A low-fat intake and greater activity level are associated with lower weight regain 3 years after completing a very-low-calorie diet

The challenge of keeping it off, a descriptive systematic review of high-quality, follow-up studies of obesity treatments

The aim of this systematic review is to answer the question: Is substantial, stable, and long-term weight loss a viable goal for adults with obesity? To answer this question, we conducted a broad systematic search of non-surgical and non-pharmacological obesity treatment studies with the following strict criteria: (a) minimum 3-year follow-up, (b) 5% body mass lost, (c) no continued interventions in the follow-up-period, (d) prospective design, and (e) less than 30% attrition from the start of the follow-up period. While the search revealed a very large number of published articles, only eight studies met the inclusion criteria. Several of the nonincluded studies report a majority of participants achieving satisfactory weight loss and little regain, especially among studies with continued interventions during the follow-up period. In contrast, the eight high-quality studies included in this study demonstrate a trend of weight regain towards pretreatment baseline. This review concludes that the majority of high-quality follow-up treatment studies of individuals with obesity are not successful in maintaining weight loss over time. The results suggest that excess weight can be lost but is likely regained over time, for the majority of participants.

Objectively Assessed Physical Activity and Weight Loss Maintenance among Individuals Enrolled in a Lifestyle Intervention

OBJECTIVE

To examine the relationship between objectively assessed moderate-to-vigorous intensity physical activity (MVPA) and 4-year weight loss (WL) and WL maintenance among individuals with diabetes enrolled in the Look AHEAD trial.

METHODS

MVPA was measured in a subgroup of lifestyle intervention participants with accelerometry data at baseline and at 1 and 4 years (n = 553; age: 59.7 ± 6.8 y; BMI: 35.5 ± 5.9 kg/m2 ). Minutes per week of bout-related MVPA were calculated (≥ 3 metabolic equivalents, ≥ 10-min bouts), and adherence to the national physical activity (PA) recommendation for WL maintenance (≥ 250 min/wk) was assessed.

RESULTS

Independent of 1-year WL, 4-year MVPA (β = -0.003, SE = 0.002, P = 0.006), but not 1-year MVPA (β = 0.0001, SE = 0.001, P = 0.50), was significantly associated with 4-year WL. Compared with "nonmaintainers" (≥ 10% WL at year 1, but < 10% at year 4; n = 132), WL maintainers (≥ 10% WL at years 1 and 4; n = 103) had higher MVPA at year 1 (253.4 ± 251.8 vs. 163.9 ± 158.2 min/wk, P = 0.002) and year 4 (155.3 ± 180.6 vs. 111.4 ± 154.5 min/wk, P = 0.046). Although 38.8% and 22.3% of WL maintainers engaged in ≥ 250 min/wk at years 1 and 4, respectively, many engaged in < 150 min/wk (year 1: 41%, year 4: 61%).

CONCLUSIONS

Higher weekly MVPA is associated with greater long-term WL and weight maintenance; however, many individuals are able to maintain ≥ 10% WL while engaging in little MVPA.

A Randomized Controlled Trial Translating the Diabetes Prevention Program to a University Worksite, Ohio, 2012-2014

Introduction

Working adults spend much time at the workplace, an ideal setting for wellness programs targeting weight loss and disease prevention. Few randomized trials have evaluated the efficacy of worksite diabetes prevention programs. This study evaluated the efficacy of a worksite lifestyle intervention on metabolic and behavioral risk factors compared with usual care.

Methods

A pretest–posttest control group design with 3-month follow-up was used. Participants with prediabetes were recruited from a university worksite and randomized to receive a 16-week lifestyle intervention (n = 35) or usual care (n = 34). Participants were evaluated at baseline, postintervention, and 3-month follow-up. Dietary intake was measured by a food frequency questionnaire and level of physical activity by accelerometers. Repeated measures analysis of variance compared the change in outcomes between and within groups.

Results

Mean (standard error [SE]) weight loss was greater in the intervention (−5.5% [0.6%]) than in the control (−0.4% [0.5%]) group (P < .001) postintervention and was sustained at 3-month follow-up (P < .001). Mean (SE) reductions in fasting glucose were greater in the intervention (−8.6 [1.6] mg/dL) than in the control (−3.7 [1.6] mg/dL) group (P = .02) postintervention; both groups had significant glucose reductions at 3-month follow-up (P < .001). In the intervention group, the intake of total energy and the percentage of energy from all fats, saturated fats, and trans fats decreased, and the intake of dietary fiber increased (all P < .01) postintervention.

