Restriction of energy intake from food is the most effective single intervention for preventing cancer in experimental animals. It increases the lifespan of rodents, and suppresses tumor development in mice. In addition, energy restriction can suppress the pro-cancer effects of many carcinogens in experimental animal models.

Energy restriction leads to a reduction in cell proliferation. This may directly inhibit tumor growth, and also indirectly reducing cancer development by reducing overall proliferation, thus reducing the chances for incorrect DNA replication, or by preventing damaged DNA from being replicated. Reduced metabolism results in reduced generation of reactive oxygen species, and therefore less exposure of DNA to damaging oxygen radicals.

Dietary energy restriction reduces levels of circulating IGF-1 and insulin, which are growth factors for many cells, including breast cancer. Energy restriction also decreases expression of cyclins and cyclin-dependent kinases (CDKs), and increases levels of CDK inhibitors, leading to reduced Rb phosphorylation and inhibited cell cycle progression etc. The data on energy restriction have performed in experimental animals and relevance to humans is not yet clear.

Cancer cells also require oxygen to grow. But they spread at a very fast rate.  As a result, they outstrip the supply of blood to them. This results in shortage of oxygen in cancer cells. Cancer cells need a lot of energy to grow that fast and blood oxygen does not meet their demand, consequently they ferment glucose, but this route of energy production requires very large amounts of glucose. Lack of sugar energy makes the cancer cells eat their own selves. This process is called autophagy. Some cells commit apoptosis, which is the death of cells in a natural way. A natural product that works through energy restriction is Resveratrol, present in grapes and red wine. Energy restriction may offer a powerful new strategy for treating cancer because it targets a survival mechanism used by many types of cancer. (Report from Ohio State University Comprehensive Cancer Center, Journal of Biological Chemistry 2010).