Calorie restriction is what most people call "dieting," and it is a commonly used weight loss method. Some people also believe that a long-term commitment to a nutrient-dense, calorie-restricted diet slows down the aging process and leads to a longer, healthier life. Long-term calorie restriction has been shown to lengthen the life and improve the health of laboratory animals, but there is not enough evidence to say whether a similar diet can extend the lives of humans.
History
In the 1930s, experiments performed at Cornell University found that rats who were fed a drastically reduced-calorie diet that contained all necessary nutrients lived almost twice as long as normally expected. These results led to more animal research, and monkey studies yielded similar results. Although most people are unlikely to follow such a low-calorie diet, about 3,000 researchers and practitioners have joined a group known as the Calorie Restriction Society International. Members of this group have been studied and monitored by researchers at Washington University.
Features
A calorie-restricted diet to promote longevity reduces normal total calorie intake by 20 to 30 percent. At this caloric level, practitioners expect to stay healthier and live 20 to 30 percent longer. Eating fewer calories slows down the body's metabolism, which can slow down the aging process. Calorie restriction is not considered a short-term diet but a long-term commitment to a lifestyle that includes eating low-calorie meals that are also high in nutrients. People who follow a calorie restricted diet typically eat mostly fruits and vegetables along with small portions of lean meats, poultry and fish.
Effects
Researcher Richard Weindruch, Ph.D., of the University of Wisconsin, has found that, in primates he has studied for more than 20 years, calorie restriction with nutrient supplementation has resulted in a longer lifespan with reduced incidence of heart disease, diabetes and cancerous tumors. Monkeys that follow a long-term, restricted-calorie diet look and act younger than they are.
Significance
A calorie-restricted diet results in weight loss when dieters reduce their intake to 1,400 or 1,500 calories. Whether or not a calorie-restricted diet will also result in a longer, healthier life in humans has yet to be determined. Limited research has shown, however, that people who follow a calorie-restricted diet have lower blood pressure and blood cholesterol levels as well as a reduced percentage of body fat, normalized blood sugar and improved memory, according to the Mayo Clinic.
Warning
It is important to consult a doctor before embarking on a long-term, calorie-restricted diet because there may be health risks involved. Possible risks include include anemia, dizziness, hormonal changes, menstrual irregularities, reduced bone density and loss of muscle mass. Nutrient deficiencies can occur on low-calories diets unless they are very well planned. A doctor may recommend vitamin or mineral supplements to offset any deficiencies.
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