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Effect of planned pauses versus continuous energy restriction on weight loss and attrition: a systematic review.
Wren, GM, Koutoukidis, DA, Scragg, J, Tsompanaki, E, Hobson, A, Jebb, SA
Obesity (Silver Spring, Md.). 2024;(3):454-465
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OBJECTIVE The objective of this study was to investigate whether pausing a weight loss program for a defined period of time could enhance weight loss and reduce attrition. METHODS Five databases and two trial registries were searched from inception to July 2023. Randomized-controlled trials of adults with overweight and/or obesity were included if they compared planned-pause interventions with continuous energy restriction (CER), usual care, or a minimal intervention. To be included, the weight loss intervention must have incorporated a pause of at least 1 week. Pooled mean differences for weight change and risk ratios for attrition were calculated using random-effects meta-analyses. RESULTS Nine intervention arms (N = 796 participants, 77% female) were included. Pooled results did not detect a significant difference in weight change between planned pauses and CER interventions at the end of the active intervention at a median 26 weeks (planned pauses vs. CER mean: -7.09 vs. -7.0 kg; mean difference: -0.09 kg; 95% CI: -1.10 to 0.93) or at final follow-up at a median 52 weeks (planned pauses vs. CER mean: -6.91 vs. -6.19 kg; mean difference: -0.72 kg; 95% CI: -2.92 to 1.48). There was no difference in attrition between planned pauses and CER interventions at the end of the active intervention (risk ratio: 1.20, 95% CI: 0.82 to 1.75) or at final follow-up (risk ratio: 1.04, 95% CI: 0.89 to 1.22). CONCLUSIONS Planned pauses were consistently found to be no more or less effective than CER for weight loss or attrition.
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REduced-Carbohydrate intervention for managing Obesity and Reduction of gestational Diabetes (RECORD): A randomized controlled feasibility trial.
Michalopoulou, M, Jebb, SA, MacKillop, LH, Dyson, P, Hirst, JE, Zhu, S, Wire, A, Astbury, NM
Diabetes, obesity & metabolism. 2024;(4):1407-1420
Abstract
AIM: To test the feasibility and acceptability of a reduced-carbohydrate dietary program, intended to reduce the risk of gestational diabetes. MATERIALS AND METHODS Fifty-one pregnant women at <20 weeks' gestation, with body mass index ≥30 kg/m2 , and a normal baseline oral glucose tolerance test (OGTT), were randomized 2:1 to an intervention or control group and followed-up until delivery. The dietary intervention aimed at providing 130-150 g carbohydrate/day. Feasibility outcomes assessed at 24-28 weeks' gestation, included adoption of the reduced-carbohydrate diet by the intervention group, and retention of all participants, assessed by completion of a second OGTT. Changes in glycemia, weight gain and dietary intake, and the maternal and neonatal outcomes were also assessed. Participants were interviewed about their experience of the intervention and the study. RESULTS Forty-nine of 51 participants attended the follow-up OGTT, a retention rate of 96% (95% confidence interval [CI] 86.8%-98.9%). In the intervention group, carbohydrate intake at follow-up was 190.4 (95% CI 162.5-215.6) g/day, a reduction of -24.6 (95% CI -51.5-2.4) g/day from baseline. Potentially favourable effects of the intervention on glucose control, weight gain and blood pressure were observed, but the study was not powered to detect significant differences in these. Participants found the intervention acceptable, and were content with the study processes, but some reported barriers to sustained adherence, mainly pertaining to competing priorities. CONCLUSIONS Retention was high, suggesting the study processes are feasible, but the carbohydrate reduction in the intervention group was small, and did not meet progression criteria, limiting the likelihood of achieving the desired goal to prevent gestational diabetes. TRIAL REGISTRATION NUMBER ISRCTN16235884.
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Evaluating the efficacy and mechanisms of a ketogenic diet as adjunctive treatment for people with treatment-resistant depression: A protocol for a randomised controlled trial.
