Researchers from Harvard (under the supervision of Dr Frank Hu) looked at data from three large cohorts—the Nurses’ Health Study, the Nurses’ Health Study 2, and the Health Professionals Follow-Up Study—for a total of 126,982 adult participants with more than 20 years of follow-up.
On average, participants gained a mean of 0.90 kg (HPFS) to 1.98 kg (NHS2) over 4-y intervals. Different types of plant-based diet indices were associated with different amounts of weight gain.
- A 1-SD increase in intake of a healthful version of a plant-based diet index (emphasizing whole grains, fruits/vegetables, nuts/legumes, vegetable oils, tea/coffee) was associated with 0.68 kg less weight gain over 4-y periods (95% CI: 0.69, 0.66 kg; P < 0.001).
- A1-SD increase in an unhealthful version of a plant-based diet index (emphasizing refined grains, potato/fries, sweets, sweetened drinks/juices) was associated with 0.36 kg more weight gain (95% CI: 0.34, 0.37 kg, P < 0.001).
Reference: Satija A, Malik V, Rimm EB, Sacks F, Willett W, Hu FB. Changes in intake of plant-based diets and weight change: results from 3 prospective cohort studies. Am J Clin Nutr. Published ahead of print May 25, 2019.