Search

Background: Little is known about the effect of weight change on regional lean body mass (LBM) distribution or on racial differences in resting metabolic rate (RMR). Objective: The study compared total and regional LBM patterns in white and black women after weight loss and regain and assessed the influence of regional LBM on variances in RMR. Design: Eighteen white and 22 black women who did not differ in age, weight, and height were studied 3 times: in the overweight state, after weight reduction to the normal-weight state, and after 1 y without intervention. Total and regional lean and fat masses were assessed by dual-energy X-ray absorptiometry. Results: White and black women did not differ significantly in mean (± SD) weight loss (13.4 ± 3.6 and 12.7 ± 3.2 kg, respectively) and regain (6.1 ± 5.5 and 6.4 ± 5.4 kg, respectively). Black subjects had significantly less trunk LBM and significantly more limb LBM at each time point (P < 0.05). In both races, weight regain was associated with significant increases in limb LBM (P < 0.05) but not in trunk LBM (P = 0.21). RMR, adjusted for total LBM and fat mass, was significantly higher in white women after weight loss (P < 0.01) and regain (P < 0.01). However, no racial difference was found when RMR was adjusted for LBM distribution. Conclusions: In both races, trunk LBM decreased with weight loss and remained lower, despite significant weight regain, which potentially reflected decreased organ mass. Regional LBM distribution explained the racial difference in RMR. [ABSTRACT FROM AUTHOR]

Background: Black women are at greater risk of obesity than are white women, perhaps because of their lower levels of physical activity. Objective: We compared free-living activity energy expenditure (AEE) in sedentary white and black women (in overweight and normal-weight states) and in never-overweight control subjects. Design: Subjects included 46 women (23 white, 23 black) studied while overweight and after reaching a normal weight and 38 female control subjects (23 white, 15 black). Diet, without exercise training, resulted in a mean weight loss of 13 kg and a body mass index (in kg/m2) < 25. Body composition, sleeping energy expenditure, free-living total energy expenditure, and the energy cost of activity and aerobic capacity were assessed before and after weight loss under 4-wk, diet-controlled, weight-stable conditions and in the control subjects. AEE was defined as abovesleep energy expenditure. Results: No significant racial differences in body composition, before or after weight loss, were found. After weight loss, AEE and aerobic capacity increased in the white women and decreased in the black women (P < 0.05 and P < 0.02, respectively). After weight loss, but not before, the white women had a significantly higher mean AEE than did the black women (2448 ± 979 and 1728 ± 1373 kJ/d, respectively; P < 0.05), approximating AEEs in the white (2314 ± 1105) and black (2310 ± 1251) control subjects. Conclusions: Relative to the responses of the white women to dietinduced weight loss, the black women became less fit and less physically active. Induction of a normal body weight in overweight black women appeared to produce a more obesity-prone state, favoring weight relapse. [ABSTRACT FROM AUTHOR]

Background: Although physical inactivity is believed to contribute to the rising prevalence of obesity, the role and magnitude of its contribution to weight gain are unknown. Objective: We compared total free-living activity energy expenditure (AEE) and physical activity level in women successful and unsuccessful at maintaining a normal body weight. Design: Premenopausal, generally sedentary women were studied at their normal weight and 1 y later after no intervention. Two groups were identified on the basis of extreme weight changes: maintainers (n = 27) had a weight gain of ≤ 3% of their initial body weight ( ≤ 2 kg/y) and gainers (n = 20) had a weight gain of > 10% (> 6 kg/y). At baseline and follow-up, evaluations were conducted during 4 wk of diet-controlled, energy-balance conditions. Free-living AEE and physical activity were assessed with the use of doubly labeled water, exercise energy economy and muscle strength with the use of standardized exercise tests, and sleeping EE and substrate utilization with the use of chamber calorimetry. Results: Maintainers lost a mean (±SD) of 0.5 ± 2.2 kg/y and gainers gained 9.5 ± 2.1 kg/y. Gainers had a lower AEE (P < 0.02), a lower physical activity level (P < 0.01), and less muscle strength (P < 0.001); these differences between groups remained significant from baseline to follow-up. Sleeping EE, exercise economy, and sleeping or 24-h substrate utilization were not significantly different between the 2 groups. A lower AEE in the gainers explained ≈ 77% of their greater weight gain after 1 y. Conclusion: The general US population should increase their daily physical activity levels to decrease the rising prevalence of obesity. [ABSTRACT FROM AUTHOR]

