Evaluation of weight loss protocols for dogs

Several canine weight loss protocols were evaluated to determine their relative safety and efficacy. Dogs were fed 100%, 75%, 60%, or 50% of maintenance energy requirements (MERs) using the dogs' target body weights. No indications of adverse health effects were observed with any weight loss protocol. Triiodothyronine (T3) levels and apparent MERs decreased in dogs restricted to 50% to 60% of their MERs. The rate of weight loss was correlated linearly with degree of calorie restriction, although there was considerable individual variation. Percent overweight by the end of the test was not different between protocol groups for dogs fed 50%, 60%, or 75% of MERs. Therefore, any of the protocols tested in this study may be used in the management of overweight dogs; however, individual responses will be expected to vary, and severe calorie restriction may predispose dogs to weight rebound.

Exercise in the treatment of obesity: effects of four interventions on body composition, resting energy expenditure, appetite, and mood

This study investigated changes in body composition, resting energy expenditure (REE), appetite, and mood in 128 obese women who were randomly assigned to 1 of 4 treatment conditions: diet alone, diet plus aerobic training, diet plus strength training, or diet combined with aerobic and strength training (i.e., combined training). All women received the same 48-week group behavioral program and were prescribed the same diet. Exercising participants were provided 3 supervised exercise sessions per week for the first 28 weeks and 2 sessions weekly thereafter. Participants across the 4 conditions achieved a mean weight loss of 16.5 +/- 6.8 kg at Week 24, which decreased to 15.1 +/- 8.4 kg at Week 48. There were no significant differences among conditions at any time in changes in weight or body composition. Women who received aerobic training displayed significantly smaller reductions in REE at Week 24 than did those who received strength training. There were no other significant differences among conditions at any time on this variable or in changes in appetite and mood.

Psychological consequences of food restriction

A review of the literature and research on food restriction indicates that inhibiting food intake has consequences that may not have been anticipated by those attempting such restriction. Starvation and self-imposed dieting appear to result in eating binges once food is available and in psychological manifestations such as preoccupation with food and eating, increased emotional responsiveness and dysphoria, and distractibility. Caution is thus advisable in counseling clients to restrict their eating and diet to lose weight, as the negative sequelae may outweigh the benefits of restraining one's eating. Instead, healthful, balanced eating without specific food restrictions should be recommended as a long-term strategy to avoid the perils of restrictive dieting.

Sensitivity associated with the identification of visceral adipose tissue levels using waist circumference in men and women: effects of weight loss

OBJECTIVE

The first objective was to determine the associated sensitivity (true positives) and specificity (false positives) associated with the use of waist circumference (WC) to predict specific visceral adipose tissue (VAT) levels. Because WC is a strong correlate of VAT, and, a WC of 100 cm and a VAT area of 130 cm2 (L4-L5) have been suggested as thresholds for increased disturbances in insulin-glucose homeostasis and lipid metabolism, we assessed the sensitivity and specificity when using a WC of 100 cm to identify a VAT of 130 cm2 or greater. A second objective was to evaluate the effects of diet and exercise induced weight loss on VAT and WC to establish the utility of using WC to follow reductions in VAT.

RESEARCH DESIGN AND METHODS

The sensitivity between WC and VAT was assessed using 50 male (BMI: 30.9 +/- 4.7, age: 41.0 +/- 11.2 y) and 49 female (BMI: 33.3 +/- 5.0, age: 36.9 +/- 7.4 y) subjects. The effects of weight loss on WC and VAT were evaluated in a subgroup of 20 male and 38 female subjects. VAT was measured by magnetic resonance imaging.

RESULTS

The sensitivity associated with the prediction of a VAT of 130 cm2 or greater using a WC of 100 cm was high (83%), however, so too was the incidence of false positives (38%). Significant (p < 0.01) correlations were obtained between concurrent reductions in VAT and WC for both the male (r = 0.69) and female (r = 0.47) groups. For the two groups combined, regression analysis indicated that a 1 cm reduction in WC was associated with a 4% reduction in VAT mass (p < 0.01).

CONCLUSIONS

The misclassification of individuals with VAT accumulation above 130 cm2 suggest that WC alone lacks the sensitivity required to identify specific VAT values. The diet and exercise induced reductions in visceral adiposity are positively related to corresponding reductions in WC for both genders is a positive result, and demonstrates the potential utility of using WC to follow changes in the AT depot that conveys the greatest health risk.

Bone loss accompanying diet-induced or exercise-induced weight loss: a randomised controlled study

OBJECTIVE

To compare the effects of two weight loss interventions, diet or exercise, on changes in bone, fat and lean tissue.

DESIGN

Prospective, long term, worksite, randomised and controlled weight-loss study using a low fat diet ad libitum or moderate aerobic exercise.

SUBJECTS

66 overweight men (mean age 43.4 +/- 5.7 y, BMI 29.0 +/- 2.6 kg/m2).

MEASUREMENTS

Body weight, lean mass, fat mass, bone mass (BMC), bone mineral density (BMD) by dual-energy X-ray absorptiometry.

RESULTS

Dieters lost 1.4% BMC (1.5% BMD) with 6.4 kg weight loss; there was no significant change in BMC (or in BMD) in exercisers (2.6 kg weight loss) or in control subjects (no weight change). Changes in BMC were correlated with fat loss with both interventions: 11.7 g BMC/kg fat loss in dieters, 11.4 g BMC change/kg fat loss in exercisers.

CONCLUSION

BMC loss with diet-induced weight loss reflects loss of weight and especially loss of body fat. Further study to determine whether similar BMC loss will accompany equivalent weight loss induced by exercise is needed.

Changes in the body composition of cats during weight reduction by controlled dietary energy restriction

Thirteen overweight domestic short-haired cats were fed a commercial low calorie diet for 18 weeks at an energy intake to lose weight; they lost an average of 18.1 per cent of their starting weight. An evaluation of their body composition by dual energy x-ray absorptiometry before and after the study suggested that most of the weight lost was composed of fat. The cats' lean bodyweight did not change significantly, but increased as a proportion of total bodyweight.