Conclusion

The worksite intervention improved metabolic and behavioral risk factors among employees with prediabetes. The long-term impact on diabetes prevention and program sustainability warrant further investigation.

Neuroimaging studies of factors related to exercise: rationale and design of a 9 month trial

The prevalence of obesity is high resulting from chronic imbalances between energy intake and expenditure. On the expenditure side, regular exercise is associated with health benefits, including enhanced brain function. The benefits of exercise are not immediate and require persistence to be realized. Brain regions associated with health-related decisions, such as whether or not to exercise or controlling the impulse to engage in immediately rewarding activities (e.g., sedentary behavior), include reward processing and cognitive control regions. A 9 month aerobic exercise study will be conducted in 180 sedentary adults (n = 90 healthy weight [BMI = 18.5 to 26.0 kg/m(2)]; n = 90 obese [BMI = 29.0 to 41.0 kg/m(2)) to examine the brain processes underlying reward processing and impulse control that may affect adherence in a new exercise regimen. The primary aim is to use functional magnetic resonance imaging (fMRI) to examine reward processing and impulse control among participants that adhere (exercise >80% of sessions) and those that do not adhere to a nine-month exercise intervention with secondary analyses comparing sedentary obese and sedentary healthy weight participants. Our results will provide valuable information characterizing brain activation underlying reward processing and impulse control in sedentary obese and healthy weight individuals. In addition, our results may identify brain activation predictors of adherence and success in the exercise program along with measuring the effects of exercise and improved fitness on brain activation.

Positive effect of mushrooms substituted for meat on body weight, body composition, and health parameters. A 1-year randomized clinical trial

Reducing energy density (ED) of the diet is an important strategy for controlling obesity. This 1-year, randomized clinical trial examined the effect of substituting mushrooms for red meat ('mushroom diet'), compared to a standard diet ('meat diet'), on weight loss and maintenance among 73 obese adults (64 women, 9 men). The subjects completed anthropometric measurements and 7-day food records four times during a standardized weight loss and maintenance regimen. At the end of the 1-year trial, compared to participants on the standard diet, participants on the mushroom diet (n=36) reported lower intakes of energy (mean ± [SE]=-123 ± 113 kcals) and fat (-4.25 ± 6.88 g), lost more pounds and percentage body weight (-7.03 ± 3.34 lbs, 3.6%), achieved lower body mass index (-1.53 ± 0.36), waist circumference (-2.6 ± 3.5 in.) and percent total body fat (-0.85 ± 0.53), and had lower systolic and diastolic pressure (-7.9 and -2.5 mmHg); their lipid profile and inflammatory markers also improved. After initial weight loss, subjects following the mushroom diet maintained that loss well. Those who completed the full 12-month trial still weighed a mean of 7 lbs less than baseline. Thus, encouraging adults to substitute mushrooms for red meat was a useful strategy for enhancing weight loss, weight maintenance, and health parameters.

Amount of Food Group Variety Consumed in the Diet and Long-Term Weight Loss Maintenance

OBJECTIVE

Decreases in variety of foods consumed within high-fat-dense food groups and increases in variety of foods consumed within low-fat-dense food groups are associated with lower energy intake and greater weight loss during obesity treatment and may assist with weight loss maintenance. This study examined food group variety in 2237 weight loss maintainers in the National Weight Control Registry, who had lost 32.2 +/- 18.0 kg (70.9 +/- 39.5 lbs) and maintained a weight loss of at least 13.6 kg (30 lbs) for 6.1 +/- 7.7 years.

RESEARCH METHODS AND PROCEDURES

At entry into the registry, registry members completed a food frequency questionnaire from which amount of variety consumed from different food groups was assessed. To provide a context for interpreting the level of variety occurring in the diet of registry participants, food group variety was compared between registry participants and 96 individuals who had recently participated in a behavioral weight loss program and had lost at least 7% of initial body weight.

RESULTS

Registry members reported consuming a diet with very low variety in all food groups, especially in those food groups higher in fat density. Registry participants consumed significantly (p < 0.001) less variety within all food groups, except fruit and combination foods, than recent weight losers after 6 months of weight loss treatment.

