Weight maintenance: challenges,tools and strategies for primary care physicians

Obesity is recognized as a chronic disease and one of the major healthcare challenges facing us today. Weight loss can be achieved via lifestyle, pharmacological and surgical interventions, but weight maintenance remains a lifetime challenge for individuals with obesity. Guidelines for the management of obesity have highlighted the role of primary care providers (PCPs). This review examines the long‐term outcomes of clinical trials to identify effective weight maintenance strategies that can be utilized by PCPs. Because of the broad nature of the topic, a structured PubMed search was conducted to identify relevant research articles, peer‐reviewed reviews, guidelines and articles published by regulatory bodies. Trials have demonstrated the benefit of sustained weight loss in managing obesity and its comorbidities. Maintaining 5–10% weight loss for ≥1 year is known to ameliorate many comorbidities. Weight maintenance with lifestyle modification – although challenging – is possible but requires long‐term support to reinforce diet, physical activity and behavioural changes. The addition of pharmacotherapy to lifestyle interventions promotes greater and more sustained weight loss. Clinical evidence and recently approved pharmacotherapy has given PCPs improved strategies to support their patients with maintenance of weight loss. Further studies are needed to assess the translation of these strategies into clinical practice.     

Effect of diet‐induced weight loss on muscle strength in adults with overweight or obesity – a systematic review and meta‐analysis of clinical trials

We conducted a systematic review and meta‐analysis to identify how diet‐induced weight loss in adults with overweight or obesity impacts on muscle strength. Twenty‐seven publications, including 33 interventions, most of which were 8–24 weeks in duration, were included. Meta‐analysis of seven interventions measuring knee extensor strength by isokinetic dynamometry in 108 participants found a significant decrease following diet‐induced weight loss (?9.0 [95% confidence interval: ?13.8, ?4.1] N/m, P < 0.001), representing a 7.5% decrease from baseline values. Meta‐analysis of handgrip strength from 10 interventions in 231 participants showed a non‐significant decrease (?1.7 [?3.6, 0.1] kg, P = 0.070), with significant heterogeneity (I² = 83.9%, P < 0.001). This heterogeneity may have been due to diet type, because there was a significant decrease in handgrip strength in seven interventions in 169 participants involving moderate energy restriction (?2.4 [?4.8, ?0.0] kg, P = 0.046), representing a 4.6% decrease from baseline values, but not in three interventions in 62 participants involving very‐low‐energy diet (?0.4 [?2.0, 1.2] kg, P = 0.610). Because of variability in methodology and muscles tested, no other data could be meta‐analyzed, and qualitative assessment of the remaining interventions revealed mixed results. Despite varying methodologies, diets and small sample sizes, these findings suggest a potential adverse effect of diet‐induced weight loss on muscle strength. While these findings should not act as a deterrent against weight loss, due to the known health benefits of losing excess weight, they call for strategies to combat strength loss – such as weight training and other exercises – during diet‐induced weight loss. © 2016 World Obesity     

Very low energy diets in the treatment of obesity

Very low energy diets (VLEDs) are defined as diets which contain energy levels of less than 3.4 MJ (800 kcal) per day and contain daily allowances of all essential nutritional requirements. These diets have been in clinical use for more than 20 years. They are used as the only source of nutrition for 8–16 weeks, which usually achieves a weight loss of 1.5–2.5 kg per week. Before using this type of diet a medical investigation is necessary to evaluate contraindications and to check medication use during the diet. To facilitate maintenance, cognitive behavioural counselling should always be included in a weight reduction programme using a very low energy diet. VLEDs have no serious harmful effects and can safely be used in patients with various chronic diseases. Programmes using VLEDs produce better short‐term weight loss than programmes without the diet. However, in randomized controlled trials VLED‐based programmes have not achieved significantly better long‐term maintenance than conventional programmes. VLEDs are used when rapid weight loss is necessary because of an obesity‐related disease. In other patients with obesity it is an alternative to other conservative approaches for treatment of obesity. In type 2 diabetes it may improve long‐term glucose metabolism better than conventional weight reducing diets. Some studies suggest that after a VLED‐based programme long‐term maintenance is better among men than women. This possible gender difference is an important topic for further research.     