Contribution of dieting to the inverse association between energy intake and body mass index

OBJECTIVE

To examine the association of energy and % energy from fat with body mass index (BMI) and determine if self-reported dieting altered observed associations.

DESIGN

Dietary intake data based on dietary recalls from four nonconsecutive days over a 1 year period were examined relative to BMI. The relation between energy intake and % energy from fat and BMI was examined by linear regression analysis.

SUBJECTS

The sample included 1854 free-living women aged 19-50 years who participated in the 1985-6 Continuing Surveys of Food Intakes by Individuals conducted by the United States Department of Agriculture.

RESULTS

Reported energy intake was inversely associated with BMI (regression coefficient (beta) = -0.001 24, standard error (s.e.) = 0.000 31). Controlling for low energy dieting alone reduced the inverse energy intake-BMI association by approximately 20% (beta = -0.001 00, s.e. = 0.000 31), compared to reductions of 16%, 13% and 10%, respectively, when health status, age and education were added individually to the energy intake-BMI linear regression. Physical activity, smoking status, % energy from fat and report of low fat dieting did not reduce the energy intake-BMI association. Controlling for nondietary factors related to BMI and potentially influencing energy intake reduced the inverse energy intake-BMI association by approximately 22% (beta = -0.000 97, s.e. = 0.00025). Further adjustment for low energy dieting on day 1 reduced the inverse energy intake-BMI association by 40% (beta = -0.000 74, s.e. = 0.000 26), suggesting that intermittent energy restriction was a significant factor in the reduced energy intake reported among overweight women. Percent energy from fat was not associated with BMI (beta = 0.049, s.e. = 0.025, P = 0.055). Exclusion of 37 women reporting poor health status further attenuated the inverse association between energy intake and BMI (beta = -0.000 64), s.e. = 0.000 26), while it strengthened the previously non-significant positive association between % energy from fat and BMI (beta = 0.062; s.e. = 0.024).

CONCLUSION

Intermittent energy restriction appeared to be a significant factor in the reduced energy intake reported among overweight women in this sample. Adequate assessment of energy expenditure is required to correctly interpret the association of energy intake to body weight.

Electrocardiographic findings associated with very low calorie dieting

OBJECTIVE

To determine the safety of very low calorie diets (VLCD) in regard to their effects on cardiac function.

DESIGN

EKG changes were analyzed for 126 women on a VLCD of 3349 kJ/d (800 kcal/d). EKGs were done when the diet was begun, after 3 months of dieting, and at a 6 month follow up after being off the diet for 3 months.

SETTING

Subjects were solicited through advertisements and charged $1,000 for participating after being screened for age, weight, and health status.

MAIN OUTCOME MEASURES

EKG QTc intervals, PR interval, QRS interval, ST-T wave changes, and heart rate.

RESULTS

Over one-fourth (27.0%) of subjects had normal EKGs at all three time points studied. Sinus bradycardia was the most common abnormality, observed in 60 subjects (47.6%) on at least one of the three EKGs. Fifty-eight (46%) patients had EKGs with ST-T wave abnormalities observed on at least one of the EKGs. Eight subjects (6.4%) had prolonged QTc (more than one standard deviation beyond the average for women) intervals on at least one EKG. None of these eight persons had significant untoward medical consequences.

CONCLUSION

A VLCD diet of 3349 kJ/d (800 kcal/d) for up to 3 months is not associated with significant electrocardiographic abnormalities or clinical cardiac complications, provided the patients have low cardiovascular risk at baseline.

Cognitive effects of ketogenic weight-reducing diets

OBJECTIVE

To determine whether ketogenic weight reducing diets have adverse effects on cognitive performance.

SUBJECTS

21 overweight women (mean BMI = 41 kg/m2).

DESIGN

Randomized double-blinded study.

METHOD

Subjects were randomized to ketogenic or nonketogenic liquid formula very low energy diets, that were comparable in energy and in protein content. Subjects remained on the diet for 28 days and were reevaluated periodically with brief measures of cognitive performance assessing attention and mental flexibility.

RESULTS

Weight losses were comparable on the two diets (Mean = 8.1 kg). Performance on attention tasks did not differ as a function of the diet. However, performance on the trail making task, a neuropsychological test that requires higher order mental processing and flexibility, was adversely affected by the ketogenic diet. The worsening in performance was observed primarily between baseline and week one of the ketogenic diet.

CONCLUSIONS

Further research is needed to confirm this finding and to determine whether ketogenic diets negatively affect other complex mental tasks, such as problem solving.

Exercise in the treatment of childhood obesity

Research on exercise in the treatment of childhood obesity is reviewed. The role of activity or sedentary behaviors in the development of obesity is discussed, with a conceptual model for understanding choice of being sedentary or active presented. Research that assesses the effects of exercise alone and diet plus exercise on child weight control are reviewed, as well as new research on modifying access to sedentary behaviors. Treatment research suggests exercise alone is not sufficient, with the combination of diet plus exercise more effective for long-term than short-term changes. Finally, suggestions for new research are presented.

Weight concerns and eating patterns: a survey of university students in Europe

OBJECTIVE

To assess a wide range of health-related behaviours, beliefs and knowledge in educated young adults.

DESIGN

A standardized questionnaire was developed, translated, and administered in university classes.

SUBJECTS

16,486 university students in 21 European countries.

DEPENDENT VARIABLES

Reported and self-perceived body size, eating practices and weight concerns.

RESULTS

Body Mass Index (BMI; weight (kg)/height (m)2) was slightly different between countries, and rather low overall (20.5 in women and 22.0 in men). These low values can be attributed to the young age of respondents (21.4 years) and to their presumably high socio-economic status. Very few were overweight (8%) and less than 1% were obese. In spite of the low BMI, many perceived themselves as overweight, especially among women. Trying to lose weight (44% of women, 17% of men) and dieting (14% in women and 3% in men) were not uncommon, although large differences existed between countries. Dieting affected snack and meal patterns: dieters reported fewer snacks and female dieters also reported fewer meals than non-dieters. Breakfast was skipped by almost twice as many dieters as non-dieters. Some evidence of anorexia nervosa (dieting in very underweight individuals) appeared.