DISCUSSION

These results suggest that successful weight loss maintainers consume a diet with limited variety in all food groups. Restricting variety within all food groups may help with consuming a low-energy diet and maintaining long-term weight loss.

Dietary macronutrients and food consumption as determinants of long-term weight change in adult populations: a systematic literature review

This systematic literature review examined the role of dietary macronutrient composition, food consumption and dietary patterns in predicting weight or waist circumference (WC) change, with and without prior weight reduction. The literature search covered year 2000 and onwards. Prospective cohort studies, case–control studies and interventions were included. The studies had adult (18–70 y), mostly Caucasian participants. Out of a total of 1,517 abstracts, 119 full papers were identified as potentially relevant. After a careful scrutiny, 50 papers were quality graded as A (highest), B or C. Forty-three papers with grading A or B were included in evidence grading, which was done separately for all exposure-outcome combinations. The grade of evidence was classified as convincing, probable, suggestive or no conclusion. We found probable evidence for high intake of dietary fibre and nuts predicting less weight gain, and for high intake of meat in predicting more weight gain. Suggestive evidence was found for a protective role against increasing weight from whole grains, cereal fibre, high-fat dairy products and high scores in an index describing a prudent dietary pattern. Likewise, there was suggestive evidence for both fibre and fruit intake in protection against larger increases in WC. Also suggestive evidence was found for high intake of refined grains, and sweets and desserts in predicting more weight gain, and for refined (white) bread and high energy density in predicting larger increases in WC. The results suggested that the proportion of macronutrients in the diet was not important in predicting changes in weight or WC. In contrast, plenty of fibre-rich foods and dairy products, and less refined grains, meat and sugar-rich foods and drinks were associated with less weight gain in prospective cohort studies. The results on the role of dietary macronutrient composition in prevention of weight regain (after prior weight loss) were inconclusive.

Intervening on spontaneous physical activity to prevent weight regain in older adults: design of a randomized, clinical trial

There is a need to identify evidenced-based obesity treatments that are effective in maintaining lost weight. Weight loss results in reductions in energy expenditure, including spontaneous physical activity (SPA) which is defined as energy expenditure resulting primarily from unstructured mobility-related activities that occur during daily life. To date, there is little research, especially randomized, controlled trials, testing strategies that can be adopted and sustained to prevent declines in SPA that occur with weight loss. Self-monitoring is a successful behavioral strategy to facilitate behavior change, so a provocative question is whether monitoring SPA-related energy expenditure would override these reductions in SPA, and slow weight regain. This study is a randomized trial in older, obese men and women designed to test the hypothesis that adding a self-regulatory intervention (SRI), focused around self-monitoring of SPA, to a weight loss intervention will result in less weight and fat mass regain following weight loss than a comparable intervention that lacks this self-regulatory behavioral strategy. Participants (n=72) are randomized to a 5-month weight loss intervention with or without the addition of a behavioral component that includes an innovative approach to promoting increased SPA. Both groups then transition to self-selected diet and exercise behavior for a 5-month follow-up. Throughout the 10-month period, the SRI group is provided with an intervention designed to promote a SPA level that is equal to or greater than each individual's baseline SPA level, allowing us to isolate the effects of the SPA self-regulatory intervention component on weight and fat mass regain.

Effect of a low fat versus a low carbohydrate weight loss dietary intervention on biomarkers of long term survival in breast cancer patients ('CHOICE'): study protocol

Background

Weight loss in overweight or obese breast cancer patients is associated with an improved prognosis for long term survival. However, it is not clear whether the macronutrient composition of the chosen weight loss dietary plan imparts further prognostic benefit. A study protocol is presented for a dietary intervention to investigate the effects of weight loss dietary patterns that vary markedly in fat and carbohydrate contents on biomarkers of exposure to metabolic processes that may promote tumorigenesis and that are predictive of long term survival. The study will also determine how much weight must be lost for biomarkers to change in a favorable direction.

