The connection between restricting food intake and improved health is well known to science. For decades, researchers have documented increased resistance to physiological aging, age-related disease, and increased longevity by using calorie restriction (CR).

The correlation that exists between CR and improved health has been demonstrated in the laboratory for 75 years. Mice, yeast, worms, flies and other species have conclusively been shown to live longer – much longer in some cases – through caloric restriction. Today, a growing body of evidence indicates the benefits of dietary restriction extends to humans, as well.

Fasting is the complete abstinence of food, with durations ranging from a few hours to a few days. Although some people restrict their diet to 50-100 calories a day for 3 or 4 days, these extremes are unnecessary; the health advantages of CR are available with a more moderate approach. Models known as alternative-day or intermittent fasting are also effective ways to improve and sustain physical and cerebral health without extreme deprivation of food.

When such obvious health benefits result from reducing the amount of calories consumed, any argument about whether CR can actually extend one’s life is almost irrelevant: Researchers simply disagree on direct causes – the actual mechanisms. Is it the reduction in overall calories that conveys the benefits, or just the reduction of protein? These are just minor devils in the details.

That age-related diseases and disorders are significantly reduced with CR diets, is not contested. Some of the many health benefits of dietary restriction include:

Lower risk of cardiovascular disease and aneurysms.

LDL (bad) cholesterol contributes to a hardening of the arteries (atherosclerosis), the leading cause of death in the West. When blood vessels become clogged, they are unable to transport oxygen to the organs. This deprivation of oxygen to body tissue can cause not only heart attacks and strokes, but also premature aging. Fasting lowers the LDL cholesterol in the blood, which improves cardiovascular health.

CR also lowers blood pressure significantly: another improvement that not only lowers the risk of heart disease, but also damage to arteries, and aneurysms.

Reduced insulin levels and IGF-1

Elevated insulin levels are a two-fold problem, especially as relates to weight-loss. High levels can cause fat-retention, while at the same time causing muscle-depletion.

The body’s defense against low blood sugar is to “burn” stored body fat. However, with high levels of insulin this process is impeded, and the body will begin to “burn” muscle tissue instead – exactly the opposite of what is usually needed.

IGF-1, or insulin-like growth factor, is strongly correlated with the aging process. Although the exact mechanisms are unknown, experiments have shown IGF-1 reductions can slow the degenerative effects of age and reduce cancer risks (because it helps to regulate cell division/growth, perhaps). IGF-1 levels are markedly reduced in studies of CR, and its effects on longevity. This confers a strong anti-aging benefit as well as lower cancer risks.

Decreased diabetes and obesity risks:

CR diets effectively manage obesity. Studies have shown a significant weight reduction in randomized trials. From an article published in Annals of Internal Medicine:

Patients treated under medical supervision using a very-low-calorie diet (400 to 800…[calories per day]) lose approximately 20 kg (44 pounds!) in 12 to 16 weeks and maintain one half to two thirds of this loss in the following year.  — Thomas A. Wadden, PhD, Center for Health and Behavior, Syracuse University.

Obesity and diabetes are strongly connected. Weight loss inevitably leads to a reduced risk of diabetes; the amount of weight lost will directly affect the percentage of decreased risk.

Other advantages of a CR diet include a lower risk of Alzheimer’s and Parkinson’s diseases, as well as delayed onset of physiological aging and multiple age-related health conditions

Although there has been a contentious debate surrounding CR diets and their ability to extend human life, the animal studies indisputably prove that longevity is extended using CR – in some mammals the increase in lifespan was upwards of 30%. The above benefits, also widely recognized, clearly convey a significant health advantage, which renders the entire debate moot. If you want to optimize your health, reduce the risks of age-related illnesses, and perpetuate overall good health, consider a calorie restricted diet.