Protein and leucine added no measurable benefit in older men
In a 28-day randomised trial of 61 older men, extra protein or leucine added no measurable benefit overall during alternate-day fasting.
In a randomised trial, 61 older men followed alternate-day fasting for 28 days. Their body mass index, a measure of weight relative to height, was at least 23. Researchers assigned them to calorie-matched supplements containing no protein or leucine, leucine alone, or protein with leucine. Amounts per kilogram of body weight were 0.08 grams of leucine in the leucine group, and 0.4 grams of protein plus 0.04 grams of leucine in the protein group. Men took three doses on feeding days and one on fasting days.
Neither supplement added measurable improvements in body composition, muscle strength or function, or heart and metabolic health measures overall. Changes in diastolic blood pressure, the lower reading, and HDL cholesterol, often called “good” cholesterol, differed between groups. The abstract did not report the direction of those differences.
Why it matters
Muscle loss during weight loss is a concern for older people at risk of sarcopenia, a loss of muscle mass and strength. The trial addressed whether extra protein or leucine could help preserve muscle during fasting.
Caveats
The four-week trial could not establish longer-term effects, and its findings do not cover women. The abstract did not report adverse events.
