Some proponents of calorie restriction argue that restricting calorie intake alone is responsible for longevity, regardless of any accompanying weight loss. However, Harvard University scientists have shown that animals who manage to stay lean regardless of their calorie intake also increase their longevity.

A hint that neither leanness or calorie restriction by themselves is the direct cause of increased longevity is supplied in the early research of Dr. Alex Carrel. A Nobel Prize winner in medicine during the first half of the twentieth century, Dr. Carrel demonstrated his method for increasing longevity in living animal cells cultivated in a laboratory dish.

Dr. Carrel showed that the fluid in which the cells floated gradually accumulated the normal toxic end-products of metabolism, cellular waste products, excreted by the cells. Periodically replacing this fluid with fresh clean fluid while providing the cells with adequate nutrients, Dr. Carrel created an environment for the cells that extended their life. Some genetic researchers point out that even a healthy cell will eventually wear out and die, but nevertheless, Carrel's research demonstrates an important principle of longevity that we can apply to our lives.

Alex Carrel's laboratory experiment is strikingly similar to the internal environment of our bodies. Just as Dr. Carrel regulated the balance between the cells' nutrient intake and the removal of excreted cellular waste, our bodies are equipped to normally function likewise. However, when the regular removal of excreted cellular waste in the laboratory cells becomes backed up, the cells are damaged due to auto-intoxication from the retained waste. Is it not possible that something similar occurs in our bodies when removal of the normal end-products of metabolism is held up and toxins begin to accumulate within the intracellular fluid within the cells, as well as within the extracellular fluid that surrounds the cells?

What would cause such a backup of toxic cellular waste in our bodies? One answer could be a lifestyle that reduces our normal excretory function, especially a lifestyle replete with overeating.

The metabolism of a healthy body consists of two parts: the breakdown and excretion of cellular waste (catabolism) which the body normally keeps in balance with the assimilation of nutrients, water and oxygen that buildups and restores the body's cells (anabolism). However, when more food comes into our bodies than can be completely metabolized and eliminated, a net gain in bodyweight in the form of body fat and toxic waste occurs as surplus material accumulates. Our bodies' excretory function lags behind. However, excretion is stepped up during the process of losing extra weight through calorie restriction or fasting. Accumulated deposits of excess waste and body fat are thus eliminated and cellular life is renewed, much as in Alex Carrel's laboratory dishes when the old fluid that was filled with waste is wiped away and is replaced with clean fluid. 

In his research on fasting, Dr. Anton J. Carlson, a physiologist at Chicago University stated: "It is possible that the striking beneficial aftereffects of prolonged fasting may be due to the fact that the non-essential tissue used up in starvation may include abnormal accumulations of some intermediary products of metabolism."

In addition to overeating, overstressing the body beyond full recuperation redirects energy away from our normal excretory function, thereby causing excretion to lag which results in an accumulation of toxic end-products of metabolism.

It should be pointed out that the colon, although an organ of the excretory system, never comes in direct contact with the intracellular and extracellular fluid where cellular excretion occurs. The colon's role includes receiving and voiding cellular waste already processed and eliminated through the other excretory organs, such as the kidneys and liver. Therefore, an effort to stimulate removal of waste at the cellular level through colonic treatments is pointless.

In conclusion, it seems that calorie restriction and leanness, although associated with longevity, do not directly cause it. Rather, calorie restriction and leanness facilitate the removal of toxic accumulations of cellular waste which increases cellular longevity. Regardless of the exact cellular mechanism by which it works, one thing for sure is that weight loss, either through fasting or calorie-restricted diets, increases longevity. Longevity is thus another benefit added to the list of health and wellness benefits offered in a sound weight management program, like The Body Fat Guide.

Click for more information