Background: Intraabdominal adipose tissue (IAAT) is the body fat depot most strongly related to disease risk. Weight reduction is advocated for overweight people to reduce total body fat and IAAT, although little is known about the effect of weight loss on abdominal fat distribution in different races. Objective:We compared the effects of diet-induced weight loss on changes in abdominal fat distribution in white and black women. Design:We studied 23 white and 23 black women, similar in age and body composition, in the overweight state [mean body mass index (BMI; in kg/m2): 28.8] and the normal-weight state (mean BMI: 24.0) and 38 never-overweight control women (mean BMI: 23.4). We measured total body fat by using a 4-compartment model, trunk fat by using dual-energy X-ray absorptiometry, and cross-sectional areas of IAAT (at the fourth and fifth lumbar vertebrae) and subcutaneous abdominal adipose tissue (SAAT) by using computed tomography. Results: Weight loss was similar in white and black women (13.1 and 12.6 kg, respectively), as were losses of total fat, trunk fat, and waist circumference. However, white women lost more IAAT (P < 0.001) and less SAAT (P < 0.03) than did black women. Fat patterns regressed toward those of their respective control groups. Changes in waist circumference correlated with changes in IAAT in white women (r = 0.54, P < 0.05) but not in black women (r = 0.19, NS). Conclusions: Despite comparable decreases in total and trunk fat, white women lost more IAAT and less SAAT than did black women. Waist circumference was not a suitable surrogate marker for tracking changes in the visceral fat compartment in black women. [ABSTRACT FROM AUTHOR]

Background: Lean mass and resting energy expenditure (REE) decrease with age. However, it is unknown whether age-related changes in regional lean and fat mass are responsible for the age-related decrease in REE. Objective: Our objective was to determine how regional lean and fat mass vary with age and whether age is independently related to REE after adjustment for regional fat and lean mass. Design: The study was a cross-sectional evaluation of 58 white women aged 23-77 y. Regional and whole-body lean and fat mass were measured by dual-energy X-ray absorptiometry, subcutaneous abdominal tissue (SAT) and intraabdominal adipose tissue (IAF) by computed tomography, and REE by ventilated-canopy indirect calorimetry. Results: Independent of other significant correlates, age was significantly and independently associated with greater IAF (β = 0.49) and less leg lean mass (β = -0.35). IAF (r = -0.28) and IAF:SAT (r = -0.31) correlated negatively with REE. REE was negatively associated with greater age (β = -0.42), independent of changes in lean and fat mass in different parts of the body. By contrast, trunk lean (β = 0.27) and leg fat (β = 0.27) mass were associated with greater REE independent of age and other body-composition variables. Conclusions: These results suggest that trunk lean mass (presumably primarily organ tissue) is relatively resistant to age-related changes in body composition, whereas muscle mass, especially leg muscle, tends to be lost. These data also suggest that the age-related decreases in REE are not fully explained by changes in body composition. [ABSTRACT FROM AUTHOR]

Background: Obese persons generally regain lost weight, suggesting that adaptive metabolic changes favor return to a preset weight. Objective: Our objective was to determine whether adaptive changes in resting metabolic rate (RMR) and thyroid hormones occur in weight-reduced persons, predisposing them to long-term weight gain. Design: Twenty-four overweight, postmenopausal women were studied at a clinical research center in four 10-d study phases: the overweight state (phase 1, energy balance; phase 2, 3350 kJ/d) and after reduction to a normal-weight state (phase 3, 3350 kJ/d; phase 4, energy balance). Weight-reduced women were matched with 24 never-overweight control subjects. After each study phase, assessments included RMR (by indirect calorimetry), body composition (by hydrostatic weighing), serum triiodothyronine (T3), and reverse T3 (rT3). Body weight was measured 4 y later, without intervention. Results: Body composition-adjusted RMR and T3:rT3 fell during acute (phase 2) and chronic (phase 3) energy restriction (P < 0.01), but returned to baseline in the normal-weight, energy-balanced state (phase 4; mean weight loss: 12.9 ± 2.0 kg). RMR among weight-reduced women (4771 ± 414 kJ/d) was not significantly different from that in control subjects (4955 ± 414 kJ/d; P = 0.14), and lower RMR did not predict greater 4-y weight regain (r = 0.27, NS). Conclusions: Energy restriction produces a transient hypothyroid-hypometabolic state that normalizes on return to energy-balanced conditions. Failure to establish energy balance after weight loss gives the misleading impression that weight-reduced persons are energy conservative and predisposed to weight regain. Our findings do not provide evidence in support of adaptive metabolic changes as an explanation for the tendency of weight-reduced persons to regain weight. [ABSTRACT FROM AUTHOR]

Examines whether scientific evidence supports the recommendation that dairy foods be consumed daily for improved bone health in the general population in the United States. Variation of dairy foods in their content of nutrients known to affect calcium excretion and skeletal mass; Select age, sex or ethnic groups that are more or less likely to benefit from regular use of dairy foods.

