Long Term Weight Loss Diets and Obesity Indices: Results of a Network Meta-Analysis.

Jana Jabbour, Yasmin Rihawi, Assem M Khamis, Layal Ghamlouche, Bayan Tabban, Gloria Safadi, Nour Hammad, Ruba Hadla, Marwa Zeidan, Dana Andari, Riwa Nour Azar, Nadine Nasser, Marlene Chakhtoura

Journal: Frontiers in nutrition 2022;9():821096

PMID: 35479754

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Plain Language Summary

Obesity is associated with a decreased lifetime expectancy of 5–20 years, depending on the severity and the presence of comorbidities. Diet therapy remains one of the cornerstones of the multi-disciplinary approach to weight management. The aim of this study was to evaluate the association of long-term dietary interventions, categorised using the Acceptable Macronutrient Distribution Ranges, with changes in weight parameters. This study is a systematic review and network meta-analysis of fifty studies. Results indicate that compared with the usual diet, all dietary interventions allow a sustained modest weight loss during the follow-up of 12 months and beyond. Diets did not differ among each other, with the exception of the high-fat low-carbohydrate diet that was slightly better than the low-carbohydrate, low-fat, and moderate macronutrients diet, with a larger weight loss (of 0.8 kg) and body mass index loss (0.4 kg/m2 ). Authors conclude that even though their findings apply to the general population of patients with overweight/obesity, the long-term impact of dietary approaches on patients with chronic diseases should be further investigated.

Abstract

BACKGROUND

Scientists have been investigating efficient interventions to prevent and manage obesity. This network meta-analysis (NMA) compared the effect of different diets [moderate macronutrients (MMs), low fat/high carbohydrate (LFHC), high fat/low carbohydrate (HFLC), and usual diet (UD)] on weight, body mass index (BMI), and waist circumference (WC) changes at ≥12 months.

METHODS

We searched Medline, Embase, PubMed databases, and the Cochrane Library. We systematically assessed randomized controlled trials (RCTs) evaluating dietary interventions on adults (mean BMI ≥ 25 kg/m) receiving active dietary counseling for ≥12 months. We pooled the data using a random-effect NMA. We assessed the quality of the included RCTs using the Cochrane risk of bias (ROB) tool.

RESULTS

We included 36 trials, 14 of which compared HFLC with MM diets. Compared with UD, all diets were associated with a significant weight loss (WL) at ≥12 months, HFLC [mean difference in kg (95% ): -5.5 (-7.6; -3.4)], LFHC [-5.0 (-7.1; -2.9)] and MM [-4.7 (-6.8; -2.7)]. HFLC, compared with MM diet, was associated with a slightly higher WL (of -0.77 kg) and drop in BMI (of -0.36 kg/m), while no significant difference was detected in other dietary comparisons. WC was lower with all diets compared to UD, with no significant difference across specific diets. There was no significant interaction of the results with the pre-specified sub-groups. The ROB was moderate to high, mostly related to unclear allocation concealment, high dropout rate and unclear or lack of blinding of participants, providers, and outcome assessors.

CONCLUSION

Dietary interventions extending over ≥12 months are superior to UD in inducing weight, BMI and WC loss. HFLC might be associated with a slightly higher WL compared with MM diets.

SYSTEMATIC TRIAL REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=103116, PROSPERO (CRD42018103116).

Address: Nutrition Department, School of Health Sciences, Modern University for Business and Sciences, Beirut, Lebanon.; Department of Clinical Nutrition, American University of Beirut Medical Center, Beirut, Lebanon.; York Medical School, University of Hull, York, United Kingdom.; Research & Programmes Department, Qualisus Consulting, Byblos, Lebanon.; Center for Research on Population and Health, Faculty of Health Sciences, American University of Beirut, Beirut, Lebanon.; Duke Global Health Institute, Duke University, Durham, NC, United States.; Department of Health Management and Policy, Faculty of Health Sciences, American University of Beirut, Beirut, Lebanon.; Faculty of Medicine, American University of Beirut, Beirut, Lebanon.; Department of Nutrition and Dietetics, Faculty of Health Sciences, Beirut Arab University, Beirut, Lebanon.; The European School of Management and Technology, Berlin, Germany.; Access to Nutrition Initiative, Utrecht, Netherlands.; Calcium Metabolism and Osteoporosis Program, WHO Collaborating Center for Metabolic Bone Disorders, American University of Beirut Medical Center, Beirut, Lebanon.

DOI: 10.3389/fnut.2022.821096