Gao, M, Kirk, M, Lash, E, Knight, H, Michalopoulou, M, Guess, N, Browning, M, Weich, S, Burnet, P, Jebb, SA, et al
Journal of psychiatric research. 2024;:230-236
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BACKGROUND One-third of people with depression do not respond to antidepressants, and, after two adequate courses of antidepressants, are classified as having treatment-resistant depression (TRD). Some case reports suggest that ketogenic diets (KDs) may improve some mental illnesses, and preclinical data indicate that KDs can influence brain reward signalling, anhedonia, cortisol, and gut microbiome which are associated with depression. To date, no trials have examined the clinical effect of a KD on TRD. METHODS This is a proof-of-concept randomised controlled trial to investigate the efficacy of a six-week programme of weekly dietitian counselling plus provision of KD meals, compared with an intervention involving similar dietetic contact time and promoting a healthy diet with increased vegetable consumption and reduction in saturated fat, plus food vouchers to purchase healthier items. At 12 weeks we will assess whether participants have continued to follow the assigned diet. The primary outcome is the difference between groups in the change in Patient Health Questionnaire-9 (PHQ-9) score from baseline to 6 weeks. PHQ-9 will be measured at weeks 2, 4, 6 and 12. The secondary outcomes are the differences between groups in the change in remission of depression, change in anxiety score, functioning ability, quality of life, cognitive performance, reward sensitivity, and anhedonia from baseline to 6 and 12 weeks. We will also assess whether changes in reward sensitivity, anhedonia, cortisol awakening response and gut microbiome may explain any changes in depression severity. DISCUSSION This study will test whether a ketogenic diet is an effective intervention to reduce the severity of depression, anxiety and improve quality of life and functioning ability for people with treatment-resistant depression.
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Participants' perspectives of being recruited into a randomised trial of a weight loss intervention before colorectal cancer surgery: a qualitative interview study.
Talbot, A, Jebb, SA, Foster, C, Realpe, AX, Wheatstone, P, Buczacki, S, Koutoukidis, DA
BMC cancer. 2024;(1):802
Abstract
BACKGROUND The period between cancer diagnosis and surgery presents an opportunity for trials to assess the feasibility of behaviour change interventions. However, this can be a worrying time for patients and may hinder recruitment. We describe the perspectives of patients with excess weight awaiting colorectal cancer surgery about their recruitment into a randomised trial of a prehabilitation weight loss intervention. METHODS We interviewed the first 26 participants from the 8 recruitment sites across England in the 'CARE' feasibility trial. Participants were randomised into either usual care (n = 13) or a low-energy nutritionally-replete total diet replacement programme with weekly remote behavioural support by a dietitian (n = 13). The semi-structured interviews occurred shortly after recruitment and the questions focused on participants' recollections of being recruited into the trial. We analysed data rapidly and then used a mind-mapping technique to develop descriptive themes. Themes were agreed by all co-authors, including a person with lived-experience of colorectal surgery. RESULTS Participants had a mean body mass index (± SD) of 38 kg/m2 (± 6), age of 50 years (± 12), and 42% were female. People who participated in the trial were motivated by the offer of structured weight loss support that could potentially help them improve their surgical outcomes. However, participants also had concerns around the potential unpalatability of the intervention diet and side effects. Positive attitudes of clinicians towards the trial facilitated recruitment but participants were disappointed when they were randomised to usual care due to clinical teams' overemphasis on the benefits of losing weight. CONCLUSIONS Patients were motivated to take part by the prospect of improved surgical outcomes. However, the strong preference to be allocated to the intervention suggests that balanced communication of equipoise is crucial to minimise disappointment from randomisation to usual care and differential dropout from the trial. CLINICAL TRIAL REGISTRATION ISRCTN39207707, Registration date 13/03/2023.
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Identifying Preferred Features of Weight Loss Programs for Adults With or at Risk of Type 2 Diabetes: A Discrete Choice Experiment With 3,960 Adults in the U.K.