Is there an optimal macronutrient mix for weight loss and weight maintenance?

Low carbohydrate diets are gaining popularity, however there is no clear consensus regarding their safety and efficacy for weight loss. Proponents of these diet plans advocate dramatic reductions in carbohydrate intake to combat insulin resistance and hyperinsulinaemia, which they claim are responsible for obesity. There are no long-term studies that directly compare the weight loss potential of low versus higher carbohydrate diets. Evidence from randomized controlled trials suggests that low carbohydrate diets may enable short-term weight loss by facilitating reduced energy intakes, however poor dietary compliance may prevent long-term success. Unbalanced nutrient profiles may increase the risk of adverse health consequences in adherents. Low carbohydrate diets should not be recommended at this time due to a lack of adequate long-term follow up data. Successful weight loss occurs through the creation of a sustained energy deficit, and should be achieved through a combination of exercise and a nutritionally balanced and varied diet.     

Effects of nonnutritive sweeteners on body weight and BMI in diverse clinical contexts: Systematic review and meta‐analysis

There is an ongoing debate about the possible influences of nonnutritive sweeteners (NNS) on body weight. We conducted a systematic review and meta‐analysis of randomized controlled trials (RCTs) with NNS to assess their impact on body weight. We systematically searched for RCTs at least 4 weeks in duration, evaluating the effect of NNS on body weight, both in subjects with healthy weight and in subjects with overweight/obesity at any age, and compared the effects of NNS vs caloric and noncaloric comparators. The primary outcome was the difference in body weight between NNS and comparators. Twenty studies were eligible (n = 2914). Participants consuming NNS showed significant weight/BMI differences favouring NNS compared with nonusers. Grouping by nature of comparator revealed that NNS vs placebo/no intervention and NNS vs water produced no effect. When comparing NNS vs sucrose, significant weight/BMI differences appeared favouring NNS. Consumption of NNS led to significantly negative weight/BMI differences in unrestricted energy diets, but not in weight‐reduction diets. Participants with overweight/obesity and adults showed significant favourable weight/BMI differences with NNS. Data suggest that replacing sugar with NNS leads to weight reduction, particularly in participants with overweight/obesity under an unrestricted diet, information that could be utilized for evidence‐based public policy decisions.     

Do ketogenic diets really suppress appetite? A systematic review and meta‐analysis

Very‐low‐energy diets (VLEDs) and ketogenic low‐carbohydrate diets (KLCDs) are two dietary strategies that have been associated with a suppression of appetite. However, the results of clinical trials investigating the effect of ketogenic diets on appetite are inconsistent. To evaluate quantitatively the effect of ketogenic diets on subjective appetite ratings, we conducted a systematic literature search and meta‐analysis of studies that assessed appetite with visual analogue scales before (in energy balance) and during (while in ketosis) adherence to VLED or KLCD. Individuals were less hungry and exhibited greater fullness/satiety while adhering to VLED, and individuals adhering to KLCD were less hungry and had a reduced desire to eat. Although these absolute changes in appetite were small, they occurred within the context of energy restriction, which is known to increase appetite in obese people. Thus, the clinical benefit of a ketogenic diet is in preventing an increase in appetite, despite weight loss, although individuals may indeed feel slightly less hungry (or more full or satisfied). Ketosis appears to provide a plausible explanation for this suppression of appetite. Future studies should investigate the minimum level of ketosis required to achieve appetite suppression during ketogenic weight loss diets, as this could enable inclusion of a greater variety of healthy carbohydrate‐containing foods into the diet.     

