Fewer calories, longer life?

Previous research has shown that animals that eat 30 to 50 percent less food live significantly longer lives—sometimes up to 50 percent longer than animals fed regular diets—and have fewer age-related diseases compared to their peers. Those findings have led some people to adopt their own restricted-calorie diets in hopes of gleaning the same benefits. But there's been little evidence to date to show whether the approach works in humans the same way it does in animals.

That's why I was keen to attend a symposium titled "Calorie restriction and longevity" at the annual meeting of the Obesity Society, held October 3 - 7, 2008 in Phoenix. Among the presenters was Luigi Fontana, M.D., Ph.D., a professor at Washington University in St. Louis who, with colleagues, has been following a cohort of people who practice ongoing calorie restriction. They call themselves CRONies, for Calorie Restriction with Optimal Nutrition.

In an article published this month in the journal Aging Cell, Fontana and colleagues measured CRONies' levels of a chemical called IGF-1 (insulin-like growth factor-1). In animals, levels of IGF-1 decline by about 40 percent when calories are restricted; this reduction is believed to play a role in protecting against cancer and slowing aging. The researchers found no differences in IGF-1 levels between people on calorie restrictions and those who were not. But when they asked some of the CRONies to cut their intake of protein—also known to influence IGF-1—for three weeks, their levels of the chemical declined dramatically. The same researchers found similarly low levels of IGF-1 in vegans, even those who were heavier and had more body fat than the CRONies.

While preliminary, the findings suggest that the level of protein in the diet, not just the number of calories, may influence longevity, and that a diet rich in low-calorie, nutrient-dense plant foods may be the real fountain of youth. Indeed, people in Okinawa, Japan, generally eat this way and they live longer than perhaps any other group of humans—an average of 86 years for women, 77 for men. And they tend to face extremely low risk of the chronic diseases normally associated with aging, particularly in Western countries and mainland Japan, such as Alzheimer's disease, heart disease, and cancer.

In case you're wondering, the CRONies Fontana studied ate about 1,700 calories a day on average. They had been on a restricted-calorie diet for an average of six years. To learn more about the group, visit their Web site, www.calorierestriction.org.

—Jamie Kopf Hirsh, associate editor

Comments

[cj]

Is designer whey protien been tested by ur lab? if so is it a good product

[THE DUKE]

I sure would like to know more about restricting your protien intake and how that effects your health. I would equally be interested in any diets or nutritional plans structured around lowering IGF-1 levels. It would be awesome to have more info on these subjects.