CONCLUSION

The data suggest excessive responses to weight loss pressures and imperfect translation of nutritional advice into behaviours.

A very-low-calorie conventional Japanese diet: its implications for prevention of obesity

A very-low-calorie conventional Japanese diet of 370 kcal/day has been shown to be useful for weight reduction and its long-term maintenance. Sources of the diet were mainly from chicken fillet, egg white, fish white-meat, mushroom, seaweed and low- or non-calorie fiber-rich vegetable, and contained 4.4g fat, 38.1g protein, 45.2g carbohydrate and essential minerals and vitamins. However, metabolic and neural implications of a commercial very-low-calorie liquid formula diet have rarely been investigated from the view point of food intake and appetite regulation. Animal studies have demonstrated the rationale for efficacy of the very-low calorie conventional Japanese diet as follows: (1) Increased hypothalamic histamine suppressed food intake through H1-receptors in the ventromedial hypothalamus (VMH) and paraventricular nucleus, the satiety centers. (2) Low energy intake enhanced satiety and decreased food intake through histaminergic activation of VMH neurons. (3) Mastication activated afferent signal transmission from proprioceptors in the oral cavity to the mesencephalic trigeminal nucleus(Me5). Histaminergic systems in the hypothalamus were activated by mastication and low energy supply, which was accompanied by satiation through the action of histamine in the VMH. Usefulness of the very-low-calorie conventional Japanese diet derives from utilization of conventional Japanese food stuffs as a fiber rich, low energy food source, and from enhancement of satiation by increased mastication required of the diet. The properties of the diet seemed to effect a closed positive feedback loop between histaminergic activation in hypothalamic satiety centers and behavioral changes to enhance satiation and cause feeding suppression.

Antiaging action of caloric restriction: endocrine and metabolic aspects

Restricting the energy intake of mice and rats slows the rate of actuarial aging, delays or prevents most age-associated disease processes, and maintains physiological processes in a youthful state at advanced ages. This manipulation is effective when initiated in young animals or in adult life. Although body fat is decreased by this reduction in energy intake, the reduction in body fat is not causally related to the antiaging action. Nor does this reduction in energy intake slow the aging processes by decreasing the metabolic rate, but it may do so by altering the characteristics of fuel use. Another possible mechanism underlying the antiaging action is the general protection restriction of energy intake provides against harmful agents, an action which may be the result of an alteration in adrenal glucocorticoid physiology.

A public health approach to the problem of obesity

Overweight and obesity have an underestimated impact on public health and therefore on national economic costs. The rising prevalence of overweight and obesity is inextricably linked to the increase in the average BMI and its population distribution. English activity patterns have probably fallen over 20 years by an average of 800 kcal/day; the remarkable changes in eating patterns reflect the pervasive physiological suppression of intake by about 750 kcal/d. The resulting small positive energy balance explains the secular increase in average adult weight. Similar changes and discrepancies occur with aging. Together these changes can explain the accelerating skewness of BMI distribution and particular propensity of women to obesity. The genetically susceptible probably dominate the upper BMI range and seem to reflect subtle discrepancies in energy balance in an inactive society on a high fat diet. Maternal programming of gene expression in utero may amplify intergenerational increases in weight but also amplify a stress-mediated susceptibility to abdominal obesity. The needed transformation in thinking on transport, environment, work facilities, education, health and food policies and perhaps in social and economic policies is unlikely when governments are wedded to individualism but without these changes to enhance physical activity and alter food quality societies are doomed to escalating obesity rates.

Relationship of co-morbidities of obesity to weight loss and four-year weight maintenance/rebound

This study examined the effect of weight loss (separate from energy restriction) and weight maintenance/rebound over time on blood pressure, serum lipids, and body composition in 24 obese (mean 137% ideal body weight (IBW)) females with mild to moderate hypertension. Weight loss was induced under tightly controlled General Clinical Research Center conditions until each subject had lost at least 10 kg (mean 13 kg) and attained normal body weight (< 120% IBW). After 4 years subjects returned for repeat evaluation. Weight changes were compared with 24 pair-matched normal weight controls who were also followed for 4 years. With weight loss, significant improvements were seen in standing mean arterial pressure (MAP), serum total cholesterol, low-density lipoprotein cholesterol, and triglycerides. Subjects regained 11 kg (87% of the weight lost) over the 4 year follow-up period while control subjects gained only 2 kg. Subjects who chose self-selected exercise gained less weight than nonexercisers (6 kg vs. 13 kg, P < 0.05). With weight regain there were significant increases in standing and supine MAP, total cholesterol, and high-density lipoprotein (HDL) cholesterol. The amount of weight regained was significantly correlated with standing MAP (r = 0.73), triglycerides (r = 0.43), and HDL cholesterol (r = -0.47). The percentage fat of the weight regained was no greater than that of the weight previously lost. Weight loss, distinct from energy restriction, was associated with improvements in blood pressure and serum lipid levels. The ability to sustain these improvements in the co-morbidities of obesity was directly related to the persistence and magnitude of weight loss maintenance.

Treatment of obesity by personality classification-oriented program

It is apparent that personality is related to the pathogenesis of obesity, and that understanding the personality of the patient may be a key to successful treatment of the disease. Using the Rorschach test and interviews by a psychiatrist, the types of personality were classified into four groups according to the healthiness of personalities. The judgment of healthiness was based mainly on the scores obtained from the Rorschach test. This classification revealed that the occurrence of mental and physical symptoms during therapy with a very low calorie diet (VLCD) and subsequent rebound of bodyweight were more frequently observed in patients with relatively less healthy personalities. We used this classification to adapt our program to treat obese patients. In this program, severe diet restrictions were applied to patients with relatively healthy personalities. These restrictions were applied with modifications to patients with less healthy personality, because severe restrictions would be possibly very stressful for them and would bring about an undesirable reaction. For strengthening the patients' motivation for therapy, the significance of body weight reduction was explained in different ways to patients with different types of personality. The target of bodyweight reduction, reward for patients with successful weight reduction, and the duration of therapy were set up differently for patients with different personalities types. The results showed that bodyweight rebound one or two years after treatment was reduced with the personality-oriented therapy program compared to that observed with the previous conventional therapies. Also, the incidence of psychological problems was remarkably decreased.