The effect of non‐surgical weight loss interventions on urinary incontinence in overweight women: a systematic review and meta‐analysis

Although the aetiology of urinary incontinence can be multifactorial, in some cases weight loss could be considered as a part of the therapeutic approach for urinary incontinence in people who are overweight. The objective of this study was to review and meta‐analyse the effect of non‐surgical weight loss interventions on urinary incontinence in overweight women. Web of Science, PubMed, Pedro, SPORTDiscus and Cochrane were systematically searched for clinical trials that met the a priori set criteria. Data of women who participated in non‐surgical weight loss interventions (diet, exercise, medication or a combination) were included in the meta‐analysis. After removing duplicates, 62 articles remained for screening on title, abstract and full text. Six articles (totalling 2,352 subjects in the intervention groups) were included for meta‐analysis. The mean change in urinary incontinence (reported as frequency or quantity, depending on the study) after a non‐surgical weight loss intervention, expressed as standardized effect size and corrected for small sample sizes (Hedges' g), was ?0.30 (95%CI = ?0.47 to ?0.12). This systematic review and meta‐analysis shows evidence that a non‐surgical weight loss intervention has the potential to improve urinary incontinence and should be considered part of standard practice in the management of urinary incontinence in overweight women.     

Experiences of using very low energy diets for weight loss by people with overweight or obesity: a review of qualitative research

Although very low energy diets (VLEDs) are the most successful non‐surgical, non‐pharmacological treatment for obesity, they are underutilized, and little is known about experiences of people using VLEDs for weight loss. This systematic review synthesizes qualitative studies investigating participants' experiences of undertaking a VLED composed of total meal replacement products to lose weight. Of the 4,911 articles screened, three studies met criteria for inclusion. Thematic synthesis was used to analyse the study findings. Health and appearance were the main motivators to use a VLED for weight loss. Adherence was facilitated by group support meetings, rapid weight loss and ease of use of the diet. Being part of a clinical trial gave a sense of accountability and further reason to adhere to a VLED, and the VLED itself was well accepted by users. Barriers to adherence, such as temptations and social occasions, were overcome by avoidance and distraction strategies. In conclusion, this qualitative synthesis of users' experiences of VLEDs shows that VLEDs are well accepted and positively viewed by users. More in‐depth research could facilitate understanding of how this weight loss strategy influences the weight maintenance period, in order to facilitate better long‐term results.     

Dietary fat plays a major role in obesity: no

The percentage of dietary energy from fat has been suggested to be an important determinant of body fat, and this presumed effect has been invoked to justify the general promotion of low‐fat diets. Dietary fat and the prevalence of obesity are lower in poor countries than in affluent countries. However, these contrasts are seriously confounded by differences in physical activity and food availability; within areas of similar economic development, per capita intake of fat and the prevalence of obesity have not been positively correlated. Randomized trials are the preferable method for evaluating the effect of dietary fat on adiposity because they avoid problems of confounding that are difficult to control in other studies. In short‐term trials, a small reduction in body weight is typically seen in individuals randomized to diets with a lower percentage of calories from fat. In a meta‐analysis of these trials, it was estimated that a decrease in 10% of energy from fat would reduce weight by 16 g d^–1, which would correspond to a 9‐kg weight loss by 18 months. However, compensatory mechanisms appear to operate because in trials lasting one year or longer, fat consumption within the range of 18–40% of energy has consistently had little, if any, effect on body fatness. Moreover, within the United States (US), a substantial decline in the percentage of energy from fat during the last two decades has corresponded with a massive increase in obesity, and similar trends are occurring in other affluent countries. Diets high in fat do not account for the high prevalence of excess body fat in Western countries; reductions in the percentage of energy from fat will have no important benefits and could further exacerbate this problem. The emphasis on total fat reduction has been a serious distraction in efforts to control obesity and improve health in general.     

