Very low-energy diets for weight loss in adults: A review

Eating Disorders In weight-related Therapy (EDIT) Collaboration: rationale and study design

The cornerstone of obesity treatment is behavioural weight management, resulting in significant improvements in cardio-metabolic and psychosocial health. However, there is ongoing concern that dietary interventions used for weight management may precipitate the development of eating disorders. Systematic reviews demonstrate that, while for most participants medically supervised obesity treatment improves risk scores related to eating disorders, a subset of people who undergo obesity treatment may have poor outcomes for eating disorders. This review summarises the background and rationale for the formation of the Eating Disorders In weight-related Therapy (EDIT) Collaboration. The EDIT Collaboration will explore the complex risk factor interactions that precede changes to eating disorder risk following weight management. In this review, we also outline the programme of work and design of studies for the EDIT Collaboration, including expected knowledge gains. The EDIT studies explore risk factors and the interactions between them using individual-level data from international weight management trials. Combining all available data on eating disorder risk from weight management trials will allow sufficient sample size to interrogate our hypothesis: that individuals undertaking weight management interventions will vary in their eating disorder risk profile, on the basis of personal characteristics and intervention strategies available to them. The collaboration includes the integration of health consumers in project development and translation. An important knowledge gain from this project is a comprehensive understanding of the impact of weight management interventions on eating disorder risk.

Alternate day fasting on subjective feelings of appetite and body weight for adults with overweight or obesity: a systematic review

Alternate day fasting (ADF) with consumption of calories up to 25 % of the daily energy intake on fast days is one of the most used intermittent fasting regimens and promoted as a promising, alternative approach for treating obesity. Feelings of appetite are critical for adherence to dietary approaches, and therefore the success of dietary interventions. This systematic review aimed to assess the effects of a minimum of 8 weeks of ADF on subjective feelings of appetite and body weight for adults with overweight and obesity. We conducted the review in accordance with the Cochrane guidelines, including systematic searches in four databases. Because of the high level of clinical and methodological heterogeneity, a narrative approach was used to synthesise the results. Eight studies with a total of 456 participants met the eligibility criteria: three randomised controlled trials and five uncontrolled before-after studies. Seven of the studies had high risk of bias. Feelings of appetite were assessed by hunger in eight studies, fullness in seven studies, satisfaction in four studies and desire to eat in one study. All the studies assessed weight loss. The certainty of the evidence was rated low or very low for all outcomes, thus no firm conclusions can be drawn about the potential benefits of ADF on subjective feelings of appetite and body weight. Despite the high interest in ADF, good quality evidence is still needed to determine its effectiveness and if offered in clinical practice, ADF should be offered cautiously while concomitantly evaluated.

Body Protein Sparing in Hibernators: A Source for Biomedical Innovation

Proteins are not only the major structural components of living cells but also ensure essential physiological functions within the organism. Any change in protein abundance and/or structure is at risk for the proper body functioning and/or survival of organisms. Death following starvation is attributed to a loss of about half of total body proteins, and body protein loss induced by muscle disuse is responsible for major metabolic disorders in immobilized patients, and sedentary or elderly people. Basic knowledge of the molecular and cellular mechanisms that control proteostasis is continuously growing. Yet, finding and developing efficient treatments to limit body/muscle protein loss in humans remain a medical challenge, physical exercise and nutritional programs managing to only partially compensate for it. This is notably a major challenge for the treatment of obesity, where therapies should promote fat loss while preserving body proteins. In this context, hibernating species preserve their lean body mass, including muscles, despite total physical inactivity and low energy consumption during torpor, a state of drastic reduction in metabolic rate associated with a more or less pronounced hypothermia. The present review introduces metabolic, physiological, and behavioral adaptations, e.g., energetics, body temperature, and nutrition, of the torpor or hibernation phenotype from small to large mammals. Hibernating strategies could be linked to allometry aspects, the need for periodic rewarming from torpor, and/or the ability of animals to fast for more or less time, thus determining the capacity of individuals to save proteins. Both fat- and food-storing hibernators rely mostly on their body fat reserves during the torpid state, while minimizing body protein utilization. A number of them may also replenish lost proteins during arousals by consuming food. The review takes stock of the physiological, molecular, and cellular mechanisms that promote body protein and muscle sparing during the inactive state of hibernation. Finally, the review outlines how the detailed understanding of these mechanisms at play in various hibernators is expected to provide innovative solutions to fight human muscle atrophy, to better help the management of obese patients, or to improve the ex vivo preservation of organs.

