Eat less, live longer?Six months of calorie restriction
Calorie restriction or Caloric restriction (CR) is the practice of limiting dietary energy intake in the hope that it will improve health and retard aging. , with or without exercise, lowered two signs of aging in overweight Overweight Refers to an investment position that is larger than the generally accepted benchmark. Notes: For example, if a company normally holds a portfolio whose weighting of cash is 10%, and then increases cash holdings to 15%, the portfolio would have an overweight men and women. Researchers assigned 48 healthy, sedentary sedentary /sed·en·tary/ (sed´en-tar?e) 1. sitting habitually; of inactive habits. 2. pertaining to a sitting posture. sedentary of inactive habits; pertaining to a fat, castrated or confined animal. , overweight (but not obese o·bese adj. Extremely fat; very overweight. obese characterized by obesity. obese adjective Characterized by obesity, see there; excessively fat ) people aged 26 to 49 to consume either: * 25 percent fewer calories than they needed, * 12.5 percent fewer calories plus enough exercise to burn 12.5 percent more calories than usual (typically 45 to 50 minutes of walking, running, or cycling five times a week), * a very-low-calorie diet (890 calories a day) until they lost 15 percent of their body weight, followed by enough calories to keep their weight constant, or * their usual diet. After six months, all but the usual-diet group had lower levels of fasting insulin insulin, hormone secreted by the β cells of the islets of Langerhans, specific groups of cells in the pancreas. Insufficiency of insulin in the body results in diabetes. Insulin was one of the first products to be manufactured using genetic engineering. and core body temperature, which are linked to longer life spans in animals. Furthermore, all but the usual-diet group had less DNA DNA: see nucleic acid. DNA or deoxyribonucleic acid One of two types of nucleic acid (the other is RNA); a complex organic compound found in all living cells and many viruses. It is the chemical substance of genes. damage. And their bodies adapted to the lower-calorie diets by burning fewer calories. What to do: Without longer-term studies, researchers can't tell whether calorie restriction extends life, as it does in animals. Nor do they know whether restricting calories over a long period of time has adverse effects, especially in older people. However, if you're overweight, there's no question that cutting back on calories makes sense. If you're not overweight, eating fewer calories than you need is tough to do. J. Am. Med. Assoc. 295: 1539, 2006 |
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