Methods/Design

Approximately 370 overweight or obese postmenopausal breast cancer survivors (body mass index: 25.0 to 34.9 kg/m²) will be accrued and assigned to one of two weight loss intervention programs or a non-intervention control group. The dietary intervention is implemented in a free living population to test the two extremes of popular weight loss dietary patterns: a high carbohydrate, low fat diet versus a low carbohydrate, high fat diet. The effects of these dietary patterns on biomarkers for glucose homeostasis, chronic inflammation, cellular oxidation, and steroid sex hormone metabolism will be measured. Participants will attend 3 screening and dietary education visits, and 7 monthly one-on-one dietary counseling and clinical data measurement visits in addition to 5 group visits in the intervention arms. Participants in the control arm will attend two clinical data measurement visits at baseline and 6 months. The primary outcome is high sensitivity C-reactive protein. Secondary outcomes include interleukin-6, tumor necrosis factor-α, insulin-like growth factor-1 (IGF), IGF binding protein-3, 8-isoprostane-F2-alpha, estrone, estradiol, progesterone, sex hormone binding globulin, adiponectin, and leptin.

Discussion

While clinical data indicate that excess weight for height is associated with poor prognosis for long term survival, little attention is paid to weight control in the clinical management of breast cancer. This study will provide information that can be used to answer important patient questions about the effects of dietary pattern and magnitude of weight loss on long term survival following breast cancer treatment.

Clinical Trial Registration

CA125243

Pre-pregnancy and pregnancy predictors of obesity

Obesity has progressively become a global epidemic that constitutes one of the biggest current health problems worldwide. Pregnancy is a risk factor for excessive weight gain. Factors that may predict development of obesity in later life mainly include gestational weight gain, pre-pregnancy nutritional status, age, parity and race. Change in lifestyle factors, such as eating habits, enrollment in physical activity, smoking and duration of lactation, in addition to the above factors, may also contribute to the development of obesity but are still not fully understood. Women who retain more body weight after pregnancy have, in general, larger pregnancy body weight gain, higher pre-pregnancy body mass index, marked weight changes in previous pregnancies, lactate slightly less and stop smoking during pregnancy to a larger extent. In addition, irregular eating habits and decreased leisure time activity after delivery influence postpartum weight retention. Taking into consideration the epidemic of obesity, with all its adverse long-term consequences, there is an increasing need to promote counseling before, during and after pregnancy on the role of diet and physical activity in reproductive health.

Contribution of behavior intervention components to 24-month weight loss

Sustaining weight loss at the long term is difficult.

PURPOSE

To examine if eating behaviors, physical activity levels, and program participation influence ones ability to achieve ≥5%, ≥7%, and ≥10% weight loss during a period of 24 months.

METHODS

Data from 170 overweight and obese women (body mass index = 32.7 ± 4.2 kg·m(-2)) were analyzed in this study. All women followed a standard 24-month behavioral weight loss program in which they were instructed to decrease caloric intake and increase physical activity levels. Eating behaviors, body weight, and physical activity levels were assessed at baseline and at 6 and 24 months. Program participation was evaluated by the percentage of group meetings attended and the percentage of telephone calls completed with an interventionist. Three separate stepwise linear regression analyses were performed to identify variables that were predictive of ≥5%, ≥7%, and ≥10% weight loss at 24 months.

RESULTS

The percentage of telephone calls completed and change in weight loss eating behaviors predicted ≥5% (r2 = 0.16), ≥7% (r2 = 0.14), and ≥10% weight loss (r2 = 0.10) at 24 months. However, the change in physical activity levels from baseline to 24 months was only predictive of weight losses ≥10% (r2 = 0.11).

CONCLUSIONS

Behavioral factors, such as adopting healthy eating behaviors and telephone contact time, are important components that assist individuals in achieving weight losses ≥5%. However, high levels of physical activity play a more prominent role in sustaining weight losses ≥10%. Therefore, innovative strategies to enhance long-term exercise adherence should be developed.

Effects of caloric restriction with varying energy density and aerobic exercise on weight change and satiety in young female adults

