Shvalb NF, Lazar L, Demol S, et al. - In short and lean healthy boys on the verge of pubertal onset, a six-month intervention with a nutritional formula exhibited feasibility, effectiveness and safety for promoting weight gain and increasing muscle mass. In addition, good formula consumption prevented the expected decline in height-SDS in the older candidates.

• This prospective, double-blinded, randomized, controlled trial recruited 160 boys (age ≥ 10 years) between July 2015 and January 2020.

• One hundred twenty-six boys (80%) completed 6 months' intervention.

• The formula and placebo groups had similar baseline age, height-SDS, weight-SDS, BMI-SDS, body composition, and dietary intake.

• Consumers of the ‘good' formula (intake of ≥ 50% of the recommended dose, n = 30) gained considerably more weight-SDS, BMI-SDS, fat-free-mass and muscle mass than consumers of the ‘poor' formula (n = 35) and the placebo group (n = 61).

• Positive dose-response correlations between formula consumption and changes in the outcome parameters studied, including Δheight-SDS, were found only in the formula group.

• Boys aged > 11.4 years who consumed ‘good’ formula maintained their Δheight-SDS, whereas ‘poor’ consumers and the placebo group of the same age lost Δheight-SDS.