Buckell, J, Mitchell, CA, Fryer, K, Newbert, C, Brennan, A, Joyce, J, Jebb, SA, Aveyard, P, Guess, N, Morris, E
Diabetes care. 2024;(4):739-746
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OBJECTIVE To understand preferences for features of weight loss programs among adults with or at risk of type 2 diabetes in the U.K. RESEARCH DESIGN AND METHODS We conducted a discrete choice experiment with 3,960 U.K. adults living with overweight (n = 675 with type 2 diabetes). Preferences for seven characteristics of weight loss programs were analyzed. Simulations from choice models using the experimental data predicted uptake of available weight loss programs. Patient groups comprising those who have experience with weight loss programs, including from minority communities, informed the experimental design. RESULTS Preferences did not differ between individuals with and without type 2 diabetes. Preferences were strongest for type of diet. Healthy eating was most preferred relative to total diet replacement (odds ratio [OR] 2.24; 95% CI 2.04-2.44). Individual interventions were more popular than group interventions (OR 1.40; 95% CI 1.34-1.47). Participants preferred programs offering weight loss of 10-15 kg (OR 1.37; 95% CI 1.28-1.47) to those offering loss of 2-4 kg. Online content was preferred over in-person contact (OR 1.24; 95% CI 1.18-1.30). There were few differences in preferences by gender or ethnicity, although weight loss was more important to women than to men, and individuals from ethnic minority populations identified more with programs where others shared their characteristics. Modeling suggested that tailoring programs to individual preferences could increase participation by ∼17 percentage points (68% in relative terms). CONCLUSIONS Offering a range of weight loss programs targeting the preferred attributes of different patient groups could potentially encourage more people to participate in weight loss programs and support those living with overweight to reduce their weight.
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The impact of price promotions on confectionery and snacks on the energy content of shopping baskets: A randomised controlled trial in an experimental online supermarket.
Luick, M, Pechey, R, Harmer, G, Bandy, L, Jebb, SA, Piernas, C
Appetite. 2023;:106539
Abstract
Overconsumption of foods high in fat, sugars, and salt (HFSS) poses a significant risk to health. The government in England has passed legislation that would limit some price promotions of HFSS foods within supermarkets, but evidence regarding likely impacts of these policies, especially in online settings, is limited. This study aimed to determine whether there were any differences in the energy and nutrient content of shopping baskets after removing promotions on HFSS foods in an online experimental supermarket. UK adults (n = 511) were asked to select food from four categories with a £10 budget in an online experimental supermarket: confectionery; biscuits and crackers; crisps, nuts and snacking fruit; cakes and tarts. They were randomly allocated to one of two trial arms: (1) promotions present (matched to promotion frequency seen in a major UK retailer) (n = 257), or (2) all promotions removed from all products within the target food categories (n = 254). The primary outcome analysis used linear regression to compare total energy (kcal) of items placed in shopping baskets when promotions were present vs. absent, while secondary analyses investigated differences in nutrients and energy purchased from individual food categories. Mean energy in food selected without promotions was 5156 kcal per basket (SD 1620), compared to 5536 kcal (SD 1819) with promotions, a difference of -552kcal (95%CIs: -866, -238), equivalent to 10%. There were no significant differences in energy purchased for any individual category between groups. No evidence was found of other changes in nutritional composition of baskets or of significant interactions between the impact of promotions and participant characteristics (gender, age, ethnicity) on energy purchased. Removing promotions on HFSS foods resulted in significantly less total energy selected in an online experimental supermarket study.
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Dietary Approaches to the Management Of type 2 Diabetes (DIAMOND) in primary care: A protocol for a cluster randomised trial.
