival mechanism."

The findings are published in the journal Proceedings of the National Academy of Sciences.