Washington: Diets can strongly influence longevity and reproductive success throughout the animal world, but work differently in males and females, according to a new study.

Males live longer and have the greatest reproductive success with a diet that favours carbohydrates to protein by 8:1, whereas females have greatest success when the ratio is just 1:1.

Given a choice, however, females eat only a little more protein than males.

The shared ability to sense and choose food dooms both males and females to eat a diet that is a compromise between what is best for each sex, the study has contended.

In other words, gender plays a major role in determining which diet is better suited to promoting longer life or better reproductive success.

Traits that benefit males are costly when expressed in females and vice versa.

This conflict may have implications for human diet, aging and reproduction, said the scientists behind the study.

"When it comes to choosing the right diet, we need to look more closely to the individual, their sex and their reproductive stage in life," said Rob Brooks of University of New South Wales, who led the study.

"It may be, for example, that women in their child-bearing years need a different diet to those who are post-menopausal," said Brooks.

"It also underlines the important lesson that what we want to eat or, if you like, what we're programmed to eat, is not necessarily best for us," he wrote in the latest issue of the journal Current Biology.

The long-term study focussed on Australian black field crickets and has discovered that the lifespan of both males and females is maximised on high-carbohydrate, low-protein diets.

"Male and female crickets maximise their fitness on different diets," said UNSW's Alexei Maklakov, study's co-author. "Despite that, the dietary preferences of the sexes are very similar."

Instead of selecting foods in a sex-specific manner, males and females select 'intermediate' diets that are less than optimal for both sexes. IANS