Keeping one's weight under control is considered to be the most practical step in prolonging the life unrestricted by onset of life-threatening health disorders. BMI and Obesity find mention in practically all references touching on the subject of longevity. Going beyond the desired goal of weight control, man is becoming more ambitious or rather 'greedy' to cling on to the Mother Earth, if not permanently but at least for a few years more than what is expected. Use of appetite suppressant by over weight people, to reduce calorie intake and thus control body weight is now being tried to prolong life amongst, other wise, normal healthy persons. The clue is provided by the findings by many studies that in rodents and some primates deliberate restriction of calorie intake enables them to extend their life span by as much as 40%!.
'Calorie restriction' (CR), according to experts, is a strategy for 'extending' healthy life, evolved based on 20 years of studies on animals which gained life extension, as much as 40%. CR is claimed to confer other benefits that include lowering the risks of most degenerative conditions of aging, reducing other risks like DNA damage, enhanced cleaning up of cells, enhancing DNA repair, protecting against aging of the heart, slowing down the deterioration in the immune system, restraining the development of Alzheimer's disease, arresting stem cell decline, reducing inflammation and checking muscle degeneration. Yeasts, fish, rodents,dogs and primates have all achieved extended life span to varying degrees, though limited studies reported on humans are still inconclusive. One of the examples cited to support the effectiveness of CR concept is the population in Okinawa, Japan which boasts of high numbers of long surviving people who habitually consume only 80% of daily food requirement as a part of their traditional eating practice.
The mechanism of slowing aging through CR is not well understood but some believe that it decreases the insulin levels thereby "upregulating autophagy". Contrary to this, studies using Sirt1 protein for longevity, scientists found the insulin levels in their studies increased significantly creating complications while Klotho protein, another longevity aid, produced lesser insulin creating diabetic like conditions. Unless the precise mechanisms of various anti-aging approaches are known, wide scale practice of such systems is ruled out. But calorie restriction is still an option, if not for longer life span but at least for a more healthier life on which there is a near unanimity amongst the scientists. Perceptions differs only as to how much restriction of calorie intake must be practiced to get maximum benefits from such a regime in to day's world where over-weight and obesity are endemic..
Antagonists of calorie restriction approach dwell on the fact that results of animal studies cannot be extrapolated on humans and the benefits of CR are far less than what is claimed. While rodents achieved 40% life span extension on CR, humans, it is claimed, can never expect to get more than 7% increase in life expectancy at practical levels of CR. Even in animal studies many aberrations were noticed such as undesirable changes in behavioral pattern, emission of foul body odors, irrational irritability, greatly reduced fertility, unbearable hunger pangs and greatly lowered energy levels incapable of carrying many normal activities. Added to this confusion some studies report that CR is effective in slowing down aging only in obese mice and normal healthy ones do not benefit at all.
CR to be effective must be practiced when young and people at the fag end of their life cannot get benefit through this diet restriction technique. If that is so it raises many questions that are legal, moral and ethical. Which mother will agree to restrict food to her child during the early stages of growth? Is it morally right to deny foods to the children when they are growing fast during the childhood? Will the practice pass legal test regarding the rights of a child before reaching adulthood? Will some one sacrifice one's quality of life to get a few extra years on this planet? Will it not be better to live healthy for some time than living with diabetes for long time? Industry has to be weary about entering into such a field with future repercussions about the possible impact on society.