Compares the free-living energy expenditure and physical activity of black and white women before and after weight loss. Proportion of the decrease in sleeping and resting energy expenditures; Improvement of the physiologic capacity for exercise; Similarity of the free-living physical activities of the two groups of women.

Compares aerobic fitness and energy expenditure of premenopausal African American and White women in the United States. Variation of limb and trunk lean tissues in African American and White women; Differences in the energy expenditure and maximal oxygen uptake; Influence of visceral organ mass on energy expenditure differences.

Presents the Nutritional Dairy Council Award for Excellence in Medical/Dental Nutrition Education lecture at the 1995 American Society for Clinical Nutrition (ASCN) annual meeting, which focuses on the factors important for developing a successful medical-nutrition education program. Goals of a medical-nutrition education program; Critical factors; Other important factors.

We examined the pattern of weight maintenance in 24 obese women [body mass index (BMI; in kg/m²) 27.6 ± 0.4 who were provided foods for a balanced deficit diet until each had lost ≥ 10 kg and attained normal body weight (BMI 22.9 ± 0.4). At 1 y subjects had regained a mean of 42% of their weight loss, which increased to 87% at 4 y. At 4 y 44% of patients had regained < 75%, whereas 37% had regained ≥ 100% of the weight originally lost. The amount of weight gained was markedly different from that observed in 24 pair-matched never-obese control subjects over the same length of follow-up. Because the results reported herein were obtained without teaching the subjects weight-control skills, they may be regarded as reflective of the natural history of weight maintenance in this population and may serve as a reference for various weight-intervention programs. The pattern of weight rebound observed in this study is very similar to the pattern observed in combined results from published diet and behavioral-modification programs, which raises important questions regarding the efficacy of these approaches in long-term weight maintenance. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the effects of a nutrition-education program provided by a physician nutrition specialist in a family-practice residency program on residents' and faculty members' nutrition knowledge and nutrition-related patient care, their patients' perceptions of the importance of nutrition, and the physicians' dietary patterns. The nutrition specialist provided recommendations for nutrition patient-care practices to the physicians for 6 mo. Pre- and post- intervention assessments included 1) nutrition exams for physicians and patients, 2) patient questionnaires concerning attitudes towards nutrition, 3) chart reviews, and 4) diet records for physicians. The educational intervention caused a small but statistically significant (P < 0.01) increase in physicians' nutrition-knowledge scores and a significantly higher (P < 0.05) frequency of physicians discussing nutrition and recommending diets for their patients. Effects were greater among residents than among faculty members. The results suggest that a physician nutrition specialist can provide effective nutrition education within a residency program. [ABSTRACT FROM AUTHOR]

On the basis of literature values, the relationship between fat-free mass (FFM), fat mass (FM), and resting energy expenditure [REE (kJ/24 h)} was determined for 213 adults (86 males, 127 females). The objectives were to develop a mathematical model to predict REE based on body composition and to evaluate the contribution of FFM and FM to REE. The following regression equations were derived: 1) REE = 1265 + (93.3 X FFM)(r² = 0.727, P < 0.001); 2) REE = 1114 + (90.4 X FFM) + (13.2 X FM) (R² = 0.743, P < 0.001); and 3) REE = (108 X FFM) + (16.9 X FM) (R² = 0.986, P < 0.001). FM explained only a small part of the variation remaining after FFM was accounted for. The models that include both FFM and FM are useful in examination of the changes in REE that occur with a change in both the FFM and FM. To account for more of the variability in REE, FFM will have to be divided into organ mass and skeletal muscle mass in future analyses. [ABSTRACT FROM AUTHOR]