Prevention of obesity in middle-aged monkeys: food intake during body weight clamp

Prevention of obesity and increase in longevity in obesity-prone rodents can be achieved by long-term moderate dietary restriction. In order to examine the likelihood that caloric restriction could have similar salutary effects in humans, rhesus monkeys, after reaching mature adult stature, were placed on a protocol to clamp or stabilize body weight by weekly caloric adjustment. Furtherweight gain was prevented by this caloric titration procedure, and thus middle-age onset obesity, which is very common in this species, was prevented. The present study analyzed daily food intake for six weight-clamped monkeys and six ad libitum fed age-matched animals over a 3-year period, ages 18.5 to 21.5 years. After approximately 9 years of caloric restriction the daily calorie load to maintain stable adult body weight proved to be 40% less than the amount ingested by ad libitum fed animals. Calories per kg body weight did not differ significantly between the groups although the ad libitum fed animals were significantly fatter than the weight-clamped group. Prevention of obesity using this weight clamp protocol has also maintained lower insulin levels and higher glucose tolerance in the restricted animals.

Hepatic mitochondrial respiration and transport of reducing equivalents in rats fed an energy dense diet

OBJECTIVE

To measure hepatic mitochondrial respiration as well as the ability of hepatic mitochondria to transport reducing equivalents by shuttle systems in rats fed an energy dense diet.

DESIGN

Rats were fed a control (CD) or energy dense (ED) diet for 15 days.

MEASUREMENTS

State 3 and State 4 oxygen consumption were measured in isolated mitochondria using glutamate+malate or pyruvate+malate as substrate. We also measured malate-aspartate shuttle activity and mitochondrial alpha-glycerophosphate dehydrogenase activity.

RESULTS

ED rats, in comparison with CD rats, showed a significantly greater energy intake without a corresponding greater body weight gain and carcass lipid content. Compared to CD rats, ED rats also showed a significant increase in resting metabolic rate, which was abolished by propranolol. Hepatic mitochondrial state 3 respiration using glutamate+malate or pyruvate+malate as substrate as well as malate-aspartate shuttle activity significantly decreased, while mitochondrial alpha-glycerophosphate dehydrogenase significantly increased in ED rats compared to CD rats.

CONCLUSIONS

Mitochondrial NADH oxidation is reduced and a greater fraction of cytoplasmic NADH can be transported to the mitochondria through the alpha-glycerophosphate shuttle and oxidized through the respiratory chain from complex II onwards. This mechanism could lead to a decrease in hepatic metabolic efficiency which is in line with the increased energy expenditure occurring in rats fed an energy dense diet.

Exercise enhances dietary compliance during moderate energy restriction in obese women

The effect of aerobic exercise on dietary compliance was assessed in 13 obese women (44 +/- 3% fat) during a 12-wk weight-reduction program (EX group). Seventeen obese women (45 +/- 5% fat) not engaged in aerobic exercise (NX group) served as control subjects. The reducing diets were designed to promote a weight loss of 1 kg/wk, with energy intakes individually prescribed (mean +/- SD: 4.9 +/- 0.6 MJ/d) to approximate 75% of each subject's measured basal metabolic rate. The EX group completed of three 45-min sessions/wk of supervised aerobic exercise at 65% of maximal oxygen consumption (VO2max). Daily energy intakes were calculated by summing changes in body stores, measured by total body water isotope dilution, and total daily energy expenditure, measured by doubly labeled water (DLW). Dietary compliance was assessed by comparing calculated intakes with prescribed intakes. Both the EX and NX groups reported consuming close to their prescribed daily intakes, with differences of -0.08 +/- 0.28 (EX group) and +0.03 +/- 0.57 (NX group) MJ/d, respectively. However, expenditure/balance data determined by the DLW method indicated that the EX subjects exhibited better dietary compliance than the NX subjects, with intakes exceeding those prescribed by only 0.7 +/- 1.5 compared with 2.3 +/- 1.6 MJ/d for the NX subjects (P = 0.01). Therefore, an additional benefit of aerobic exercise during energy restriction is enhanced dietary compliance, which has important implications for the treatment of moderate obesity.

The response to treatment of overweight in postmenopausal women is not related to fat distribution

OBJECTIVE

To investigate whether fat distribution or sex hormone status in overweight postmenopausal women do influence the response to treatment of overweight.

DESIGN

Longitudinal, clinical intervention study of a 4.2 MJ diet daily with or without exercise.

SUBJECTS

98 healthy, overweight, postmenopausal women (age: 49-58 y, BMI: 25-42 kg/m2).

MEASUREMENTS

Various fatness and fat distribution parameters (by dual-energy x-ray absorptiometry and anthropometry), sex hormone-binding globulin (SHBG), sex hormones, and the resting energy expenditure (REE) at baseline and after 3 months.

RESULTS

Reductions in weight and fat were independent of the initial fat distribution and the REE, but were significantly associated with high initial SHBG levels. Furthermore, loss of fat was significantly and independently associated with increases in SHBG and reductions in central fat distribution.

CONCLUSION

Postmenopausal women with an android and gynoid fat distribution respond with similar weight loss to treatment of overweight. Furthermore, a more healthy, less android, fat distribution and sex hormone status may be achieved with increasing weight loss.

Effect of weight loss and body position on pulmonary function and gas exchange abnormalities in morbid obesity

OBJECTIVE

To determine, whether behavioral management of obesity including very-low-calorie-diet would produce weight loss enough to improve pulmonary mechanics and gas exchange in morbid obesity.

DESIGN

Pulmonary function and arterial oxygenation were studied before and after weight loss in 11 patients attending a group therapy with the program of VLCD for 6 weeks and 16 weeks' behavioral intervention.