Efficacy of low- and very-low-energy diets in people with type 2 diabetes mellitus: A systematic review and meta-analysis of interventional studies

AIMS

To review systematically and quantify the weight loss achieved through low- (LEDs) and very-low-energy diets (VLEDs) in people with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

Studies reporting the effects of diet-only interventions of up to 1600 kcal/d in people with T2DM were searched in MEDLINE, EMBASE and CINAHL up to July 2018. Changes in the primary (body weight and body mass index [BMI]) and secondary outcomes (glycated haemoglobin, blood lipids) according to energy restriction and duration of diet were modelled using restricted cubic splines.

RESULTS

Forty-four studies (3817 participants) were included. The overall quality of the evidence was moderate and limited to short-term interventions up to 4 months. Baseline mean weight and BMI were 92.1 kg and 36.6 kg/m² . VLEDs of 400 kcal/d led to 5.4% weight loss at 2 weeks, increasing to 17.9% at 3 months. More modest reductions of 7.3% were observed on LEDs of 1200 kcal/d and 2.0% on 1600 kcal/d after 3 months. No clear patterns emerged for secondary outcomes. Publication bias was significant for primary outcomes.

CONCLUSIONS

Through modelling, we were able to describe effective dietary deficit strategies to achieve weight reduction up to 4 months in people with T2DM. High-quality studies are required to further support clinical practice with evidence-based dietary interventions.

Efficacy of very low-energy diet programs for weight loss: A systematic review with meta-analysis of intervention studies in children and adolescents with obesity

The objective of this review was to evaluate the efficacy and safety of very low-energy diet (VLED) programs for weight loss in children and adolescents with obesity. Six electronic databases were searched identifying 24 eligible studies (16 pre-post studies, four nonrandomized trials, two randomized controlled trials [RCTs], and two chart reviews) published up to October 2018. Studies were in English, implemented a VLED (≤3360 kJF/day [≤800 kcal/day] or <50% estimated energy requirements) in 5- to 18-year-olds with obesity, and reported at least one weight-related outcome. Weight-related outcomes significantly improved postintervention in all studies. Meta-analysis of 20 studies indicated a mean 10.1 kg (95% confidence interval [CI], 8.7-11.4 kg, P < 0.001; I²  = 92.3%) weight loss following interventions lasting 3 to 20 weeks. Moderator analysis indicated greater weight loss in adolescent-only studies (10-18 years) and formulated meal replacement interventions and inpatient settings. Meta-analysis of seven studies reporting weight at follow-up (5-14.5 months from baseline) indicated 5.3 kg mean weight loss (CI, 2.5-8.0 kg, P < 0.001; I²  = 50.6%). Details of adverse events were limited. VLED programs are effective for treating children and adolescents with obesity. However, conclusions on their safety cannot be drawn from the existing literature at this time. Future studies should include long-term follow-up with ongoing support and comprehensive monitoring of all adverse events.