The role of dietary fat in obesity

Current scientific evidence indicates that dietary fat plays a role in weight loss and maintenance. Meta-analyses of intervention trials find that fat-reduced diets cause a 3-4-kg larger weight loss than normal-fat diets. A 10% reduction in dietary fat can cause a 4-5-kg weight loss in individuals with initial body mass index of 30 kg m (-2). Short-term trials show that nonfat dietary components are equally important. Sugar-sweetened beverages promote weight gain, and replacement of energy from fat by sugar-sweetened beverages is counterproductive in diets aimed at weight loss. Protein has been shown to be more satiating than carbohydrate, and fat-reduced diets with a high protein content (20-25% of energy) may increase weight loss significantly. There is little evidence that low-glycemic index foods facilitate weight control. Evidence linking certain fatty acids to body fatness is weak. Monounsaturated fatty acids may even be more fattening than polyunsaturated and saturated fats. No ad libitum dietary intervention study has shown that a normal-fat, high-monounsaturated fatty acid diet is comparable to a low-fat diet in preventing weight gain. Current evidence indicates that the best diet for prevention of weight gain, obesity, type 2 diabetes, and cardiovascular disease is low in fat and sugar-rich beverages and high in carbohydrates, fiber, grains, and protein.     

Achieving a clinically relevant composite outcome of an HbA1c of <7% without weight gain or hypoglycaemia in type 2 diabetes: a meta-analysis of the liraglutide clinical trial programme

Aim: Effective type 2 diabetes management requires a multifactorial approach extending beyond glycaemic control. Clinical practice guidelines suggest targets for HbA1c, blood pressure and lipids, and emphasize weight reduction and avoiding hypoglycaemia. The phase 3 clinical trial programme for liraglutide, a human glucagon‐like peptide 1 analogue, showed significant improvements in HbA1c and weight with a low risk of hypoglycaemia compared to other diabetes therapies. In this context, we performed a meta‐analysis of data from these trials evaluating the proportion of patients achieving a clinically relevant composite measure of diabetes control consisting of an HbA1c <7% without weight gain or hypoglycaemia. Methods: A prespecified meta‐analysis was performed on 26‐week patient‐level data from seven trials (N = 4625) evaluating liraglutide with commonly used therapies for type 2 diabetes: glimepiride, rosiglitazone, glargine, exenatide, sitagliptin or placebo, adjusting for baseline HbA1c and weight, for a composite outcome of HbA1c <7.0%, no weight gain and no hypoglycaemic events. Results: At 26 weeks, 40% of the liraglutide 1.8 mg group, 32% of the liraglutide 1.2 mg group and 6–25% of comparators (6% rosiglitazone, 8% glimepiride, 15% glargine, 25% exenatide, 11% sitagliptin, 8% placebo) achieved this composite outcome. Odds ratios favoured liraglutide 1.8 mg by 2.0‐ to 10.5‐fold over comparators. Conclusions: As assessed by the composite outcome of HbA1c <7%, no hypoglycaemia and no weight gain, liraglutide was clearly superior to the other commonly used therapies. However, the long‐term clinical impact of this observation remains to be shown.     

The role of the Mediterranean diet on weight loss and obesity-related diseases

Pandemic obesity is a major public health problem because of its association with non-communicable diseases and all-cause mortality, which can be improved/delayed with weight loss. Thus, several scientific societies and governments have launched guidelines to reduce body weight and adiposity or, at least, to avoid weight gain. In spite of the abundant literature on the topic, there is still controversy on the relative roles of fat and carbohydrate in the diet on weight gain. Present recommendations to avoid weight gain and obesity are directed to reduce intake of total energy variably and of total fat to <30% of energy, in spite on the lack of evidence of protection against cardiovascular disease (CVD) and mortality. By contrast, both high and low carbohydrate diets are associated with CVD and all-cause mortality in prospective studies, with a safe intake level at ≈50% of energy. Many popular diets with widely different macronutrient composition, including the Mediterranean diet, have been used in obesity; when energy-restricted, all result in similar modest weight loss at 6 months, but the effects are largely lost at 12 months. The Mediterranean diet is a plant-based, high-fat, high-unsaturated fat dietary pattern that has been consistently associated with lower rates on non-communicable diseases and total mortality in prospective studies and with reduced CVD in the PREDIMED trial. For this merits above other diets, this dietary pattern might also be used advantageously for weight loss. The results of the PREDIMED and PREDIMED-Plus randomized controlled trials on adiposity variables in high-risk populations are discussed.

