Intro
Protein is the foundation of lean tissue, metabolic health, and recovery. Adequate intake preserves muscle mass, stabilizes blood glucose, and supports long-term weight management.
Key Points
- Aim for 1.6–2.2 g/kg body weight per day for optimal muscle maintenance.
- Evenly distribute protein across 3–4 meals to maximize muscle synthesis.
- Combine with resistance training and adequate calories for best results.
- Both plant and animal proteins can meet requirements with proper variety.
Background
Muscle protein synthesis (MPS) requires essential amino acids — particularly leucine — to trigger repair and growth. As people age or reduce calorie intake, MPS efficiency declines, making protein intake even more crucial. Balanced intake reduces sarcopenia and improves metabolic rate.
Mechanisms
- Stimulates MPS: amino acids trigger cellular repair and regeneration.
- Improves body composition: preserves muscle while reducing fat mass.
- Supports metabolic flexibility: stabilizes glucose and appetite control.
- Boosts thermogenesis: digestion and metabolism of protein slightly raise daily energy expenditure.
Recommendations
| Goal | Recommended Intake |
|---|---|
| General health | 1.2–1.6 g/kg/day |
| Muscle gain / resistance training | 1.6–2.2 g/kg/day |
| Weight loss (preserve muscle) | 1.8–2.4 g/kg/day |
Divide protein evenly across meals (≈25–40 g per meal). Post-exercise intake enhances recovery.
Sources
- Animal: eggs, chicken, fish, beef, dairy, whey protein
- Plant: soy, lentils, tofu, chickpeas, quinoa, peas
Vegetarians can combine complementary plant proteins to meet amino acid needs.
Safety and Side Effects
Protein is safe for most people. Myths about kidney damage stem from misapplied renal-disease research. Staying hydrated and balancing fiber helps digestion. Excess protein may displace other nutrients if total calories are restricted too tightly.
Risks / Benefits / Prognosis
Benefits:
- Maintains muscle and metabolic health
- Improves satiety and weight control
- Supports immunity and recovery
Risks:
- Minimal in healthy adults; digestive discomfort if extremely high intake
Prognosis:
Adequate protein is essential for healthy aging, body composition, and long-term metabolic stability.
FAQ
Q: Can protein help with fat loss?
A: Yes. Protein increases satiety and helps retain lean mass while reducing fat.
Q: What time of day is best to eat protein?
A: Evenly spaced through the day — not just post-workout — to maximize synthesis.
Q: Are plant proteins enough?
A: Yes, when combined (e.g., beans + rice, soy + grains) to cover all amino acids.
Q: Do older adults need more protein?
A: Often yes — anabolic resistance means older adults should target the higher end (1.8–2.2 g/kg/day).
Further Reading
- WHO Protein Requirements Report
- PubMed: Protein Intake and Muscle Health
- Examine.com: Protein Research Summary