There is no evidence to support the myth that maca root specifically promotes weight gain. Maca root is low in saturated fat, cholesterol, and sodium, and is a good source of healthy carbohydrates, such as fibre, which can help to keep you full longer. Maca root also contains many essential vitamins and minerals, such as vitamin C, copper, and iron.
Maca root has also been shown to help increase physical endurance and energy, which can help to support exercise and, therefore, the growth of lean muscle mass. In one study, participants experienced improved cycling times compared to a placebo group after supplementing with maca root extract for 14 days (1). In a 12-week study, participants reported improvements in mood and every level after taking 3 grams of maca daily (2).For these reasons, daily consumption of maca root can help to promote a healthy body composition when paired with regular exercise.
Referenced sources:
Stone, M, Ibarra, A, et al (2009). A pilot investigation into the effect of maca supplementation on physical activity and sexual desire in sportsmen.
Gonzales-Arimborgo, C, Yupanqui, I, et al (2016). Acceptability, Safety, and Efficacy of Oral Administration of Extracts of Black or Red Maca (Lepidium meyenii) in Adult Human Subjects: A Randomized, Double-Blind, Placebo-Controlled Study.