     

Should we recommend low‐fat diets for obesity?

Dietary fat intake has been blamed for the increase in adiposity and has led to a worldwide effort to decrease the amount of fat in the diet. However, the comparative efficacy of this approach is debatable. Whilst short‐term dietary intervention studies show that low‐fat diets lead to weight loss in both healthy and overweight individuals, it is less clear if a reduction in fat intake is more efficacious than other dietary restrictions in the long term. The purpose of this systematic review was to determine the effectiveness of low‐fat diets in achieving sustained weight loss when used for the express purpose of weight loss in obese or overweight people. A comprehensive search identified six studies that fulfilled our criteria for inclusion (randomized controlled trial, participants either overweight or obese, comparison of a low‐fat diet with another type of weight‐reducing diet, follow‐up period that was at least 6 months in duration and inclusion of participants 18 years or older without serious disease). There were a total of 594 participants in the six trials. The duration of the intervention varied from 3 to 18 months with follow‐up from 6 to 18 months. There were no significant differences between low‐fat diets and other weight‐reducing diets in terms of sustained weight loss. Furthermore, the overall weight loss at the 12–18‐month follow‐up in all studies was very small (2–4 kg). In overweight or obese individuals who are dieting for the purpose of weight reduction, low‐fat diets are as efficacious as other weight‐reducing diets for achieving sustained weight loss, but not more so.     

Lifestyle modification for the management of obesity

Several expert panels have recommended that obese individuals attempt to lose 10% of their initial body weight through a combination of diet, physical activity, and behavior therapy (frequently referred to as lifestyle modification). This article reviews the short-and long-term results of lifestyle modification and methods to improve them. Randomized controlled trials were examined that compared different diet and activity interventions for inducing and maintaining weight loss. Studies that compared different methods of providing lifestyle modification, including on-site vs. Internet-based delivery, also were examined. A comprehensive lifestyle modification program was found to induce a loss of approximately 10% of initial weight in 16 to 26 weeks of group or individual treatment, delivered on-site. Comprehensive Internet-based programs induced a loss of approximately half this size. Patients' consumption of portion-controlled diets, including liquid meal replacements, was associated with significantly greater short-term weight loss than was the consumption of isocaloric diets comprised of conventional foods. Factors associated with long-term weight control included continued patient-practitioner contact (whether on-site or by e-mail), high levels of physical activity, and the long-term use of pharmacotherapy combined with lifestyle modification. In summary, lifestyle modification induces clinically significant weight loss that is associated with the prevention or amelioration of cardiovascular risk factors.     

Dietary approaches to reducing body weight.

Diet is one of the cornerstones of a weight loss programme. Although there is little evidence that diet composition plays a clinically important role in the absorption or expenditure of energy, it does appear to play a role in food intake. Diets with a deficit of 500-1000 kcal per day will produce weight losses of between 300 and 1000 g per week, depending on the patient's weight. Formulae for estimating energy intake are provided. Starvation diets with an energy intake below 200 kcal per day are no longer used, but very low-energy diets with an energy intake of between 200 and 800 kcal per day have been used, although there is little to support the use of energy levels below 800 kcal per day. Ad libitum low-fat diets have been reported to produce weight losses that average 1.6 g per day for each 1% reduction in the level of fat. In a meta-analysis, overweight subjects lost 5-7 kg before reaching a new plateau. In normal weight subjects, the loss was only 0.5 kg. A low-fat diet may be of value in helping patients to maintain their weight loss. Higher-protein diets were more effective than low-protein diets in one clinical trial. The type of carbohydrate in the low-fat diet does not appear to influence weight loss. Alcohol, on the other hand, is poorly satiating and may replace fat in oxidative processes, thus enhancing the risk of obesity.     

