New Study Finds That Plant-Based Low-Carbohydrate Diets Slow Weight Gain Compared to Animal-Based Low-Carb Diets
A new study has compared people eating low-carbohydrate diets. All groups gained weight on average, but those eating more plant-based foods and favoring whole grains instead of processed grains and sugars gained less weight than people following a diet that focused on animal products. The study used data from several large cohort studies that followed people eating a low-carbohydrate diet over four years.
Question Are low-carbohydrate diets (LCDs) associated with long-term weight change, and does the source and quality of macronutrients within LCDs influence these associations?
Findings In this cohort study using data from 3 large prospective cohort studies among 123 332 individuals, LCDs that emphasized high-quality proteins, fats and carbohydrates from whole grains and other healthy plant-based foods were significantly associated with slower weight gain in the long term. In contrast, LCDs emphasizing animal-sourced proteins and fats or refined carbohydrates were associated with faster weight gain.
Meaning These findings underscore the importance of diet quality within LCD patterns for long-term weight management.
Results A total of 123 332 participants (mean [SD] age, 45.0 [9.7] years; 103 320 [83.8%] female) were included in this study. The median carbohydrate intake (as a percentage of energy) of the highest quintiles of TLCD score at baseline ranged from 38.3% in HPFS to 40.9% in NHSII. Mean weight gain over 4-year intervals among participants varied from 0.8 kg in the HPFS to 1.8 kg in the NHSII. After adjusting for demographics and baseline and concomitant changes of selected lifestyle factors, each 1-SD increase in TLCD score was associated with 0.06 (95% CI, 0.04-0.08) kg more weight gain over the 4-year periods. Similarly, participants gained 0.13 (95% CI, 0.11 to 0.14) kg per each 1-SD increase in ALCD score and 0.39 (95% CI, 0.37 to 0.40) kg per each 1-SD change in ULCD score. In contrast, each 1-SD increase in VLCD score was associated with 0.03 (95% CI, 0.01 to 0.04) kg less weight gain, and each 1-SD increase in HLCD score was associated with 0.36 (95% CI, 0.35 to 0.38) kg less weight gain. The associations were more pronounced among obese individuals (per 1-SD increase in HLCD score: BMI ≥30, 0.88 [95% CI, 0.80, 0.97] kg less weight gain; BMI <25, 0.23 [95% CI, 0.20, 0.26] kg less weight gain; P for interaction < .001).
Conclusions and Relevance These findings suggest that the quality of LCDs may play a critical role in modulating long-term weight change. Only LCDs that emphasized high-quality protein, fat, and carbohydrates from whole grains and other plant-based foods were associated with less weight gain.
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