Cut Calories, Live Longer
New research explains how eating a little less food can add years to your life.
Posted Mar 26, 2018
If you’re overweight, and especially if you’re so severely overweight you can be categorized as obese, you’re likely to benefit from shedding some pounds. And in order to stay healthy and live your best life, you probably have to cut back on calories and/or increase the amount of exercise you do on a regular basis. But science is now proving what some people have long believed, and others have suspected, to be true: Cutting calories can benefit normal-weight people as well. A collaborative study by researchers at Georgia State University, Florida Hospital and Sanford-Burnham Research Institute in Orlando, and Pennington Biomedical Research Center in Baton Rouge, Louisiana, found for the first time that a carefully-controlled, calorie-restricted diet may increase life expectancy in young, healthy adults who are not obese.
The scientists were following up on animal research performed over previous decades that found calorie restriction not only increases lifespan without chronic disease in many species, but also results in more youthful mental and physical functioning. They also looked at the few formal and informal studies that exist of people who live to be 100 years old and also people who self-practice calorie restriction with the goal of better health and longevity.
In this study, 34 non-obese male and female volunteers, with an average age of 40 (plus or minus 6 years), were placed on a calorie-restricted diet for two years. The study participants cut their calorie intake by 15 percent, lost an average of 19 pounds and as a result, their laboratory (blood and urine) tests showed significantly reduced markers of oxidative stress in their bodies that are known signs of aging. Fifteen percent isn't necessarily a drastic cut in calories. For instance, if you normally consume 2500 calories a day, cutting 15 percent means trimming off just 375 calories and sizing down to 2125 calories a day.
How does it work? Previous studies have shown that calorie restriction significantly lowers metabolic rate, or the rate at which the body uses food for energy. A lower metabolic rate indicates a more efficient use of the energy required for normal body processes, such heart rate and respiration. Since normal metabolism causes byproducts that can damage the body, this slowing down, in turn, results in less damage to DNA, preventing many age-related changes in body functions and injury to tissues and organs that ultimately lead to diseases, disorders and, possibly, an untimely death.
In a nutshell, this research takes science another step toward confirming that calorie restriction results in more efficient use of the energy you get from food, which then reduces your risk of oxidative damage to your body that causes chronic disease and ultimately leads to death. (Relate this to the fact that we eat certain foods, such as fresh fruits and vegetables and, in some cases, take certain supplements, for their antioxidant, or disease-fighting benefits.) When the metabolic process slows down, you are likely to live longer.
No special diet plan can be recommended based on these findings at this point, however, because this was a relatively small, short-term study in which no particular dietary instructions other than calorie restriction were given. Larger scale, longer-term studies that consider the quality and make-up of individual diets, and to what degree individual calorie restriction is healthful, are necessary before health experts can confirm and prescribe a specific type of diet to promote longevity. Eating a balanced diet, with foods from a variety of food groups, and watching your portion sizes (not overeating or under-eating) is still the best available advice.
Redman LM, Smith SR, Burton JH, et al. Metabolic slowing and reduced oxidative damage with sustained caloric restriction support the rate of living and oxidative damage theories of aging. Cell Metabolism. March 22, 2018.