Scientists have known that calorie restriction, when accompanied by optimum nutrition ( also known as C.R.O.N.) can extend lifespan of animals 30 to 230 %, depending on the species. Primate studies are in process. It will be another 10 years before we known the final results, and no doubt, results will then lead to even more questions. What we do know, from major studies of centenarians already underway, is that the demographics have nothing much in common. Many centenarians are smokers, for example. They come from all over the world without a favoring any geographic location in particular. However, there are 3 consistent blood metabolic indicators of all centenarians that are relatively consistent: low sugar, low triglyceride, and low insulin. All three are relatively low for age. Among these three variables, insulin is the common denominator. The level of insulin sensitivity of the cell is one of the most important markers of lifespan.

Insulin

When we eat, the food we consume turns into sugar once inside the body. This is particularly true of carbohydrates such as potato or rice. This sugar circulates within us, and under the influence of insulin, is absorbed into the surrounding cells and tissue where it is metabolized into energy, or in the case of excessive sugar, stored for future use.

Insulin is commonly known as a hormone secreted by the beta cells of the pancreas that lowers the blood sugar by promoting their transport from the blood stream to the cell. Cells, in turn, use sugar as fuel to generate ATP, the energy currency of the body. Insulin's real purpose in our body is to help the body store excess nutrients.

When we take in excessive sugar and once the body sense that there is too much, insulin is  released to take the excess sugar out of the bloodstream and store it by converting it into glycogen. The amount of glycogen stored in the liver is small. The entire reserve cannot last more than a day of activity. Excess sugar above and beyond what can be stored as glycogen is then stored as palmitic acid, a saturated fatty acid. Now you see how excessive sugar (calorie) intake leads to extra fat in the body.