ProteinNEW2026-10

Effects of Body-Mass-Scaled Protein and Leucine Supplementation on Body Composition and Cardiometabolic Blood Markers During Weight Loss in Older Men-A Randomized Controlled Trial.

Pang Benedict Wei Jun, Yang Yifan, Cheon Bobby Kyungbeom — Nutrients

Summary

A study looked at whether protein or leucine supplements could help older men lose weight while preserving muscle and improving heart health markers. Researchers found that while the weight loss diet itself led to positive changes, adding these specific supplements didn't provide extra benefits for body composition or heart health in this group.

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Key points

Weight loss diets can improve body composition and heart health markers in older men.
This study tested if extra protein or leucine supplements offered more benefits during weight loss.
The supplements did not provide additional improvements for muscle or heart health markers beyond the diet itself.

What the study looked at

What question did the study ask? This study explored whether adding protein or the amino acid leucine supplements, adjusted for body weight, could further improve body composition and heart-related health markers in older men on a weight loss diet. The aim was to see if supplements offered benefits beyond the diet itself for muscle preservation and metabolic health. How was it studied? Sixty-one overweight older men followed a 28-day alternate-day fasting diet. They were split into three groups: one received no supplement, one a leucine supplement, and the third a protein supplement, with doses scaled to body weight. Researchers tracked changes in body composition, muscle strength, and various blood markers for heart health and diabetes. What did it find? The alternate-day fasting diet successfully led to weight loss, reduced body fat, and improved muscle strength, blood pressure, and cholesterol levels across all groups. However, adding either the protein or leucine supplement did not result in any significant *additional* improvements in body composition, muscle health, or most heart-related blood markers compared to the diet alone.

Dietary takeaway

For older men aiming for weight loss, focusing on a well-structured diet that promotes overall health benefits appears to be key. While protein is crucial for muscle health, this study suggests that simply adding protein or leucine supplements might not offer extra advantages for body composition or heart health beyond the benefits of the weight loss diet itself. Remember, this is just one study, and individual needs can vary, so consult a healthcare professional for personalized advice.

Abstract

Overweight and obesity are burgeoning health epidemics. Diets including alternate-day fasting (ADF) promote weight loss but risk significant muscle loss, posing health implications to seniors at risk of sarcopenia. Leucine, the key muscle protein synthesis (MPS) driver, effectively stimulates MPS with lower calorie intake than protein. However, the effects of body-mass-scaled protein and leucine intakes are unclear. To evaluate body-mass-scaled leucine or protein supplementation on body composition, sarcopenic, and cardiometabolic markers in older men during ADF. Sixty-one older men (BMI ≥ 23.0 kg/m) underwent 28 days of ADF, randomized across three calorie-matched supplement groups: Control (C: 0.0 g/kg protein, 0.0 g/kg leucine), Leucine (L: 0.0 g/kg protein, 0.08 g/kg leucine), or Protein (P: 0.4 g/kg protein, 0.04 g/kg leucine), consuming three doses on feeding days and one on fasting days. Dual-energy X-ray absorptiometry, sarcopenic metrics, and blood markers (blood pressure, lipid panels, diabetic profiles) were measured. There were no significant interactions ( > 0.05) in body composition, sarcopenic or health outcomes, except for diastolic blood pressure ( = 0.016) and HDL cholesterol ( = 0.013). There were significant main effects of time ( ≤ 0.05) with reductions in all body composition measures (excluding bone mineral density, = 0.274), systolic blood pressure and lipid profiles (total and LDL cholesterol, total/HDL cholesterol ratio, triglycerides), and improvements in all muscle strength and functional sarcopenic outcomes. Dietary interventions alone that increase leucine and/or protein intake did not result in additional measurable improvements during this four-week intervention on body composition, sarcopenic, and cardiometabolic outcomes during weight loss.

View on PubMed →DOI: 10.3390/nu18193255