Healthy plant-based diet tied to less weight gain

A diet rich in healthier plant foods helps prevent weight gain over time, results from three prospective cohort studies have shown.

“This supports current recommendations to increase intake of healthy plant foods, and [to reduce] intake of less-healthy plant foods and animal foods, for improved health outcomes,” the authors said.

Data were sourced from three ongoing prospective, observational cohort studies in the US, namely the Nurses’ Health Study (NHS), NHS2 and the Health Professionals Follow-up Study (HPFS), including a total of 126,982 adult men and women. The authors collected self-reported diet data every 4 years to estimate weight change over a follow-up of >20 years.

Participants gained a mean of 0.90 kg (HPFS) to 1.98 kg (NHS2) over 4-year intervals. An association was found between plant-based diets and weight gain.

Adjustments for potential confounders, including concomitant changes in other lifestyle factors, showed that a 1-SD increase in intake of an overall plant-based diet index correlated with 0.04-kg less weight gain (95 percent CI, 0.05–0.02 kg; p<0.001) over 4-year periods.

A 1-SD increase in intake of a healthful plant-based diet (ie, whole grains, fruits/vegetables, nuts/legumes, vegetable oils, tea/coffee) correlated with 0.68-kg less weight gain (0.69–0.66 kg; p<0.001) over 4-year intervals.

On the other hand, a 1-SD increase in intake of an unhealthful plant-based diet (ie, refined, grains, potato/fries, sweets, sweetened drinks/juices) correlated with 0.36-kg more weight gain (0.34–0.37 kg; p<0.001) over 4-year periods.

“Studies have found beneficial effects of plant-based diets on weight,” the authors said. “However, not all plant foods are necessarily beneficial.”