Animal experiments in the past have pointed out that overfeeding resulted in less life expectancy of the animal. Experiments with primates showed that withholding food did not compromise the health and vitality. To the contrary: the chimp lived well and even lived longer. Experiments with rodents are still very much removed from the application to humans, and to get closer to the facts, new research has enlisted the help of humans. Participants were randomized to 1 of four groups in a study that went on for half a year. The first group received caloric restriction of 25% of baseline requirement. A second group had 12.5 % caloric restriction, group three 12.5% more exercise with a structured program. A fourth group consumed a very low-calorie diet of 890 kcal until 15% weight reduction, which was followed by a weight maintenance diet.
At 6 months, fasting insulin levels were significantly reduced from baseline in the intervention groups. Core body temperature was reduced in the group with calorie restriction and the group with calorie restriction with exercise.
These findings suggest that 2 biomarkers of longevity (fasting insulin level and body temperature) are decreased by prolonged calorie restriction in humans. The metabolic rate is lowered as a result. DNA damage was also researched, and in the intervention groups (calorie restricted diets) it was lower. The 6-month study suggests, that calorie restriction may not mean deprivation, but less “wear and tear” on the metabolism.
Studies of longer duration are required to determine if calorie restriction has the capability to slow down aging in humans.
More on calorie restriction: http://nethealthbook.com/news/calorie-restriction-makes-live-longer/
Reference: JAMA. 2006; 295:1539-1548
Last edited Oct. 31, 2014