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The "skeleton in the hospital closet" was the phrase used to call attention to the unrecognized and untreated malnutrition found in US hospitals (1). The sequelae of hospital malnutrition are […]

Statistics confirm that obesity remains a major health problem in the Unites States; of adults aged 20 to 74 , 34 million (25.6%) are 20% or more above desirable body [...]

Larson-Meyer, D. Enette, Bradley R. Newcomer, Gary R. Hunter, James E. McLean, Hoby P. Hetherington, and Roland L. Weinsier. Effect of weight reduction, obesity predisposition, and aerobic fitness on skeletal muscle mitochondrial function. Am. J. Physiol. Endocrinol. Metab. 278: E153-E161, 2000.--We used [sup.31]P magnetic resonance spectroscopy to measure maximal mitochondrial function in 12 obesity-prone women before and after diet-induced weight reduction and in 12 matched, never-obese, and 7 endurance-trained controls. Mitochondrial function was modeled after maximum-effort plantar flexion from the phosphocreatine recovery time constant ([TC.sub.PCr]), the ADP recovery time constant ([TC.sub.ADP]), and the rate of change in PCr during the first 14 s of recovery (OxPhos). Weight reduction was not associated with a significant change in mitochondrial function by [TC.sub.PCr], [TC.sub.ADP], or OxPhos. Mitochondrial function was not different between postobese and never-obese controls by [TC.sub.PCr] [35.1 [+ or -] 2.5 (SE) vs. 34.6 [+ or -] 2.5 s], [TC.sub.ADP] (22.9 [+ or -] 1.8 vs. 21.2 [+ or -] 1.8 s), or OxPhos (0.26 [+ or -] 0.03 vs. 0.25 [+ or -] 0.03 mM ATP/s), postobese vs. never-obese, respectively. However, [TC.sub.ADP] was significantly faster (14.5 [+ or -] 2.3 s), and OxPhos was significantly higher (0.38 [+ or -] 0.04 mM ATP/s) in the endurance-trained group. These results suggest that maximal mitochondrial function is not impaired in normal-weight obesity-prone women relative to their never-obese counterparts but is increased in endurance-trained women. nuclear magnetic resonance; skeletal muscle; oxidative phosphorylation; endurance training

The purpose of this study was to objectively compare the difficulty and determine the contribution of strength and muscle mass to the performance of physical tasks of daily living in a group of younger and older women. A cross-sectional design was used. Volunteer participants were from the community of Birmingham, AL; there were 21 older (aged 60-75 years) and 20 younger (23-34 years) healthy women in the study. Subjects were matched for height and weight. Their testing included total and regional body composition evaluation by use of dual-energy x-ray absorptiometry, isometric strength tests of elbow flexors and knee extensors, and integrated electromyography (IEMG) evaluation while the subjects were standing from and sitting into a chair, and while they were carrying a small load (weight relative to strength). A two-way analysis of variance and a two-way analysis of covariance with repeated measures, Pearson product correlation, and first-order partial correlations were used to analyze the data. A significant inverse correlation was observed between age and isometric strength of both the knee extensors and elbow flexors. Adjusting for upper leg lean tissue did not change the significant inverse correlation between age and knee extensor strength. However, after an adjustment for arm lean tissue, there was no significant correlation between elbow flexor strength and age. Older women experienced significantly greater difficulty in standing than younger women as measured by quadriceps normalized IEMG (i.e., IEMG during task/IEMG during maximum isometric strength test). This difference persisted even after the covariate upper leg lean tissue was added to the model. No significant difference was observed between younger and older women for difficulty (biceps normalized IEMG) during the carry task after the covariate arm lean tissue was added to the model. The older women in this study had less strength in the knee extensors and experienced greater difficulty standing from a chair than the younger women, even after the covariate upper leg lean tissue was added to the model. This suggests that other factors, in addition to loss of lean tissue, contribute to the age-related decline of muscular strength and the ability to perform tasks with the legs. In contrast, although elbow flexor strength declined, this appeared to be largely due to decreased arm lean tissue mass.

