Per capita caloric intake in the United States has not increased significantly in the past 75 years, but energy expenditure has decreased. As a result, average body weight and prevalence of obesity have increased. Paralleling this increase in body weight has been an increase in longevity. Minor obesity, therefore, is not related to increased mortality unless the patient has an underlying disease such as diabetes mellitus, hypertension, or hyperlipemia. Patients with these disorders or with a body weight in excess of 20% of the ideal will benefit most from aggressive therapy for obesity.
The publication of two books on the relationship between dietary restriction and aging has been taken as an opportunity to write a critical review on this field. The content of the two books is summarized and the implications of the major conclusions reached by the authors are appraised. It is concluded that dietary restriction should be more widely studied by gerontologists because of the light it throws on 'clocks' of aging, error detection and repair systems, and the possibilities of devising pharmacological control of these systems.
Anorexia nervosa was explored as the possible expression of an aberration of the processing of information which ordinarily has value in life protection or extension. Each of 6 areas was briefly reviewed, and noted to have the potential for failure to balance 2 or more factors. Anorexia nervosa may prove to be a psychiatric disorder in which there is altered handling of signals which otherwise are useful in survival/longevity.
Through thousands of years of starvation and poor nutrition, the human body has become adept at storing scarce nutrients. Today, in the United States and Canada particularly, the combination of sedentary habits and excessive intake of calories is imposing a dual burden on a physiologic system that is ill-equipped to handle it. Unable to rid itself of calories, the body's only defense is to store them all. The end result is obesity, with all its deleterious effects on health and longevity.
Data from several studies are presented which suggest that the traditional Greek diet still exists in several parts of Greece and several segments of the population. The most profound changes in dietary intakes in recent years concern the increase in the consumption of meat and the decrease in the consumption of pulses.
This paper reviews definitions of obesity and evidence concerning risk factors for becoming obese. Modifiable aetiological factors, including diet and physical activity, are described, and possible interactions with genetic predisposition are addressed. The impact of obesity on health and quality of life is then considered. Although epidemiological studies have not observed linear associations between increasing weight-for-height and decreasing longevity, there is a consensus that excess mortality occurs at extremely high body mass index values.
Interactions between nutrition and the ageing process are a fascinating field of research. The assessment of the nutritional status is an important part of medical examination. Generally it is assumed that energy intake and energy expenditure decrease with age. In fact they vary widely and are very different in healthy, in sick or in institutionalized elderly. Nutritional requirements depend on many social and physiological factors in the free-living elderly population. Surveys indicate that dietary requirements are qualitatively grossly comparable to those in middle-aged adults.
Restriction of energy intake (ER), without malnutrition of essential nutrients, has repeatedly been demonstrated to increase longevity in rodents. In the antioxidant theory of aging the lack of balance between the generation of free radicals and free radical scavenging was thought to be a main causal agent, in the aging process. From this point of view the antiaging effect induced by ER might be due to the lower rate of free-radical production and related damage induced by a lower metabolic rate. The antiaging effects of ER might also occur in humans.