The separate effects of energy restriction and weight loss on serum lipids were studied in 24 postmenopausal moderately obese women before and after weight loss of > 10 kg to normal weight. Fasting serum triglycerides (TGs), total cholesterol (TC), high-density-lipoprotein (HDL) and low-density-lipoprotein (LDL) cholesterol, and insulin were measured at the end of four 10-d in-hospital phases, two before and two after weight loss: phase I, stable weight; phase II, 3350 kJ/d (800 kcal/d), followed by outpatient weight loss; phase III, 3350 kJ/ d (800 kcal/d); and phase IV, stable weight. Diet composition and exercise were constant the entire study. Energy-restriction effect was determined by comparing average values in stable-weight phases (I and IV) with low-energy phases (II and III); weight-loss effect was determined by comparing values in obese phases (I and II) with reduced-weight phases (III and IV). Energy restriction lowered TG, TC, LDL cholesterol, the LDL-HDL cholesterol ratio, and insulin and raised HDL cholesterol (all P < 0.05). Weight loss lowered TG, TC, LDL cholesterol, and insulin (all P < 0.01) but did not change HDL cholesterol or the LDL-HDL cholesterol ratio. The results suggest that reduction to a weight-steady nonobese state significantly lowers TG, TC. and LDL cholesterol but does not improve HDL cholesterol or the LDL-HDL cholesterol ratio. [ABSTRACT FROM AUTHOR]

It is not known whether the decrease in the thermic effect of food (TEF) in obesity is a consequence of obesity or a factor contributing to the development of obesity. The resting energy expenditure (REE) of 24 obese, nondiabetic, postmenopausal women was 5481 ± 110 kJ/24 h (1310 ± 26.4 kcal/24 h). After weight loss (12.7 ± 0.45 kg) the REE was significantly decreased (4858 ± 94 kJ/24 h, or 1161 ± 22.4 kcal/24 h) and equivalent to the REE of 4866 ± 119 kJ/24 h (1163 ± 28.5 kcal/ 24 h) in 24 never-obese, postmenopausal women. The TEF, expressed as a percentage of the calories ingested, was 8.2 ± 0.50% for obese subjects, 8.7 ± 0.57% for postobese subjects, and 9.8 ± 0.54% for never-obese subjects. Compared with never-obese subjects, the TEF was significantly reduced in obese subjects (P = 0.043) and remained unchanged after weight loss (P = 0.341). These findings indicate that the lower TEF in the obese subjects is uncorrected by weight loss, and thus it is a contributor to obesity rather than a consequence of obesity. [ABSTRACT FROM AUTHOR]

The ratio of resting metabolic rate (RMR) to fat-free mass (FFM) is often used to compare individuals of different body sizes. Because RMR has not been well described over the full range of FFM, a literature review was conducted among groups with a wide range of FFM. It included 31 data sets comprising a total of 1111 subjects: 118 infants and pre-schoolers, 323 adolescents, and 670 adults; FFM ranged from 2.8 to 106 kg. The relationship of RMR to FFM was found to be nonlinear and average slopes of the regression equations of the three groups differed significantly (P < 0.0001). For only the youngest group did the intercept approach zero. The lower slopes of RMR on FFM, at higher measures of FFM, corresponded to relatively greater proportions of less metabolically active muscle mass and to lesser proportions of more metabolically active nonmuscle organ mass. Because the contribution of FFM to RMR is not constant, an arithmetic error is introduced when the ratio of RMR to FFM is used. Hence, alternative methods should be used to compare individuals with markedly different FFM. [ABSTRACT FROM AUTHOR]

Two studies were performed to investigate the association between body fat mass and fat oxidation. The first, a cross-sectional study of 106 obese women maintaining stable body weight, showed that these two variables were significantly correlated (r = 0.56, P < 0.001) and the regression coefficient indicated that a 10-kg change in fat mass corresponded to a change in fat oxidation of ~20 g/d. The second, a prospective study, validated this estimate and quantifies the long-term adaptations in fat oxidation resulting from body fat loss. Twenty-four moderately obese women were studied under controlled dietary conditions at stable weight before and after mean weight and fat losses of 12.7 and 9.8 kg, respectively. The reduction in fat oxidation was identical to that predicted by the above regression. We conclude that changes in fat mass significantly affect fat oxidation and that this process may contribute to the long-term regulation of fat and energy balance in obese individuals. [ABSTRACT FROM AUTHOR]