The metabolic equivalent (MET) is a widely used physiological concept that represents a simple procedure for expressing energy cost of physical activities as multiples of resting metabolic rate (RMR). The value equating 1 MET (3.5 ml O2μkg-1μmin-1 or 1 kcalμkg-1μ-1) was first derived from the resting O2 consumption (Vo2) of one person, a 70-kg, 40-yr-old man. Given the extensive use of MET levels to quantify physical activity level or work output, we investigated the adequacy of this scientific convention. Subjects consisted of 642 women and 127 men, 18-74 yr of age, 35-186 kg in weight, who were weight stable and healthy, albeit obese in some cases. RMR was measured by indirect calorimetry using a ventilated hood system, and the energy cost of walking on a treadmill at 5.6 km/h was measured in a subsample of 49 men and 49 women (26-45 kg/m²; 29-47 yr). Average Vo2 and energy cost corresponding with rest (2.6 ± 0.4 ml O2μkg-1μmin-1 and 0.84 ± 0.16 kcalμkg-1μh-1, respectively) were significantly lower than the commonly accepted 1-MET values of 3.5 ml O2μkg-1μmin -1 and 1 kcalμkg-1μ,-1 respectively. Body composition (fat mass and fat-free mass) accounted for 62% of the variance in resting Vo2 compared with age, which accounted for only 14%. For a large heterogeneous sample, the 1-MET value of 3.5 ml O2μkg-1μmin-1 overestimates the actual resting Vo2 value on average by 35%, and the 1-MET of 1 kcal/h overestimates resting energy expenditure by 20%. Using measured or predicted RMR (ml O2μkg-1μmin-1 or kcalμkg-1μ-1) as a correction factor can appropriately adjust for individual differences when estimating the energy cost of moderate intensity walking (5.6 km/h). [ABSTRACT FROM AUTHOR]

This article presents a case report of an individual who developed a pattern of self-induced vomiting subsequent to gastroplasty surgery for morbid obesity. A description of the history, symptomatology, and disordered eating pattern is provided along with the clinical outcome from a cognitive-behavioral intervention. The results are discussed with regard to the need for future evaluation of eating behavior patterns in postgastroplasty patients. It was concluded that the syndrome is similar in many respects to the bulimic pattern observed in normal weight females. [ABSTRACT FROM AUTHOR]

Three major factors modulate body weight: metabolic factors, diet, and physical activity, each influenced by genetic traits. Despite recent advances in these areas, the prevalence of obesity in Westernized societies has increased. In contrast to monogenic animal models and rare human genetic syndromes, predisposition to common forms of obesity is probably influenced by numerous susceptibility genes, accounting for variations in energy requirements, fuel utilization, muscle metabolic characteristics, and taste preferences. Although recent increases in obesity prevalence cannot be explained by changes in the gene pool, previously "silent" genetic variants may now play important permissive roles in modern societies. Available data suggest that variations in resting energy expenditure, thermic effect of food, and fuel utilization exist but, by themselves, are unlikely to explain the onset of obesity. Regarding diet, the best available trend survey data indicate that fat and energy intake have fallen, in this and other Westernized countries. Diverging trends of decreasing energy intake and increasing body weight suggest that reduced physical activity may be the most important current factor explaining the rising prevalence of obesity. Subsistence in modern societies requires extreme adaptations in previously useful energy-conserving diet and exercise behaviors. Recognizing the difficulties in sustaining energy-restricted diets in the presence of fast foods and social feasts, the current trend toward increasing body weight is not likely to be reversed solely through recommendations for further reductions in energy intake. In all likelihood, activity levels will have to increase in response to an environment engineered to be more physically demanding. [ABSTRACT FROM AUTHOR]

Compares changes in diet and physical activity with trends in body weight and obesity prevalence, using large survey studies representative of the US population. Average fat intake; Average total daily calorie intake; Association of reduced fat intake and calorie intake and frequent use of low-calorie food products with a paradoxical increase in the prevalence of obesity.

Evaluates the separate effects of energy restriction and weight reduction on the hemodynamic and neuroendocrine status in obesity-related hypertension. Negative factors during energy restriction; Factors which showed no consistent response to changes in energy intake; Unchanged body fat pattern.