This study examines the combined effects of caloric restriction on body composition, blood lipid, and satiety in slightly overweight women by varying food density and aerobic exercise. Twenty-three women were randomly assigned to one of two groups for a four-week weight management program: the high-energy density diet plus exercise (HDE: n = 12, 22 ± 2 yrs, 65 ± 7 kg, 164 ± 5 cm, 35 ± 4 % fat) and low-energy density diet plus exercise (LDE: n = 11, 22 ± 1 yrs, 67 ± 7 kg, 161 ± 2 cm, 35 ± 4 % fat) groups. Subjects maintained a low-calorie diet (1,500 kcal/day) during the program. Isocaloric (483 ± 26 for HDE, 487 ± 27 kcal for LDE) but different weight (365 ± 68 for HDE, 814 ± 202 g for LDE) of lunch was provided. After lunch, they biked at 60% of maximum capacity for 40 minutes, five times per week. The hunger level was scaled (1: extremely hungry; 9: extremely full) at 17:30 each day. Before and after the program, the subjects' physical characteristics were measured, and fasting blood samples were drawn. The daily energy intake was 1,551 ± 259 for HDE and 1,404 ± 150 kcal for LDE (P > 0.05). After four weeks, the subjects' weights and % fat decreased for both LDE (-1.9 kg and -1.5%, P < 0.05) and HDE (-1.6 kg and -1.4%, respectively, P < 0.05). The hunger level was significantly higher for HDE (2.46 ± 0.28) than for LDE (3.10 ± 0.26) (P < 0.05). The results suggest that a low-energy density diet is more likely to be tolerated than a high-energy density diet for a weight management program combining a low-calorie diet and exercise, mainly because of a reduced hunger sensation.

Pmch expression during early development is critical for normal energy homeostasis

Postnatal development and puberty are times of strong physical maturation and require large quantities of energy. The hypothalamic neuropeptide melanin-concentrating hormone (MCH) regulates nutrient intake and energy homeostasis, but the underlying mechanisms are not completely understood. Here we use a novel rat knockout model in which the MCH precursor Pmch has been inactivated to study the effects of loss of MCH on energy regulation in more detail. Pmch(-/-) rats are lean, hypophagic, osteoporotic, and although endocrine parameters were changed in pmch(-/-) rats, endocrine dynamics were normal, indicating an adaptation to new homeostatic levels rather than disturbed metabolic mechanisms. Detailed body weight growth and feeding behavior analysis revealed that Pmch expression is particularly important during early rat development and puberty, i.e., the first 8 postnatal weeks. Loss of Pmch resulted in a 20% lower set point for body weight that was determined solely during this period and remained unchanged during adulthood. Although the final body weight is diet dependent, the Pmch-deficiency effect was similar for all diets tested in this study. Loss of Pmch affected energy expenditure in both young and adult rats, although these effects seem secondary to the observed hypophagia. Our findings show an important role for Pmch in energy homeostasis determination during early development and indicate that the MCH receptor 1 system is a plausible target for childhood obesity treatment, currently a major health issue in first world countries.

The effect of physical activity on body weight

There is evidence to support that low fitness and physical activity, excess body weight, and excess abdominal fatness are associated with increased health risk. Moreover, evidence exists to support that sufficient levels of physical activity can significantly improve body weight, fatness, and health risk. Physical activity has been shown to have a modest effect on body weight that is typically <3% of initial body weight, but has an additive effect when combined with dietary restriction. Moreover, physical activity has been shown to be an important behavioral factor for enhancing long-term weight loss and minimizing weight regain; however, this may require relatively high doses of physical activity that approach 300 min/week. Physical activity may concurrently reduce abdominal adiposity, and which may serve as a pathway by which there is also an improvement in health-related risk factors for various chronic diseases. There are important areas of research that require further investigation, with particular need to further examine the dose of physical activity that significantly affects these health outcomes. Moreover, there is a need for improved interventions to promote the adoption and long-term maintenance of physical activity, which can lead to improved weight control, abdominal adiposity, and chronic disease risk factors. Future research is also needed to understand the physiological/metabolic pathways and mechanisms that explain the influence of physical activity on long-term regulation of body weight.

Weight regain is related to decreases in physical activity during weight loss

PURPOSE

To examine whether adaptations in physical activity energy expenditure (PAEE) and resting metabolic rate (RMR) during weight loss were associated with future weight regain in overweight/obese, older women.

RESEARCH METHODS AND PROCEDURES

Thirty-four overweight/obese (BMI = 25-40 kg x m(-2)), postmenopausal women underwent a 20-wk weight loss intervention of hypocaloric diet with (low- or high-intensity) or without treadmill walking (weekly caloric deficit was approximately 11,760 kJ), with a subsequent 12-month follow-up. RMR (via indirect calorimetry), PAEE (by RT3 accelerometer), and body composition (by dual-energy x-ray absorptiometry) were measured before and after intervention. Body weight and self-reported information on physical activity were collected after intervention and at 6 and 12 months after intervention.