MEASUREMENTS

Spirometry, diffusing capacity, body plethysmograph, closing volume and arterial blood gas analyses.

RESULTS

The mean initial BMI was 45.4 kg/m2 (range 39.8-58.7 kg/m2) and decreased to 39.4 kg/m2 (range 31-49.8 kg/m2) (P < 0.01). Expiratory reserve volume (ERV) and functional residual capacity (FRC) improved significantly with weight loss. Closing capacity (CC) exceeded FRC in 10 cases of 11 at the initial stage, but after weight loss only in three patients. The mean arterial oxygen tension with the patients in supine position did not change after weight loss, but standing up improved PaO2 significantly before and after weight loss.

CONCLUSION

The dietary treatment of morbid obesity was sufficient to induce improvement in lung volumes, but not enough to improve arterial oxygenation, although ventilatory mechanics was improved significantly and the tendency to early small airway closure was decreased. Hypoxemia was significantly relieved by standing up both before and after weight loss.

Prognostic markers for diet-induced weight loss in obese women

OBJECTIVE

To identify prognostic metabolic and hormonal markers for long-term weight loss outcome in obese women.

DESIGN

Dietary intervention consisting of 36 weeks treatment by a 4.2 MJ/d low-fat high carbohydrate diet, and follow-up 2 1/2 years after termination of treatment.

SETTING

Outpatient clinic in Copenhagen.

SUBJECTS

Forty consecutive female obese patients aged 15 to 62 years.

MAIN OUTCOME MEASURE

Weight loss.

RESULTS

The maximum weight loss (mean 16.2 kg, 95% CI 14.2-18.2) was positively associated to pre-treatment 24-h energy expenditure (P < 0.01), fat oxidation (%) (P < 0.02), plasma dihydrotestosterone (DHT) (P < 0.01), and to postprandial noradrenaline concentration (P < 0.04). Together these factors could explain 41% of the variation in maximum weight loss. Only 24-h EE and DHT had predictive power on weight loss after 36 weeks. Weight losses in upper and lower tertiles of DHT concentrations were 17.7 kg (14.1-21.4) and 9.8 kg (6.2-13.3) (P < 0.02). The adjusted relative risk of losing < 10 kg in the upper compared to the lower DHT tertile was 12% (4-32%). At 2 1/2 y follow-up 21 patients had maintained some of the weight loss (54%), while 14 patients had maintained > 5 kg weight loss (36%). High levels of pre-treatment DHT were also associated with better weight loss at 2 1/2 y follow-up.

CONCLUSION

The study suggests that in particular DHT, but also 24-h EE, fat oxidation, and plasma noradrenaline, may be prognostic markers for weight loss outcome in obese women.

Orlistat (Ro 18-0647), a lipase inhibitor, in the treatment of human obesity: a multiple dose study

OBJECTIVE

To evaluate efficacy and tolerability of the lipase inhibitor Orlistat (Ro 18-0647) in doses of 10, 60 and 120 mg three times a day in addition to a mild hypocaloric diet containing 30% of calories as fat.

DESIGN

4 week single-blind placebo run-in period of diet alone followed by a 12 week double-blind, placebo-controlled, randomized treatment period.

SETTINGS

Five European outpatient clinics specializing in endocrinology and/or the treatment of obesity, one central laboratory.

SUBJECTS

Of 237 healthy obese subjects meeting the inclusion criteria, 188 showed compliance to the diet during the run-in period and were randomized for the treatment period.

MAIN OUTCOME MEASURES

Primary efficacy criterion was the difference in weight loss after 12 weeks of treatment between the Orlistat treated groups and the diet alone group. Secondary efficacy criteria were changes in serum total, HDL- and LDL-cholesterol.

RESULTS

Compared to placebo a mean (+/- s.e.) additional weight loss of 0.63 +/- 0.54 kg with 30 mg a day (P = 0.246), 0.71 +/- 0.55 kg with 180 mg a day (P = 0.190) and 1.75 +/- 0.54 kg with 360 mg a day was seen (P = 0.001) or Orlistat was observed. Overall data indicated dose-dependency. Small decreases were seen in total and LDL-cholesterol (significant in the 180 and 360 mg a day groups) and LDL- to HDL-cholesterol ratio (significant in the 360 mg a day group only). Mild, mostly gastrointestinal side effects were observed more frequently in the Orlistat groups and caused premature withdrawal from the study in only four patients. No marked laboratory abnormalities were shown, including the lipid-soluble vitamins A, D and E.

CONCLUSION

Orlistat, in an apparently dose-dependent manner, leads to additional weight loss compared to diet alone and overall, is well tolerated.

Compliance to dietary advice directed towards increasing the carbohydrate to fat ratio of the everyday diet

OBJECTIVE

To assess the effects, on food intake, body weight and body composition, of compliance to advice aiming at increasing the carbohydrate to fat ratio of the everyday diet without imposing voluntary restriction on the amount of food consumed.

DESIGN

Eight moderately overweight women (body mass index > 27 kg/m2, relative body fat mass > 30%) received dietary advice during a 2 month period. Additionally, each evening the subjects had to consume a meal artificially enriched with 13C-glucose in order to assess their compliance from the 13CO2 enrichment in expired air.

MEASUREMENTS

Dietary intakes, body weight, body composition and individual compliance.

RESULTS

The energy derived from fat decreased from 44 +/- 1% to 31 +/- 1% and the proportion of carbohydrate increased from 38 +/- 2% to 50 +/- 1%, whereas the absolute carbohydrate intake remained constant (182 +/- 18 g/d). Energy intake decreased by 1569 +/- 520 kJ/d. There was a net loss of fat mass (1.7 +/- 0.7 kg, P = 0.016) with fat free mass maintenance. Dietary compliance ranged from 20 to 93% (mean: 60 +/- 8%) and was positively correlated to the loss of body fat mass.

CONCLUSION

Advice aiming at increasing diet's carbohydrate to fat ratio induces a loss of fat mass with fat-free mass maintenance.

