Breakfast intake and physical activity are associated with skeletal muscle mass and SMI in male Japanese workers

The Claim

Breakfast intake and physical activity are associated with skeletal muscle mass and SMI in male Japanese workers

This conclusion is most relevant to: Male Japanese workers (n=377).

What the Research Shows

The conclusion draws on 1 linked study. Highlights from the cited literature:

• ▸A cross-sectional study of lifestyle factors related to body mass index, skeletal muscle mass, and skeletal muscle index in male Japanese workers. (Nagoya journal of medical science, 2026) — In a cross-sectional study of 377 male Japanese workers, multiple regression analysis revealed that skeletal muscle mass and skeletal muscle index (SMI) were associated with age, BMI, breakfast intake, and waist circumference, with skeletal muscle mass also associated with heavy physical activity. The findings suggest that prioritizing breakfast intake and physical activity may help maintain muscle mass.

How It Works

The proposed biological pathway:

• ▸Breakfast intake may provide nutrients that support muscle protein synthesis
• ▸Physical activity stimulates muscle hypertrophy and maintenance
• ▸Higher BMI and waist circumference reflect overall body composition
• ▸Result: Breakfast and physical activity are associated with higher muscle mass

Who Might Benefit

Evidence fit by population:

• ▸Male Japanese workers (n=377)

Recommended Dose

N/A

Limitations & Caveats

Important context when interpreting this evidence:

• ▸Cross-sectional design prevents causal inference
• ▸Self-reported lifestyle factors may introduce recall bias
• ▸Sample limited to male Japanese workers, limiting generalizability
• ▸No sarcopenic obesity cases met AWGS 2019 criteria, so findings may not apply to sarcopenic populations

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