Managing childhood obesity: when lifestyle change is not enough

The management of childhood obesity is a clinical dilemma. Paediatricians will see those children whose weight is at the severe end of the spectrum with obesity-related co-morbidities and for whom more intensive weight loss therapies may be appropriate. A literature review was performed (January 1995-January 2010) of the roles of pharmacotherapy or bariatric surgery in the management of childhood obesity. Three hundred and eighty-three abstracts were reviewed and 76 full-text articles were requested. Of these, 34 were excluded and a total of 21 pharmacotherapy papers and 22 papers on surgery were reviewed in detail. All studies involved adolescents. Pharmacotherapy: Most studies were small and of short duration, the notable exceptions being two large RCTs of sibutramine and orlistat. Sibutramine led to a mean estimated change in BMI from baseline of -3.1 kg/m(2) vs. -0.3 kg/m(2) for placebo over 12 months. Orlistat was also beneficial with a mean reduction in BMI of 0.55 vs. an increase of 0.31 kg/m(2) in the placebo group at 12 months. Bariatric surgery: Most papers presented clinical observations and there were no randomised controlled trials (RCTs). Robust selection criteria were not used and ideal candidate selection remains unclear. Most papers showed a significant benefit of surgery in severely obese adolescents in the short term but long-term data were sparse. There were a surprisingly large number of papers examining the benefits of intensive weight management in obese adolescents. The study design of many was inadequate and the role of pharmacotherapy or surgery in childhood obesity remains unclear.     

Clinical effectiveness of very‐low‐energy diets in the management of weight loss: a systematic review and meta‐analysis of randomized controlled trials

Guidelines suggest that very‐low‐energy diets (VLEDs) should be used to treat obesity only when rapid weight loss is clinically indicated because of concerns about rapid weight regain. Literature databases were searched from inception to November 2014. Randomized trials were included where the intervention included a VLED and the comparator was no intervention or an intervention that could be given in a general medical setting in adults that were overweight. Two reviewers characterized the population, intervention, control groups, outcomes and appraised quality. The primary outcome was weight change at 12 months from baseline. Compared with a behavioural programme alone, VLEDs combined with a behavioural programme achieved ?3.9 kg [95% confidence interval (CI) ?6.7 to ?1.1] at 1 year. The difference at 24 months was ?1.4 kg (95%CI ?2.6 to ?0.2) and at 38–60 months was ?1.3 kg (95%CI ?2.9 to 0.2). Nineteen per cent of the VLED group discontinued treatment prematurely compared with 20% of the comparator groups, relative risk 0.96 (0.56 to 1.66). One serious adverse event, hospitalization with cholecystitis, was reported in the VLED group and none in the comparator group. Very‐low‐energy diets with behavioural programmes achieve greater long‐term weight loss than behavioural programmes alone, appear tolerable and lead to few adverse events suggesting they could be more widely used than current guidelines suggest.     

A systematic review and meta‐analysis of the effectiveness of meal replacements for weight loss

