Low carbohydrate diet macronutrient quality and weight change

In this study using data from three large prospective cohort studies among 123,000 individuals, low-carbohydrate diets 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, low-carbohydrate diets emphasizing animal-sourced proteins and fats or refined carbohydrates were associated with faster weight gain.

The associations of low-carbohydrate diets (LCDs) with long-term weight management remains unclear, and the source and quality of macronutrients within LCDs are less explored.

A total of 123 332 participants (mean [SD] age, 45.0 years; 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 total LCD score was associated with 0.06 kg more weight gain over the 4-year periods. Similarly, participants gained 0.13 kg per each 1-SD increase in an animal-based LCD score and 0.39 kg per each 1-SD change in an unhealthy LCD score. In contrast, each 1-SD increase in a vegetable-based LCD score was associated with 0.03 kg less weight gain, and each 1-SD increase in a healthy LCD score was associated with 0.36 kg less weight gain.

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.

Reference: Liu B, Hu Y, Rai SK, Wang M, Hu FB, Sun Q. Low-Carbohydrate Diet Macronutrient Quality and Weight Change. JAMA Netw Open. 2023;6(12):e2349552. DOI:10.1001/jamanetworkopen.2023.49552