Scragg, J, Morris, E, Wane, S, Noreik, M, Jerome, D, Yu, LM, Galal, U, Dyson, P, Tan, GD, Fox, R, et al
Contemporary clinical trials. 2023;:107199
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INTRODUCTION There is strong evidence that type 2 diabetes (T2D) remission can be achieved by adopting a low-energy diet achieved through total dietary replacement products. There is promising evidence that low-carbohydrate diets can achieve remission of T2D. The Dietary Approaches to the Management of type 2 Diabetes (DIAMOND) programme combines both approaches in a behaviourally informed low-energy, low-carbohydrate diet for people with T2D, delivered by nurses in primary care. This trial compares the effectiveness of the DIAMOND programme to usual care in inducing remission of T2D and in reducing risk of cardiovascular disease. METHODS AND ANALYSIS We aim to recruit 508 people in 56 practices with T2D diagnosed within 6 years, who are demographically representative of the UK population. We will allocate general practices, based on ethnicity and socioeconomic status, to provide usual care for diabetes or offer the DIAMOND programme. Participants in practices offering DIAMOND will see the nurse seven times over 6 months. At baseline, 6 months, and 1 year we will measure weight, blood pressure, HbA1c, lipid profile and risk of fatty liver disease. The primary outcome is diabetes remission at 1 year, defined as HbA1c < 48 mmol/mol and off glucose-lowering medication for at least 6 months. Thereafter, we will assess whether people resume treatment for diabetes and the incidence of microvascular and macrovascular disease through the National Diabetes Audit. Data will be analysed using mixed-effects generalised linear models. This study has been approved by the National Health Service Health Research Authority Research Ethics Committee (Ref: 22/EM/0074). TRIAL REGISTRATION NUMBER ISRCTN46961767.
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A systematic review of economic evaluations of interventions targeting childhood overweight and obesity.
Onyimadu, O, Violato, M, Astbury, NM, Hüls, H, Heath, L, Shipley, A, Taylor, H, Wilkins, LE, Abhari, RE, Jebb, SA, et al
Obesity reviews : an official journal of the International Association for the Study of Obesity. 2023;(9):e13597
Abstract
This systematic review critically appraised and synthesized evidence from economic evaluations of interventions targeting childhood excess weight. We conducted systematic searches in 11 databases from inception to April 19, 2023. Studies were eligible if they evaluated interventions targeting children up to 18 years and the study intervention(s) targeted childhood excess weight or sought to improve diet or physical activity, regardless of the type of economic evaluation or the underpinning study design. We synthesized evidence using narrative synthesis methods. One-hundred fifty-one studies met the eligibility criteria and were classified into three groups based on the intervention approach: prevention-only (13 studies), prevention and treatment (100 studies), and treatment-only (38 studies). The predominant setting and study design differed considerably between the three groups of studies. However, compared with usual care, most interventions were deemed cost-effective. The study participants' ages, sex, and socioeconomic status were crucial to intervention cost-effectiveness. Interventions whose effects were projected beyond childhood, such as bariatric surgery, lower protein infant formula, and home-based general practitioner consultations, tended to be cost-effective. However, cost-effectiveness was sensitive to the assumptions underlying the persistence and intensity of such effects. Our findings can inform future recommendations on the conduct of economic evaluations of interventions targeting childhood overweight and obesity, as well as practice and policy recommendations.
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Weight regain and mental health outcomes following behavioural weight management programmes: A systematic review with meta-analyses.
Theodoulou, A, Hartmann-Boyce, J, Gorenberg, J, Oke, JL, Butler, AR, Bastounis, A, Jebb, SA, Aveyard, P
Clinical obesity. 2023;(3):e12575
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Behavioural weight management programmes (BWMPs) lead to weight loss but subsequent weight regain may harm mental health outcomes. We searched for randomised trials of BWMPs in adults with overweight/obesity with follow-up ≥12 months from baseline that measured weight change both at and after programme-end. We included only studies reporting mental health at or after programme-end. We meta-analysed changes in various mental health outcomes using a random-effects model by nature of the comparator group and by time since programme end. Subgroup analysis explored heterogeneity. We used mixed models and meta-regression to analyse the association between change in weight and change in depression and/or anxiety over time, with higher scores indicating greater depression and/or anxiety. We included 47 studies. When comparing BWMPs (diet and/or exercise) to control, most estimates included the possibility of no difference, but pooled estimates for psychological wellbeing, self-esteem and mental-health composite scores at programme-end, anxiety at 1-6 months, and depression at 7-12 months after programme-end suggested improvements in intervention arms relative to control, with 95% CIs excluding no difference. Pooled estimates found no evidence that BWMPs harmed mental health at programme end or beyond. Mental health composite scores at programme-end favoured diet and exercise interventions over diet alone, with 95% CIs excluding no difference. All other measures and timepoints included the possibility of no difference or could not be meta-analysed due to high heterogeneity or a paucity of data. Mixed models and meta-regression of the association between change in depression and/or anxiety scores over time, and change in weight, were inconclusive. Despite weight regain after BWMPs, our meta-analyses found no evidence of mental health harm and some evidence that BWMPs may improve some dimensions of mental health at and after programme-end.