Clinical evaluation of a minimal intervention meal replacement regimen for weight reduction

OBJECTIVE

The purpose of this study was to evaluate a simplified weight loss program in which subjects were provided a widely available meal replacement product and its package insert information (Ultra Slim-Fast).

METHOD

Weekly follow-up visits were carried out by non-physician personnel for weight measurement, distribution of product, and completion of a subjective questionnaire. No dietary counseling was provided. A total of 273 of 301 subjects (91%) completed 12 weeks of study. Men lost 50% (from 119 to 108% of ideal body weight) and women lost 35% (from 122 to 111% of ideal body weight) of excess body weight. Thirty-five patients who lost < 9 lbs in 12 weeks were considered non-adherent and were excluded from the next phase of the study during which 238 subjects were followed biweekly.

RESULTS

Despite a $25/week payment for participation nearly 44% of subjects dropped out or were judged non-compliant prior to the end of the study. At 116 weeks, 133 (97 females, 36 males) of 238 subjects remained in the study (44% of the initial population), with average weight loss from baseline of 13.6 +/- 10.5 lb in females and 14.0 +/- 10.5 lb in males.

DISCUSSION

The weight loss observed (approximately 10% of body weight) is significant and has been associated with important health benefits particularly for patients with hypertension and non-insulin dependent diabetes. The potential advantages of using meal replacements for mild obesity include wide availability to aid compliance, low cost and minimal professional intervention.

Evaluating success of weight loss programs, with an application to fluoxetine weight reduction clinical trial data

We modified criteria for judging successful obesity treatment proposed by Atkinson to provide objective criteria for successful benefit from weight reduction programs with respect to data from a clinical trial. The criteria include assessments of changes in both weight-related factors (e.g. excess weight, excess body fat) and obesity-related risk factors (e.g. hypertension, hyperglycemia, hyperlipemia). To demonstrate the use of this methodology, we applied the criteria in an analysis of eight randomized, double-blind controlled trials comparing fluoxetine (n = 522) with placebo (n = 504) for weight loss. The results suggest these criteria can be useful for evaluating a treatment program or for comparing treatments from clinical trials.

Six months' follow-up on exercise added to a short-term diet in overweight postmenopausal women--effects on body composition, resting metabolic rate, cardiovascular risk factors and bone

The aim of this work was to study the long-term effects of the addition of exercise to a short-term diet in overweight postmenopausal women. A follow up study was made of 118 overweight, postmenopausal women, who 6 months earlier had completed 12 weeks of randomized intervention (three groups: 4.2 MJ/d diet, 4.2 MJ/d diet with exercise, and controls). The following were measured: body composition and fat distribution (measured by dual-energy X-ray absorptiometry), resting metabolic rate, serum lipids and lipoproteins, blood pressure, and bone mineral densities. It was found that weight was still significantly reduced (by about 8 kg). HDL-C was significantly increased (10%), and triglycerides decreased (20%), whereas the initial reductions in total cholesterol and LDL-C had disappeared at the follow-up. The women from the former diet-plus-exercise group, who were current exercisers at the follow-up, had a significantly greater reduction in weight (10.9 vs 6.6 kg), fat tissue mass (10.0 vs 5.4 kg) and abdominal-to-total-body fat tissue mass (9.6 vs 4.7), and a significantly greater increase in the resting metabolic rate (11.1 vs 1.1 kJ/kg/d), as compared with the non-exercisers from this group. There were no major detrimental changes in total body, spinal, or forearm bone mineral density or in markers of bone turnover. The short-term dietary treatment in this study may have beneficial long-term effects on weight, fat tissue mass and cardiovascular risk factors with no additional benefits from added exercise, unless the exercise is continued.

Weight loss beliefs, practices and support systems for high school wrestlers

PURPOSE

Wrestlers often engage in unhealthy practices to achieve a low body weight for competition. This study examined beliefs, practices, and potential support systems to promote safe weight loss among scholastic wrestlers.

METHODS

A written questionnaire was developed and administered to all nine high school wrestling teams in one rural county. Responses were obtained from 197 wrestlers.

RESULTS

Most wrestlers reported that "making weight" was very important. Increased activity and decreased food intake were the most frequent weight loss methods. Unsafe methods such as vomiting and use of laxatives were sometimes used, even though many wrestlers recognized these practices were unhealthy and decreased performance. Personal desire to win, coaches, and teammates were reported to be the greatest influences on weight loss efforts. Wrestlers believed that coaches and physicians were the most accurate sources of weight loss information.

CONCLUSION

Nutrition counseling which goes beyond simply providing information about the risk of rapid weight loss among adolescent wrestlers is needed. Emphasis on motivating wrestlers to adopt healthy weight management strategies is important. Wrestlers perceive physicians as credible sources of information, and physicians should become more actively involved in educating both coaches and athletes about safe weight management.

Very low-calorie diets. National Task Force on the Prevention and Treatment of Obesity, National Institutes of Health

OBJECTIVE

To provide an overview of the published scientific information on the safety and efficacy of very low-calorie diets (VLCDs) and to provide rational recommendations for their use.

DATA SOURCES AND EXTRACTION

Original reports obtained through a MEDLINE search for 1966 through 1992 on VLCDs or reducing diets plus obesity, supplemented by a manual search of bibliographies and the opinions of experts in the field of nutrition and weight loss therapy for obesity. Only studies of humans were cited.

DATA SYNTHESIS

Current VLCDs are usually provided in the context of comprehensive treatment programs, during which usual food intake is completely replaced by specific foods or liquid formulas containing 3350 kJ/d (800 kcal/d) or less. Weight loss on VLCDs averages 1.5 to 2.5 kg/wk; total loss after 12 to 16 weeks averages 20 kg. These results are superior to standard low-calorie diets of 5020 kJ/d (1200 kcal/d), which lead to weight losses of 0.4 to 0.5 kg/wk and an average total loss of only 6 to 8 kg. There is little evidence that intakes of less than 3350 kJ/d (800 kcal/d) result in better weight losses than 3350 kJ. Intake of at least 1 g/kg of ideal body weight per day of protein of high biologic value appears to be important in helping to preserve lean body mass. Serious complications of modern VLCDs are unusual, cholelithiasis being most common.

