What should you do to optimize protein intake?
Aim for 1.2-1.6g of protein per kilogram of body weight daily, distributed across 3-5 meals with 20-40g per serving. Prioritize whole food sources like fish, poultry, legumes, eggs, and dairy.
Calculate your target: multiply your body weight in kilograms by 1.2-1.6 (moderately active) or 1.6-2.2 (athletes). For a 70kg adult, this means 84-112g per day. Distribute across meals rather than consuming most protein at dinner.
Practical portions: a palm-sized serving of chicken or fish provides about 30g, a cup of Greek yogurt 15-20g, 2 eggs 12g, a cup of lentils 18g, and a scoop of protein powder 20-25g.
How much protein do different populations need?
Requirements vary significantly: sedentary adults need 0.8-1.0g/kg/day, active adults 1.2-1.6g/kg, athletes 1.6-2.2g/kg, older adults 1.0-1.2g/kg minimum, and those losing weight 1.2-1.6g/kg to preserve muscle.
The International Society of Sports Nutrition recommends 1.4-2.0g/kg/day for exercising individuals. The PROT-AGE Study Group recommends 1.0-1.2g/kg/day for healthy older adults and 1.2-1.5g/kg/day for those with chronic disease (Source: Journal of the American Medical Directors Association, 2013).
During weight loss, higher protein intake (1.2-1.6g/kg) preserves lean body mass. A meta-analysis found that people consuming higher protein during caloric restriction lost significantly more fat and retained more muscle than those eating standard protein levels.
Why does protein distribution throughout the day matter?
Muscle protein synthesis is maximally stimulated by 20-40g of protein per meal. Eating most protein at dinner means missing opportunities to stimulate muscle building throughout the day.
Research shows muscle protein synthesis has a ceiling per meal — approximately 20-40g depending on body size and age. Consuming 60g at dinner and 10g at breakfast is less effective than 30g at each meal, even though daily total is the same.
The optimal approach is 3-5 meals each containing 20-40g of protein, spaced 3-5 hours apart. For older adults, 30-40g per meal may be the minimum effective dose due to anabolic resistance. Leucine content (found highest in whey, eggs, and meat) is the key trigger for muscle protein synthesis.
What are the best food sources of protein?
Animal sources (poultry, fish, eggs, dairy) provide complete proteins with high digestibility. Plant sources (legumes, tofu, tempeh, quinoa) are effective when eaten in variety throughout the day.
Protein quality is measured by the Digestible Indispensable Amino Acid Score (DIAAS). Top scorers: whole eggs (1.13), milk (1.14), chicken breast (1.08), whey protein (1.09). Plant proteins score lower but can be combined: soy (0.90), pea protein (0.82), rice protein (0.60).
High-protein foods ranked by protein per calorie: chicken breast (31g/165 cal), cod (20g/90 cal), Greek yogurt (15g/100 cal), tofu (10g/76 cal), lentils (18g/230 cal per cup). For muscle building, leucine content matters most — animal proteins are generally higher in leucine.
- Chicken breast — 31g per 3.5 oz, complete protein
- Salmon — 25g per 3.5 oz, plus omega-3s
- Eggs — 6g each, highly bioavailable
- Greek yogurt — 15-20g per cup
- Lentils — 18g per cooked cup, plus fiber
- Tofu (firm) — 10g per 3.5 oz
Do older adults need more protein?
Yes. Adults over 65 develop anabolic resistance — muscles respond less efficiently to protein, requiring 1.0-1.2g/kg/day minimum. Combined with resistance training, higher protein is the most effective anti-sarcopenia strategy.
Sarcopenia begins around age 30 with 3-8% muscle mass lost per decade, accelerating after 60. The PROT-AGE Study Group recommends 1.0-1.2g/kg/day for healthy older adults. The per-meal threshold is higher in older adults (~35-40g vs. 20-25g in younger adults).
Combining higher protein intake with resistance training 2-3 times per week is far more effective than either alone. Leucine supplementation (2-3g per meal) can partially overcome anabolic resistance. Despite concerns, higher protein in healthy older adults does not increase kidney disease risk.
Can you get enough protein on a plant-based diet?
Yes, but it requires more planning. Plant proteins have lower digestibility and leucine content, so vegans may need 10-20% more total protein. Combining legumes, grains, soy, and nuts provides all essential amino acids.
Key strategies: eat a variety of protein sources, prioritize higher-quality plant proteins (soy, pea, quinoa), consume slightly more total protein (1.4-2.0g/kg for plant-based athletes), and consider supplementing with leucine or BCAAs if training intensely.
A 2019 meta-analysis found no difference in muscle mass gains between animal and plant protein when total protein and leucine intake were equated. Practical plant-based meals: tofu scramble with black beans (30g), lentil dal with quinoa (25g), tempeh stir-fry with edamame (35g).