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Use of Cognitive and Behavioral Strategies During a Weight Loss Program: A Secondary Analysis of the Doctor Referral of Overweight People to Low-Energy Total Diet Replacement Treatment (DROPLET) Trial.
Henry, JA, Astbury, NM, Hartmann-Boyce, J, Koshiaris, C, Jebb, SA
Journal of the Academy of Nutrition and Dietetics. 2023;(10):1417-1428.e17
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BACKGROUND Achieving a sustained energy deficit is essential for weight loss, but the cognitive and behavioral strategies that support this goal are unclear. OBJECTIVE The goal of this study was to investigate the number and type of cognitive and behavioral strategies used by participants who were enrolled in a 1-year weight loss trial and to explore associations between strategies and magnitude of weight loss at 3 months and 1 year. DESIGN The study is a secondary post-hoc exploratory analysis of data collected as part of the Doctor Referral of Overweight People to Low-Energy total diet replacement Treatment (DROPLET), a randomized controlled trial conducted in general practices in England, United Kingdom, between January 2016 and August 2017. PARTICIPANTS/SETTING This study involved 164 participants from both intervention and control groups of the DROPLET trial who completed the Oxford Food and Behaviours (OxFAB) questionnaire to assess the use of 115 strategies grouped into 21 domains used to manage their weight. INTERVENTIONS Participants were randomized to either a behavioral weight loss program involving 8 weeks total diet replacement (TDR) and 4 weeks of food reintroduction or a program delivered by a medical practice nurse over a 3-month period (usual care [UC]). MAIN OUTCOME MEASURES Weight was objectively measured at baseline, 3 months, and 1 year. Cognitive and behavioral strategies used to support weight loss were assessed using the OxFAB questionnaire at 3 months. STATISTICAL ANALYSIS PERFORMED Exploratory factor analysis was used to generate data-driven patterns of strategy use, and a linear mixed-effects model was used to examine associations between use of these patterns and weight change. RESULTS No evidence was found of a difference in the number of strategies (mean difference, 2.41; 95% confidence interval [CI], -0.83, 5.65) or the number of domains used (mean difference, -0.23; 95% CI, -0.69, 0.23) between the TDR group and the UC group. The number of strategies was not associated with weight loss at either 3 months (-0.02 kg; 95% CI, -0.11, 0.06) or 1 year (-0.05 kg; 95% CI, -0.14, 0.02). Similarly, the number of domains used was not associated with weight loss at 3 months (-0.02 kg; 95% CI, -0.53, 0.49) or 1 year (-0.07 kg; 95% CI, -0.60, 0.46). Factor analysis identified four coherent patterns of strategy use, identified as Physical Activity, Motivation, Planned Eating, and Food Purchasing patterns. Greater use of strategies in the Food Purchasing (-2.6 kg; 95% CI, -4.42, -0.71) and Planned Eating patterns (-3.20 kg; 95% CI, -4.94, -1.46) was associated with greater weight loss at 1 year. CONCLUSIONS The number of cognitive and behavioral strategies or domains used does not appear to influence weight loss, but the types of strategy appear of greater importance. Supporting people to adopt strategies linked to planned eating and food purchasing may aid long-term weight loss.
