Examining differences between overweight women and men in 12-month weight loss study comparing healthy low-carbohydrate vs. low-fat diets - PubMed (original) (raw)
Randomized Controlled Trial
. 2021 Jan;45(1):225-234.
doi: 10.1038/s41366-020-00708-y. Epub 2020 Nov 14.
Affiliations
- PMID: 33188301
- PMCID: PMC7752762
- DOI: 10.1038/s41366-020-00708-y
Randomized Controlled Trial
Examining differences between overweight women and men in 12-month weight loss study comparing healthy low-carbohydrate vs. low-fat diets
Lucia Aronica et al. Int J Obes (Lond). 2021 Jan.
Abstract
Background/objectives: Biological sex factors and sociocultural gender norms affect the physiology and behavior of weight loss. However, most diet intervention studies do not report outcomes by sex, thereby impeding reproducibility. The objectives of this study were to compare 12-month changes in body weight and composition in groups defined by diet and sex, and adherence to a healthy low carbohydrate (HLC) vs. healthy low fat (HLF) diet.
Participants/methods: This was a secondary analysis of the DIETFITS trial, in which 609 overweight/obese nondiabetic participants (age, 18-50 years) were randomized to a 12-month HLC (n = 304) or HLF (n = 305) diet. Our first aim concerned comparisons in 12-month changes in weight, fat mass, and lean mass by group with appropriate adjustment for potential confounders. The second aim was to assess whether or not adherence differed by diet-sex group (HLC women n = 179, HLC men n = 125, HLF women n = 167, HLF men n = 138).
Results: 12-month changes in weight (p < 0.001) were different by group. HLC produced significantly greater weight loss, as well as greater loss of both fat mass and lean mass, than HLF among men [-2.98 kg (-4.47, -1.50); P < 0.001], but not among women. Men were more adherent to HLC than women (p = 0.02). Weight loss estimates within group remained similar after adjusting for adherence, suggesting adherence was not a mediator.
Conclusions: By reporting outcomes by sex significant weight loss differences were identified between HLC and HLF, which were not recognized in the original primary analysis. These findings highlight the need to consider sex in the design, analysis, and reporting of diet trials.
Conflict of interest statement
The authors declare that they have no conflict of interest.
Figures
Fig. 1. 12-month changes in weight, fat mass, and lean mass by sex and diet, adjusted for baseline weight and baseline body fat percentage.
Estimated between-group differences (95% CI). Weight data were available at baseline and 3, 6, and 12 months, respectively, as follows: women on HLF, n = 167, 151, 131, 120; women on HLC, n = 179, 155, 144, 131; men on HLF, n = 138, 119, 97, 96; and men on HLC, n = 125, 108, 95, 89. Fat mass and lean mass data were available at baseline, 6, 12 months, respectively, as follows (cohorts 2–5): women on HLF, n = 131, 107, 106; women on HLC, n = 145, 121, 118; men on HLF, n = 97, 75, 79; men on HLC, n = 93, 73, 78.
Fig. 2. Differences in 12-month diet adherence by sex and diet type.
Estimated between-group differences in weight-adjusted standardized adherence (WASA) scores. Higher values indicate higher adherence relative to the average adherence across all groups.
References
- Clayton JA. Applying the new SABV (sex as a biological variable) policy to research and clinical care. Physiol Behav. 2018;187:2–5. - PubMed
- Greenberg I, Stampfer MJ, Schwarzfuchs D, Shai I. Adherence and success in long-term weight loss diets: the dietary intervention randomized controlled trial (DIRECT) J Am College Nutr. 2009;28:159–68.. - PubMed
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Grants and funding
- R01 DK091831/DK/NIDDK NIH HHS/United States
- K12 GM088033/GM/NIGMS NIH HHS/United States
- UL1 TR001085/TR/NCATS NIH HHS/United States
- P30 DK116074/DK/NIDDK NIH HHS/United States
- UL1 TR003142/TR/NCATS NIH HHS/United States