CONCLUSIONS

Current VLCDs are generally safe when used under proper medical supervision in moderately and severely obese patients (body mass index [weight in kilograms divided by height in meters squared] > 30) and are usually effective in promoting significant short-term weight loss, with concomitant improvement in obesity-related conditions. Long-term maintenance of weight lost with VLCDs is not very satisfactory and is no better than with other forms of obesity treatment. Incorporation of behavioral therapy and physical activity in VLCD treatment programs seems to improve maintenance.

The critical role of exercise in weight control

Exercise appears to play a critical role in the loss and maintenance of body weight. Diet alone has met with only temporary success because metabolic rate is decreased with extreme calorie restriction. This decrease persists after the dieting period has ended, often leading to rapid weight regain and the "yo-yo effect." In some instances, exercise alone has been effective for weight loss; however, success varies according to the gender of the subjects and to the type, intensity and duration of the exercise. Exercise programs of low to moderate intensity, long duration and high frequency seem to be most beneficial, with the most popular forms of exercise being walking/jogging, cycling and swimming. The purpose of this article is to explore the differences between diet and exercise, low vs. high intensity, short vs. long duration, and land vs. water exercise as these differences pertain to weight loss, food intake and energy balance.

The effects of aerobic exercise on psychological adjustment: a randomized study of sedentary obese women attempting weight loss

This study evaluated the psychological effects of aerobic conditioning in 40 moderately obese, sedentary women participating in a 12-week behavioral weight loss program. Participants were randomly assigned to a no-exercise or moderate walking condition. Emotional impact of the treatment was assessed in two ways: (1) Subjects reported subjective mood prior to each eating episode and (2) the SCL-90-R was administered before and after the program. Exercisers lost more weight and body fat than non-exercisers. Both groups of subjects showed numerous improvements in mood as a result of participating in the weight loss program. Exercise had no specific differential effect on emotions as measured by daily mood ratings or the SCL-90-R. Exercise did not appear to add appreciably to the psychological benefits of losing weight in this sedentary obese population. Future studies utilizing longer periods of aerobic exercise training, larger sample size, and exercise specific measures are recommended.

Achieving healthy weights

Only 5% of patients dieting to achieve permanent weight loss will be successful and reap the associated health benefits. Ninety-five percent will be unsuccessful. The health implications of failed dieting attempts are numerous and include negative effects on both physical and psychological well-being. Better alternatives to dieting help patients take small, positive, enjoyable steps toward healthy eating, active living, and a positive self-image.

The effect of a high protein-low calorie diet on the energy expenditure of obese adolescents

Resting energy expenditure (REE), and body composition, as fat-free mass (FFM) and fat mass, were determined in seven obese adolescents before and after weight loss of a mean 13.5 kg on an approximately 800 kcal/d (3349 kJ), high protein reducing diet regimen. Ideal body weight decreased from 166% to 142% in 8 weeks. There were no significant changes in total body potassium (TBK), extracellular water (ECW), intracellular water (ICW) or total body water (TBW) with weight loss. The REE (kcal/d) fell from 2034 +/- 392 (8514 +/- 1641 kJ) to 1762 +/- 453 (7376 +/- 1896 kJ) with weight loss (P < 0.05). However, when the REE was expressed as kcal/body weight there was no difference between before and after weight loss, 21.4 +/- 2.8 (90 +/- 21 kJ) and 21.6 +/- 4.5 (90 +/- 19 kJ). Similarly, when REE was examined in relation to FFM (kcal/kg) before and after weight loss, there were also no significant differences: 34.6 +/- 5.1 (145 +/- 21 kJ) and 32.1 +/- 7.9 (134 +/- 33 kJ).

Benefit from hypocaloric diet in obese men depends on the extent of weight-loss regarding cholesterol, and on a simultaneous change in body fat distribution regarding insulin sensitivity and glucose tolerance

Obesity and an android body fat distribution are related to metabolic disorders. We investigated the interdependences between metabolism, overweight, and body fat distribution in 40 moderately obese men before and after weight-loss. Correlations between metabolic parameters and body mass index (BMI) or waist to hip ratio (WHR) were much weaker in this exclusively obese population than in subjects of all weight categories, but the association between BMI and glucose tolerance (r = -.46, P less than .01) increased significantly after weight-loss. The improvement of metabolic parameters was much stronger in men who achieved normal weight (BMI less than 27 kg/m2) than in those who remained obese (BMI greater than 30 kg/m2, P less than .05). The WHR decreased during the diet (P less than .001), and this decrease and the extent of weight-loss were significantly correlated to an increase in insulin sensitivity (r = -.41, P less than .01) and a decrease in glucose area after an oral glucose load (r = .34, P less than .05). The decrease in apolipoprotein B, total cholesterol, and low-density lipoprotein (LDL) cholesterol was significantly correlated only to the extent of weight-loss (r = .34, .31, and .39, respectively; P less than .05). We conclude that it is best to reach normal weight for the normalization of metabolic aberrations. The reduction of cholesterol appears to be dependent on the extent of weight-loss, while the improvement in insulin sensitivity and glucose tolerance apparently is related to both the extent of weight-loss and to a change toward a less android body fat distribution.

Weight gain prevention and smoking cessation: cautionary findings

OBJECTIVES

Weight gain is a consistent sequela of smoking cessation. A successful intervention might attract smokers who fear weight gain. If the gain causes smoking relapse, such an intervention might reduce smoking relapse risk.

METHODS

Using a sample of 158 smokers who completed a 2-week smoking treatment program, we compared an innovative weight gain prevention intervention with both a nonspecific treatment and standard treatment. Subjects were assessed on weight and smoking behavior and followed for 1 year.

RESULTS

A disturbing, unexpected finding was that subjects in both the innovative and nonspecific conditions had a higher risk of smoking relapse than did standard treatment subjects. Some differences were observed between abstinent and smoking subjects in weight gain by treatment condition.

