A two-year study that was sponsored by the National Institute of Health examined whether calorie restriction would lower risk factors associated with age-related diseases, so it extends lifespan.
The goal was to put 218 healthy men and women who were normal weight or moderately overweight on a 25% calorie lowered diet compared to their regular diet. They were given a weight loss target of 15.5% below their previous weight and asked to maintain this for the year after. The control group was asked to keep their weight at the same level over the course of the two-year study.
The actual outcome of the study showed that the calorie restricted group could only reach a 12% calorie restriction over the first year instead of the goal of 25%, but the weight loss was maintained over the course of the next year.
The outcome of the calorie restricted group was that several of the cardiovascular risk factors were changed: total cholesterol decreased by 6%, while the protective HDL was increased; blood pressure decreased by 4% and the C-reactive protein, a measure of inflammation was reduced by 47% as was insulin resistance. All of these factors are risk factors associated with heart attacks and strokes. In the case of the calorie restricted subjects all of these factors had improved simultaneously to indicate that calorie restriction was protecting them against cardiovascular disease.
What are the risk factors for heart disease? LDL cholesterol, which is a sub fraction of total cholesterol can get oxidized and form plaques and calcifications in the coronary arteries. HDL cholesterol counteracts that and protects against heart attacks and strokes. Blood pressure elevation has long been known to be a major risk factor for heart attacks and strokes. Since the mid 1990’s inflammation as measured by the C-reactive protein has been recognized to be an important marker for the development of hardening of the arteries. A 47% reduction in its baseline value is a significant finding and all of this was achieved by only 12% calorie restriction.
Many authorities recommend having a fasting day every 1 or 2 weeks where you restrict your calories. Most individuals will find these measures not too difficult, whereas longer fasts are not that easy. This one-day of fasting every one or two weeks can make a difference for your health!