Meal replacements (MR) are generally not recommended in clinical guidelines for the management of obesity. The aim of this review is to provide an up‐to‐date systematic evaluation of the effect of weight loss interventions incorporating MR compared with alternative interventions on weight change at 1 year in adults with overweight or obesity. Six electronic databases were searched from inception to the end of August 2018 for randomized controlled trials comparing the effect of MR with interventions that did not include MR on weight at 1 year. We excluded studies using diets providing <3347 kJ/(800 kcal)/day and those which used total diet replacement (TDR) from this review. Risk of bias was assessed using the Cochrane risk of bias tool. Twenty‐three studies with 7884 adult participants were included. Six out of 23 studies were judged at low risk of bias across all domains, and 5/23 studies were judged at high risk of bias in at least one domain. Studies with similar intervention and comparators were grouped into five comparisons for analysis. Mean weight change at 1 year favoured the MR group relative to the control group in each comparison. In those comparisons where we conducted meta‐analysis, in people assigned to a diet incorporating MR, mean difference was ?1.44 kg (?2.48 to ?0.39 kg; I² = 38%) compared with alternative kinds of diets. In those assigned to a MR diet along with support, mean difference was ?2.22 kg (?3.99 to ?0.45, I² = 81%) compared with other diets with support and ?3.87 kg (?7.34 to ?0.40; I² = 60%) compared with other kinds of diet without support. In those assigned a MR diet with an enhanced level of support, mean difference was ?6.13 kg (?7.35 to ?4.91, I² = 19%) compared with alternative diets and regular support. Programmes incorporating meal replacements led to greater weight loss at 1 year than comparator weight loss programmes and should be considered as a valid option for management of overweight and obesity in community and health care settings.     

Will reducing sugar‐sweetened beverage consumption reduce obesity? Evidence supporting conjecture is strong,but evidence when testing effect is weak

We provide arguments to the debate question and update a previous meta‐analysis with recently published studies on effects of sugar‐sweetened beverages (SSBs) on body weight/composition indices (BWIs). We abstracted data from randomized controlled trials examining effects of consumption of SSBs on BWIs. Six new studies met these criteria: (i) human trials, (ii) ≥ 3 weeks duration, (iii) random assignment to conditions differing only in consumption of SSBs and (iv) including a BWI outcome. Updated meta‐analysis of a total of seven studies that added SSBs to persons’ diets showed dose‐dependent increases in weight. Updated meta‐analysis of eight studies attempting to reduce SSB consumption showed an equivocal effect on BWIs in all randomized subjects. When limited to subjects overweight at baseline, meta‐analysis showed a significant effect of roughly 0.25 standard deviations (more weight loss/less weight gain) relative to controls. Evidence to date is equivocal in showing that decreasing SSB consumption will reduce the prevalence of obesity. Although new evidence suggests that an effect may yet be demonstrable in some populations, the integrated effect size estimate remains very small and of equivocal statistical significance. Problems in this research area and suggestions for future research are highlighted.     

Low-fat, high-carbohydrate (low-glycaemic index) diet induces weight loss and preserves lean body mass in obese healthy subjects: results of a 24-week study

BACKGROUND: The traditional treatment for obesity which is based on a reduced caloric diet has only been partially successful. Contributing factors are not only a poor long-term dietary adherence but also a significant loss of lean body mass and subsequent reduction in energy expenditure. Both low-fat, high-carbohydrate diets and diets using low-glycaemic index (GI) foods are capable of inducing modest weight loss without specific caloric restriction. The purpose of this study was to investigate the feasibility and medium-term effect of a low-fat diet with high (low GI) carbohydrates on weight loss, body composition changes and dietary compliance. METHODS: Obese patients were recruited from two obesity outpatient clinics. Subjects were given advise by a dietician, then they attended biweekly for 1-hour group meetings. Bodyweight and body composition were measured at baseline and after 24 weeks. RESULTS: One hundred and nine (91%) patients completed the study; after 24 weeks the average weight loss was 8.9 kg (98.6 vs. 89.7 kg; p < or = 0.0001). There was a significant 15% decrease in fat mass (42.5 vs. 36.4 kg; p < or = 0.0001) and a decrease in lean body mass of 5% (56.1 vs. 53.3 kg; p < or = 0.0001). DISCUSSION: In this 6-month study, a low-fat, low-GI diet led to a significant reduction of fat mass; adherence to the diet was very good. Our results suggest that such a diet is feasible and should be evaluated in randomized controlled trials.