The Southeastern Regional Medical-Nutrition Education Network (SERMEN) was developed to coordinate and improve nutrition education in a consortium of the medical schools in Alabama, Florith, Georgia, and South Carolina. SERMEN's central office is at the Medical Cbllege of Georgia with the testing office at the University of Alabama at Birmingham. Students, faculty, and consultants in nutrition, education, and computer networking work together on projects on each campus that are coordinated and planned through semiannual meetings. A standardized examination was developed with the Nutrition Test-Item Bank to assess nutrition knowledge at various years of medical students from network schools. Each SERMEN school is connected to a microcomputer system at the central office that provides access to a data base of nutrition education and resources on each campus for developing curricula and syllabi. Funding has been provided by societies, foundations, and government agencies. [ABSTRACT FROM AUTHOR]

Fundamental aspects of the body impedance analysis (BIA) method were investigated to determine limitations. This method measures body impedance with a low-level (800 µA) 50-KHz current conducted through the tissues. A linear regression equation was proposed to relate impedance measurements to total body fat. The hydrostatic densitometry method (underwater weighing) was used to validate the proposed mathematical expression. A correlation coefficient of 0.98 between these two methods was obtained. The overall results from this study indicate the usefulness of the BIA method in determining percent body fat in humans provided body fluids are not perturbed several hours before the measurements. [ABSTRACT FROM AUTHOR]

The Southeastern Regional Medical-Nutrition Education Network (SERMEN) comprises 11 medical schools with varied nutrition training programs. A faculty representative from each school rated 41 topics in nutrition as to their importance for medical practice. From the seven topics unanimously chosen, a 90-item examination was prepared using the University of Alabama School of Medicine's Nutrition Test-Item Bank. Thirteen additional items surveyed student attitudes toward their nutrition training. Twenty-one percent of senior students from 10 SERMEN schools took the examination. Results showed significant variation in knowledge levels among the schools on the overall examination and on the seven topics. Eighty-five percent were dissatisfied with the quantity and 60% with the quality of their medical-nutrition education. Knowledge scores correlated with the students' assessments with r values of 0.28 and 0.35, respectively(p <0.001). Findings indicate significant variation in nutrition knowledge of US medical students. [ABSTRACT FROM AUTHOR]

Dietary calcium, magnesium, and polyunsaturated and saturated fat have each been implicated as being important factors in the development and treatment of hypertension. Although the mechanisms underlying the relationship between calcium and blood pressure are not clearly defined, calcium supplementation may be effective in lowering blood pressure in certain calcium sensitive subgroups. Dietary polyunsaturated fat intake as a source of linoleic acid may be important in the production of prostaglandins, which are known to modify blood pressure levels. Available evidence indicates that an increased intake of polyunsaturated fat relative to saturated fat may have a hypotensive effect in individuals with borderline hypertension. The mechanisms by which magnesium modifies blood pressure are thought to be both direct and indirect, probably interacting with other electrolytes known to affect vascular smooth muscle tone such as sodium, potassium, and calcium. There is insufficient information from human studies to conclude that magnesium supplementation will lower blood pressure levels. [ABSTRACT FROM AUTHOR]

A response from the author of the article "Iodine and selenium deficiency associated with cretinism in northern Zaire" in a 1990 issue is presented.

A letter to the editor is presented in response to the subject of the link between consumption of dairy and bone health.

Editorial. Examines the challenges which face the modern discipline of clinical nutrition, in relation to malnutrition from disease. Reference to a study conducted; How the study was conducted; What the study revealed.

Weight reduction is associated with a decrease in the risk of developing cardiovascular disease. We hypothesized that, given the central role of reactive oxygen and nitrogen species in vascular biology, changes in nitric oxide (NO) metabolism contribute to benefits of weight loss. In a controlled weight loss trial involving overweight (body mass index (BMI) = 27–30 kg/m2), otherwise healthy premenopausal Caucasian and African-American women, serum levels of nitrite and nitrate, as an index of NO production, and protein 3-nitrotyrosine and myeloperoxidase (MPO), as markers of inflammation, were determined. Testing was performed before and after reduction to normal body weight (BMI < 25) under standardized conditions, with controlled diet, and following 1 month of weight maintenance. After weight loss there was an increase in nitrite and nitrate, and levels were higher among African-American women relative to Caucasian counterparts. Whereas weight loss was associated with a decrease in 3-nitrotyrosine in Caucasian women, no change was observed among African-Americans. Furthermore, MPO levels increased in response to weight loss for African-Americans, but did not change in Caucasian women. These data indicate that vascular production of reactive nitrogen species can be modulated by race and weight loss and highlight important racial differences in these responses and are discussed in the context of risk for developing vascular disease. [Copyright &y& Elsevier]