CONCLUSIONS

Both active interventions may have been so complicated that they detracted from nonsmoking. Also, caloric restriction may increase the reinforcing value of nicotine, a psychoactive drug, thereby increasing smoking relapse risk. The magnitude of weight gain after smoking cessation may not merit interventions that increase smoking risk. Perhaps attitudinal modifications are the most appropriate.

A multicenter evaluation of a proprietary weight reduction program for the treatment of marked obesity

BACKGROUND

Congressional hearings initiated in March 1990 revealed that America's $10 billion a year weight loss industry is subject to minimal regulation by federal agencies. Consumers are forced to rely on advertisements and testimonials when selecting treatment because no proprietary program has provided a prospective assessment of its short- and long-term results of treatment. This report describes such an assessment.

METHODS

A total of 517 obese patients (407 women and 110 men) participated in a proprietary program that included 12 weeks of treatment by very-low-calorie diet within a 26-week program of life-style modification. Patients were treated in two cohorts (6 months apart) according to a standardized protocol implemented at 18 hospital-based clinics across the nation.

RESULTS

Fifty-six percent of women and 54% of men completed treatment, at which time their weight losses (mean +/- SEM) were 22.0 +/- 0.6 and 32.1 +/- 1.4 kg, respectively. Weight losses of women and men who discontinued treatment averaged 14.3 +/- 0.7 and 20.0 +/- 1.6 kg, respectively. Weight loss was associated with significant improvements in blood pressure and total serum cholesterol levels. A 1-year follow-up evaluation of 74% of patients in the second cohort who completed treatment revealed that they maintained 15.3 +/- 1.2 of their 24.8 +/- 1.0-kg end-of-treatment weight loss; 59% of patients maintained a loss of 10 kg or more.

CONCLUSION

We hope that this report will lead to the systematic evaluation of other proprietary weight loss programs and to the publication of findings that will permit consumers to make informed treatment decisions.

[Over-the-counter weight-reducing preparations]

This report deals with over-the-counter products sold currently in Denmark for weight reduction. Only oral products (alternative medications and food supplements) are included. The report includes 35 such products. The aims of the report are to provide a common, factual basis for the debate about weight-reduction products and to present proposals for regulations that improve the conditions for patients and health professionals to make their choice of the optimal products. Current laws and administrative regulations are found to be complicated, obscure and inadequate. For most products, documentation for efficacy and safety is inadequate and health hazards are probable using several of the products. It is recommended 1) that obesity should be considered as a disease also in a legal/administrative context, 2) that an effective and objective registration of side-effects to alternative medication and food supplements is established, 3) that these products are tested for efficacy and safety before being marketed, 4) that the entire product information is made easily accessible, 5) that products without any documented effect are clearly labelled with this information and 6) that weight loss products involving health hazards are excluded from the market.

Thymulin activity during very-low-calorie diet

The potential use of thymulin levels as a sensitive and functional marker of energy deficiency was investigated in 13 obese women during a 3-week very-low-calorie diet. Mean weight loss was 8.92 +/- 0.52 kg after 21 days of treatment. The patients were free from infection as assessed by serum orosomucoid and C-reactive protein measurements. Serum albumin levels were not decreased throughout the experiment whereas transthyretin concentrations fell significantly during the first 2 weeks and remained fairly stable thereafter. Orosomucoid levels dropped only after 3 weeks of dieting. Serum zinc concentrations were within the normal range on admission and at the end of the experiment. Thymulin activity was not altered throughout the study, suggesting that this thymic hormone cannot be used as a functional marker of short-term energy restriction.

Government should strengthen regulation in the weight loss industry

Rationales for government regulation in the weight loss industry are developed on the basis of the concepts of market failure and potential harm to consumers. Evidence shows that consumers face problems in judging the quality of the industry's products and services, and they lack adequate protection against possible harm. The pros and cons of a variety of public and private strategies are examined for correcting these deficiencies. Recommendations are suggested for strengthening existing government regulations and expanding research.

Exercise and mild essential hypertension

The achievement of chronic blood pressure (BP) control in persons with mild hypertension is of central strategic concern in the prevention of hypertension-related morbidity and mortality. Epidemiologic and longitudinal studies suggest that regular participation in physical activity may be beneficial both in preventing hypertension and in lowering an already elevated BP. Moreover, preliminary analyses from our center suggest that cardiorespiratory fitness and, by inference, aerobic exercise may be of benefit in reducing mortality rates in hypertensive patients. When prescribing exercise with the intention of reducing an elevated BP and attenuating the risk for coronary artery disease, several factors must be considered to optimize the likelihood of a safe and effective response. These factors include specific safety aspects, and the type, frequency, intensity, and duration of exercise. In this respect, we recommend that aerobic exercise be performed at an intensity corresponding to 55 and 85% of the maximal heart rate and that the duration and frequency of training be modulated to achieve a weekly energy expenditure of between 14 and 20 kcal/kg of body weight. For those patients who require drug therapy, the interaction between the specific antihypertensive agent and exercise must also be considered.

Obesity and cardiovascular risk intervention through the ad libitum feeding of traditional Hawaiian diet

The Waianae Diet Program is a community-based intervention strategy designed to be culturally appropriate by using a pre-Western-contact Hawaiian diet to reduce chronic-disease risk factors in Native Hawaiians. This paper describes a trial of the traditional Hawaiian diet fed ad libitum to Native Hawaiians with multiple risk factors for cardiovascular disease to assess its effect on obesity and cardiovascular risk factors. Twenty Native Hawaiians were placed on a pre-Western-contact Hawaiian diet for 21 d. The diet was low in fat (7%), high in complex carbohydrates (78%), and moderate in protein (15%). Participants were encouraged to eat to satiety. Average energy intake decreased from 10.86 MJ (2594 kcal)/d to 6.57 MJ (1569 kcal)/d. Average weight loss was 7.8 kg (P less than 0.0001) and average serum cholesterol decreased 0.81 mmol/L (P less than 0.001) from 5.76 to 4.95 mmol/L. Blood pressure decreased an average of 11.5 mm Hg systolic (P less than 0.001) and 8.9 mm Hg diastolic (P less than 0.001).