Dietary intake and weight loss in obese adults during GLP-1 receptor agonist treatment
- 1Faculty of Food Science and Nutrition, University of Iceland, Reykjavik, Iceland
Abstract
Background: Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have been used for weight management due to their effectiveness in reducing appetite and promoting weight loss. Across many sponsored trials, participants typically received lifestyle interventions including dietary counseling and guidance on physical activity. The aim of the present study was to investigate dietary intake and weight loss after GLP-1 RA treatment in adults who did not receive a detailed accompanying lifestyle intervention reflecting a real word setting.
Methods: In this prospective observational study, adults (N = 44) with obesity were assessed one month and five months after initiating semaglutide treatment. Dietary intake was assessed using a 3-day food diary, while body weight and body composition were measured using bioelectrical impedance analysis.
Results: Of the participants (45.4 ± 13.4 years, 25% male), 54.5% reported regular resistance exercise. The mean energy intake was 1489 kcal/day. Dietary intake was characterized by low consumption of whole grains, fruits and vegetables, and fish, as well as low dietary fiber and several nutrients, e.g., vitamin D and calcium. Mean daily protein intake was 0.75 g/kg body weight, with 63% of participants consuming less than 0.8 g/kg. Mean BMI was 37.1 ± 5.15 kg/m2 at baseline and the participants experienced a weight loss of 8.3% after 5 months, of which 74.5% was attributable to fat mass and 25.5% to fat-free mass (19.0% skeletal muscle).
Conclusions: Adults initiating GLP-1 RA treatment without accompanying lifestyle programme exhibited low energy intake and low diet quality. More than half reported regular resistance exercise and weight loss was primarily driven by fat mass reduction, although a significant proportion of lean mass was also lost. These findings indicate the need for early nutritional guidance focusing on diet quality, adequate protein intake, and strategies to preserve lean body mass during GLP-1 RA treatment.
Key messages: • Adults initiating GLP-1 RA treatment without accompanying lifestyle programme exhibited low energy intake and low diet quality.
• Body weight loss was primarily driven by fat mass reduction, although a significant proportion of lean mass was also lost.
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BibTeX
@article{ramel2026dietary,
title = {{Dietary intake and weight loss in obese adults during GLP-1 receptor agonist treatment}},
author = {A Ramel},
journal = {The European Journal of Public Health},
year = {2026},
month = oct,
doi = {10.1093/eurpub/ckag169.1321},
url = {https://doi.org/10.1093/eurpub/ckag169.1321},
note = {CC BY-NC 4.0},
}
RIS
TY - JOUR
TI - Dietary intake and weight loss in obese adults during GLP-1 receptor agonist treatment
AU - A Ramel
PY - 2026
DA - 2026/10/01
JO - The European Journal of Public Health
DO - 10.1093/eurpub/ckag169.1321
UR - https://doi.org/10.1093/eurpub/ckag169.1321
AB - Background: Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have been used for weight management due to their effectiveness in reducing appetite and promoting weight loss. Across many sponsored trials, participants typically received lifestyle interventions including dietary counseling and guidance on physical activity. The aim of the present study was to investigate dietary intake and weight loss after GLP-1 RA treatment in adults who did not receive a detailed accompanying lifestyle intervention reflecting a real word setting. Methods: In this prospective observational study, adults (N = 44) with obesity were assessed one month and five months after initiating semaglutide treatment. Dietary intake was assessed using a 3-day food diary, while body weight and body composition were measured using bioelectrical impedance analysis. Results: Of the participants (45.4 ± 13.4 years, 25% male), 54.5% reported regular resistance exercise. The mean energy intake was 1489 kcal/day. Dietary intake was characterized by low consumption of whole grains, fruits and vegetables, and fish, as well as low dietary fiber and several nutrients, e.g., vitamin D and calcium. Mean daily protein intake was 0.75 g/kg body weight, with 63% of participants consuming less than 0.8 g/kg. Mean BMI was 37.1 ± 5.15 kg/m2 at baseline and the participants experienced a weight loss of 8.3% after 5 months, of which 74.5% was attributable to fat mass and 25.5% to fat-free mass (19.0% skeletal muscle). Conclusions: Adults initiating GLP-1 RA treatment without accompanying lifestyle programme exhibited low energy intake and low diet quality. More than half reported regular resistance exercise and weight loss was primarily driven by fat mass reduction, although a significant proportion of lean mass was also lost. These findings indicate the need for early nutritional guidance focusing on diet quality, adequate protein intake, and strategies to preserve lean body mass during GLP-1 RA treatment. Key messages: • Adults initiating GLP-1 RA treatment without accompanying lifestyle programme exhibited low energy intake and low diet quality. • Body weight loss was primarily driven by fat mass reduction, although a significant proportion of lean mass was also lost.
SN - 1101-1262
SN - 1464-360X
ER -