FOR MORE than 60 years, scientists have known that animals that eat less live longer, healthier lives. And now new research presented here Thursday shows that people who follow a low-calorie, yet nutrient-rich diet, also lower their risk factors for serious disease. With only 2.5 years of follow-up, the data still aren’t in on whether study participants actually added years to their life spans. But men and women “on a low-calorie, high-quality diet experienced the same broad physiological improvements that we see on animals on such diets,” said study author Dr. Roy L. Walford, professor of pathology at the University of California, Los Angeles. “Therefore, there is every reason to believe that the other effects seen in animals – retardation of aging, life extension and a sharp incidence in risk of disease – also apply to humans.”
The new findings grew out of the experimental study known as Biosphere 2, in which four men and four women, including Walford, sealed themselves inside a closed ecological area from 1991 to 1993. The enclosure comprised seven biomes: rain forest, Savannah, ocean, marsh, desert, farm land and a habitat for humans and domestic animals. All organic materials, all water and nearly all air were recycled, and virtually all food was grown inside. Over the course of their stay, the men lost an average of 18 percent of their total body weight; women, 10 percent. Most of the weight loss occurred during the first six months of their stay, Walton reported. Average blood pressure decreased an average of 20 percent.
And indicators for diabetes – glucose, insulin and glycated hemoglobin – dropped about 30 percent. Cholesterol was lowered from an average of 193 to 123, and triglycerides also improved, Walton reported at the annual meeting of the American Association for the Advancement of Science. WHAT IS A LOW-CALORIE DIET? So just what is a low-calorie diet? “On average, about 1,800 a day,” Walford says, “but coupled with intense physical activity to burn off those calories.” During their stays in the Biosphere, participants exercised vigorously six days a week. Also, it’s not just a matter of eating less and working out more, he stressed. “If you took the average American’s diet and just lowered it, to total 1,800 calories a day, most americans would end up starving themselves nutritionally.” rather exclusively, vegetarian, he said.