RESULTS

The intervention resulted in decreases in body weight, lean mass, fat mass, percent body fat, RMR, and PAEE (P < 0.001 for all). Weight regain was 2.9 +/- 3.3 kg (-3.1 to +9.2 kg) at 6 months and 5.2 +/- 5.0 kg (-2.3 to +21.7 kg) at 12 months after intervention. The amount of weight regained after 6 and 12 months was inversely associated with decreases in PAEE during the weight loss intervention (r = -0.521, P = 0.002 and r = -0.404, P = 0.018, respectively), such that women with larger declines in PAEE during weight loss experienced greater weight regain during follow-up. Weight regain was not associated with changes in RMR during intervention or with self-reported physical activity during follow-up.

CONCLUSION

This study demonstrates that although both RMR and PAEE decreased during weight loss in postmenopausal women, maintaining high levels of daily physical activity during weight loss may be important to mitigate weight regain after weight loss.

Alteration of dietary fat intake to prevent weight gain: Jayhawk Observed Eating Trial

OBJECTIVE

To examine the effects of ad libitum diets with three distinct levels of fat intake for the prevention of weight gain in sedentary, normal-weight and overweight men and women.

METHODS AND PROCEDURES

Three hundred and five participants were randomized to one of three diets. The diets targeted <25% of energy from fat (low fat (LF)), between 28 and 32% of energy from fat (moderate fat (MF)), or >35% of energy from fat (high fat (HF)). Participants consumed two meals per day on weekdays and one meal per day on weekends in a university cafeteria over a 12-week period. Energy and nutrient content of cafeteria foods were measured by digital photography. All meals and snacks consumed outside the cafeteria were measured by dietary recall. All analysis of energy and nutrient content was completed using Nutrition Data System for Research (NDS-R) version 2005.

RESULTS

Two hundred and sixty participants completed the study. LF gained 0.1 +/- 3.1 kg, MF gained 0.8 +/- 2.5 kg, and HF gained 1.0 +/- 2.2 kg and there was no gender or age effect. Longitudinal mixed modeling indicated a significant difference among the groups in weight over time (P = 0.0366). When adjusting for total energy intake, which was a significant predictor of weight over time, the global effect for the group was eliminated. Thus, increasing weight was a function of increasing energy but not increasing percentage of fat intake.

DISCUSSION

Energy intake, but not percentage of energy from fat, appears responsible for the observed weight gain. LF diets may contribute to weight maintenance and HF diets may promote weight gain due to the influence of fat intake on total energy intake.

A two-year randomized weight loss trial comparing a vegan diet to a more moderate low-fat diet

OBJECTIVE

The objective was to assess the effect of a low-fat, vegan diet compared with the National Cholesterol Education Program (NCEP) diet on weight loss maintenance at 1 and 2 years.

RESEARCH METHODS AND PROCEDURES

Sixty-four overweight, postmenopausal women were randomly assigned to a vegan or NCEP diet for 14 weeks, and 62 women began the study. The study was done in two replications. Participants in the first replication (N = 28) received no follow-up support after the 14 weeks, and those in the second replication (N = 34) were offered group support meetings for 1 year. Weight and diet adherence were measured at 1 and 2 years for all participants. Weight loss is reported as median (interquartile range) and is the difference from baseline weight at years 1 and 2.

RESULTS

Individuals in the vegan group lost more weight than those in the NCEP group at 1 year [-4.9 (-0.5, -8.0) kg vs. -1.8 (0.8, -4.3); p < 0.05] and at 2 years [-3.1 (0.0, -6.0) kg vs. -0.8 (3.1, -4.2) kg; p < 0.05]. Those participants offered group support lost more weight at 1 year (p < 0.01) and 2 years (p < 0.05) than those without support. Attendance at meetings was associated with improved weight loss at 1 year (p < 0.001) and 2 years (p < 0.01).

DISCUSSION

A vegan diet was associated with significantly greater weight loss than the NCEP diet at 1 and 2 years. Both group support and meeting attendance were associated with significant weight loss at follow-up.

Nutritional consequences of weight-loss surgery

Nutritional deficiencies are already present in many morbidly obese patients before weight-loss surgery. Appropriate preoperative detection and correction is essential. The severity and pattern of deficiencies is dependent on the presence of preoperative uncorrected deficiency, the type of procedure performed varying with the degree of restriction or the length of bypassed small intestine, the modification of eating behavior, the development of complications, compliance with oral multivitamin and mineral supplementation, and compliance with follow-up. Rigorous control of fluids and electrolytes with establishment of adequate oral nutrition is important in the immediate postoperative period. Regular follow-up of the metabolic and nutritional status of the patient is essential, with life-long multivitamin and mineral supplementation.