Comparison of Very Low Energy Diet Products Available in Australia and How to Tailor Them to Optimise Protein Content for Younger and Older Adult Men and Women

Very low energy diets (VLED) are efficacious in inducing rapid weight loss but may not contain adequate macronutrients or micronutrients for individuals with varying nutritional requirements. Adequate protein intake during weight loss appears particularly important to help preserve fat free mass and control appetite, and low energy and carbohydrate content also contributes to appetite control. Therefore, the purpose of this study was to compare the nutritional content (with a focus on protein), nutritional adequacy and cost of all commercially-available VLED brands in Australia. Nutritional content and cost were extracted and compared between brands and to the Recommended Dietary Intake (RDI) or adequate intake (AI) of macronutrients and micronutrients for men and women aged 19-70 years or >70 years. There was wide variability in the nutritional content, nutritional adequacy and cost of VLED brands. Most notably, even brands with the highest daily protein content, based on consuming three products/day (KicStart™ and Optislim(®), ~60 g/day), only met estimated protein requirements of the smallest and youngest women for whom a VLED would be indicated. Considering multiple options to optimise protein content, we propose that adding pure powdered protein is the most suitable option because it minimizes additional energy, carbohydrate and cost of VLEDs.

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.

Stable isotope analysis of dietary arginine accrual and disposal efficiency in male rats fed diets with different protein content

The administration of diets with different protein/energy ratios induce variable but distinctive responses in rats; an excessive protein content tends to decrease fat accumulation, but reversion of this ratio tends to increase adipose tissue mass.

Does severe dietary energy restriction increase binge eating in overweight or obese individuals? A systematic review

Severe dietary energy restriction is often used for overweight or obese individuals to achieve rapid weight loss and related health improvements. However, the extent of putative adverse effects on eating behaviour is unknown. We thus systematically searched seven databases for studies that assessed binge eating before and after severe dietary energy restriction (low or very low energy diets) in overweight or obese individuals. Fifteen clinically supervised interventions from 10 publications (nine of which involved only women) were included. Among individuals with clinically relevant pre-treatment binge eating disorder, severe dietary energy restriction significantly decreased binge eating in all four interventions involving this population, at least during the weight loss programme. In contrast, no consistent association between severe dietary energy restriction and the onset of bingeing was found in 11 interventions involving individuals without pre-treatment binge eating disorder, with four such interventions showing significant increases, two showing no change, and five showing significant decreases in binge eating. We conclude that clinically supervised severe dietary energy restriction appears safe and beneficial for overweight or obese individuals with pre-treatment binge eating disorder, and does not necessarily trigger binge eating in those without binge eating disorder.

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 SHED-IT weight loss maintenance trial protocol: A randomised controlled trial of a weight loss maintenance program for overweight and obese men

Despite short-term efficacy, many weight loss studies demonstrate poor long-term results and have difficulty recruiting men. Cost-effective treatments that help men achieve long-term weight loss are required. Using a two-phase, assessor-blinded, parallel-group randomised controlled trial design this study will test the effectiveness and cost-effectiveness of a male-only weight loss maintenance intervention. In Phase I (3 months) 209 men received the SHED-IT Weight Loss Program. In Phase II (12 months) 92 men who lost 4 kg or more were randomised to either (i) a maintenance group who received the 6-month, gender-tailored SHED-IT Weight Loss Maintenance Program, which included no face-to-face contact (n = 47), or (ii) a self-help control group (n = 45). Randomisation was stratified by weight loss (4 kg-7.4 kg, ≥7.5 kg) and BMI (<30 kg/m(2), ≥30 kg/m(2)). Assessments occurred at 'study entry' (start of Phase I), 'baseline' (start of Phase II), '6 months' (post-test) and will occur at '12 months' (follow-up; primary endpoint). The primary outcome is weight change in Phase II (i.e. from 'baseline' at 12 months after randomization). Secondary outcomes include waist circumference (umbilicus and narrowest), blood pressure, body composition, objectively measured physical activity, sedentary time, portion size, dietary intake, quality of life, depressive symptoms, and behavioural cognitions. Costing data will be collected for cost-effectiveness analysis. Generalised linear mixed models (intention-to-treat) will assess outcomes for treatment (maintenance vs. control), time (baseline, 6-month and 12-month) and the treatment-by-time interaction. This will be the first study to evaluate a male-only, gender-targeted weight loss maintenance program. Results will provide evidence regarding feasible and theoretically-driven obesity treatments for men with potential for long-term impact and widespread dissemination.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (ACTRN12612000749808).