Caloric Restriction Only Benefits Obese Mice: The Journal Of Nutrition

Duh.

"If you are a mouse on the chubby side, then eating less may help you live longer.

For lean mice - and possibly for lean humans, the authors of a new study predict - the anti-aging strategy known as caloric restriction may be a pointless, frustrating and even dangerous exercise...

He and Michael Forster, of the University of North Texas Health Science Center, compared the life span and caloric intake of two genetically engineered strains of mice.

The 'fat' strain, known as C57BL/6, roughly doubles in weight over its adult life. That strain benefited from caloric restriction, Sohal said.

The 'lean' strain, DBA/2, does not become obese. Caloric restriction did not extend the life of these mice, confirming previous work by Forster and Sohal...

By measuring the animals' metabolic rate, Sohal and his colleagues came to a deceptively simple conclusion: Caloric restriction is only useful when, as in the case of the obese mice, an animal eats more than it can burn off.

'Your energy expenditure and your energy intake should be in balance,' Sohal said.
'It's as simple as that. And how do you know that? By gain or loss of weight. (sic)

'The whole thing is very commonsensical.'

For humans of normal weight, Sohal strongly cautions against caloric restriction. In a 2003 study, he and Forster found that caloric restriction begun in older mice - both in DBA and leaner C57 individuals - actually shortened life span...

Sohal's study is not the first to question the allegedly universal benefits of caloric restriction. A study by Ross et al. published in Nature in 1976 ('Dietary practices and growth responses as predictors of longevity') found that caloric restriction works best in mice that gain weight rapidly in early adulthood, Sohal said."

Amazing.

Not.

BTW, if you are one of the increasingly rare humans of normal weight and you engage in Calorie restriction to lose weight, that is called starvation, anorexia, bulimia, et cetera.