The role of diet and exercise for the maintenance of fat-free mass and resting metabolic rate during weight loss

The incidence of obesity is increasing rapidly. Research efforts for effective treatment strategies still focus on diet and exercise programmes, the individual components of which have been investigated in intervention trials in order to determine the most effective recommendations for sustained changes in bodyweight. The foremost objective of a weight-loss trial has to be the reduction in body fat leading to a decrease in risk factors for metabolic syndrome. However, a concomitant decline in lean tissue can frequently be observed. Given that fat-free mass (FFM) represents a key determinant of the magnitude of resting metabolic rate (RMR), it follows that a decrease in lean tissue could hinder the progress of weight loss. Therefore, with respect to long-term effectiveness of weight-loss programmes, the loss of fat mass while maintaining FFM and RMR seems desirable. Diet intervention studies suggest spontaneous losses in bodyweight following low-fat diets, and current data on a reduction of the carbohydrate-to-protein ratio of the diet show promising outcomes. Exercise training is associated with an increase in energy expenditure, thus promoting changes in body composition and bodyweight while keeping dietary intake constant. The advantages of strength training may have greater implications than initially proposed with respect to decreasing percentage body fat and sustaining FFM. Research to date suggests that the addition of exercise programmes to dietary restriction can promote more favourable changes in body composition than diet or physical activity on its own. Moreover, recent research indicates that the macronutrient content of the energy-restricted diet may influence body compositional alterations following exercise regimens. Protein emerges as an important factor for the maintenance of or increase in FFM induced by exercise training. Changes in RMR can only partly be accounted for by alterations in respiring tissues, and other yet-undefined mechanisms have to be explored. These outcomes provide the scientific rationale to justify further randomised intervention trials on the synergies between diet and exercise approaches to yield favourable modifications in body composition.

BRIEF REPORT: nutrition and weight loss information in a popular diet book: is it fact, fiction, or something in between?

BACKGROUND/OBJECTIVE

Diet books dominate the New York Times Advice Best Seller list and consumers cite such books as an important source of nutrition information. However, the scientific support for nutrition claims presented as fact (nutrition facts) in diet books is not known.

DESIGN/MEASUREMENTS

We assessed the quality of nutrition facts in the best-selling South Beach Diet using support in peer-reviewed literature as a measure of quality. We performed structured literature searches on nutrition facts located in the books' text, and then assigned each fact to 1 of 4 categories (1) fact supported, (2) fact not supported, (3) fact both supported and not supported, and (4) no related papers. A panel of expert reviewers adjudicated the findings.

RESULTS

Forty-two nutrition facts were included. Fourteen (33%) facts were supported, 7 (17%) were not supported, 18 (43%) were both supported and not supported, and 3 (7%) had no related papers, including the fact that the diet had been "scientifically studied and proven effective."

CONCLUSIONS

Consumers obtain nutrition information from diet books. We found that over 67% of nutrition facts in a best-seller diet book may not be supported in the peer-reviewed literature. These findings have important implications for educating consumers about nutrition information sources.

Who succeeds in maintaining weight loss? A conceptual review of factors associated with weight loss maintenance and weight regain

Weight loss is difficult to achieve and maintaining the weight loss is an even greater challenge. The identification of factors associated with weight loss maintenance can enhance our understanding for the behaviours and prerequisites that are crucial in sustaining a lowered body weight. In this paper we have reviewed the literature on factors associated with weight loss maintenance and weight regain. We have used a definition of weight maintenance implying intentional weight loss that has subsequently been maintained for at least 6 months. According to our review, successful weight maintenance is associated with more initial weight loss, reaching a self-determined goal weight, having a physically active lifestyle, a regular meal rhythm including breakfast and healthier eating, control of over-eating and self-monitoring of behaviours. Weight maintenance is further associated with an internal motivation to lose weight, social support, better coping strategies and ability to handle life stress, self-efficacy, autonomy, assuming responsibility in life, and overall more psychological strength and stability. Factors that may pose a risk for weight regain include a history of weight cycling, disinhibited eating, binge eating, more hunger, eating in response to negative emotions and stress, and more passive reactions to problems.