New study found that calorie-restricted diet may not make monkeys live longer

Those who stick to calorie-restricted menu because they believe that in this way they’ll live longer may be disappointed since diets don’t seem to result in longevity. At least as far as monkeys are concerned, according to a National Institute of Aging study published Wednesday in the journal Nature. However, those of us who cannot put up with the periodic hunger pangs, chills, and skinny body, characteristic of people who have reduced their calorie intake, may feel relieved.

The latest study certainly doesn’t give us a conclusive answer to the question of whether calorie restriction will result in longevity. It actually contradicts a study conducted by the Wisconsin National Primate Research Center in 2009, which indicated that monkeys put on a calorie-restricted diet lived longer and healthier lives.

That earlier study may have had some flaws. The animals were all fed relatively unhealthy diets – they received only one-third of their calories from sugar. This means that the calorie-restricted monkeys may have been healthier and lived longer just because they had less sugar in their menu.

On the other hand, the monkeys in the new trial received 4 percent of their calories from sugar, no matter if they were on a calorie-restricted or normal diet used for comparison. All of the animals also ate fish oil and other nutrients that were lacking in the Wisconsin study, and, as a whole, they ended up weighing less, compared with the Wisconsin monkeys. The latter had more body fat.

Genetics may have also been a factor since monkeys in the two different studies came from different countries.

Some of the monkeys on the calorie-restricted diets in the latest study had some health benefits over their counterparts. Male monkeys who went on a calorie-restricted diet when they were older had lower levels of cholesterol and blood sugar. Moreover, both males and females had lower levels of triglycerides which may have protected them against heart disease.
Those monkeys who went on a restricted-calorie diet in young age didn’t enjoy these benefits, though they did had lower rates of cancer. Nevertheless, this didn’t help them live any longer.

Aging Institute director Dr. Richard J. Hodes said that the results show the complex effect calorie restriction may have on the body because it depends on a variety of factors, such as environment, nutritional components and genetics.