Calorie Restriction Vs. Exercise For Longevity

According to some authorities, caloric restriction is the only approach that has been consistently shown to increase lifespan across a wide range of species. Interest in the concept of caloric restriction to expand human life expectancy has led to much speculation and research with decidedly mixed results.

Exercise With Weight Loss

Exercise with weight loss produced a greater reduction in body fat than did caloric restriction or exercise without weight loss in a study published in the 2009 "Journal of Clinical Endocrinology and Metabolism." The study sought to compare the relative merits of exercise and caloric restriction on insulin resistance in obesity. Suppression of glucose production was almost three times greater in exercise with weight loss, while insulin sensitivity was similarly affected by exercise with weight loss and caloric restriction.

Lean Muscle Mass

The separate and combined effects of caloric restriction and exercise on body fat reduction were tested in a study published in the July 2010 "Nutrition Review." Participants who exercised without caloric restriction had modest body weight and the least amount of loss of lean muscle. Among those who used caloric restriction alone, 81 percent lost 15 percent or more in muscle, while 39 percent of the group that used both exercise and caloric restriction lost at least 15 percent of body weight as muscle. The researchers concluded that exercise is helpful at preventing the wasting of muscle tissue with age, which contributes to longevity by preserving function and preventing falls, accidents and other incapacitating events.

Caloric Restriction

Caloric restriction without exercise was found to increase longevity in a study published in the August 2010 "Interdisciplinary Topics in Gerontology." The study, a review of previously published research, cited work that showed that, while exercise in rodents was able to confer certain health benefits, it did not result in increased lifespan. The researchers feel that ongoing long-term caloric restriction data in humans is showing close parallels with the data for rodents and primates and predict similar results for humans.

Oxidative Stress

Increased oxidation in cells may actually extend lifespan instead of shorten it, according to a study published in the June 2010 "Experimental Gerontology." An adaptive response within the mitochondria, the energy producing part of cells, leads to increased stress resistance that ultimately translates to overall decreased oxidative stress and increased longevity. This effect may occur in both caloric restriction -- which causes stress from markedly reduced glucose metabolism -- and exercise because it increases metabolism and, therefore, cellular waste production. Additionally, the researchers concluded that use of antioxidants impairs this function in cells and reduces longevity.

Coronary Heart Disease

A one-year study comparing the effects of fat loss by caloric restriction vs. fat loss by exercise on risk of coronary heart disease published in the July 2007 "American Journal of Physiology, Endocrinology and Metabolism" found substantial benefits from both. The study, which used 48 non-obese participants, reported a 14-pound body fat loss through caloric restriction and a 10-pound body fat loss with exercise. Additionally, both methods produced similar reductions in most of the major coronary heart disease risk factors known to impact longevity, including plasma LDL-cholesterol, total cholesterol/HDL ratio and inflammation.