How much protein should I eat per meal?

Research suggests that 20–40 g of high-quality protein per meal maximally stimulates muscle protein synthesis (MPS). This translates to roughly 0.4 g/kg body weight per meal. Meals below ~20 g may not reach the leucine threshold (~2.5–3 g leucine) needed to trigger MPS, while meals above 40 g do not appear to dramatically increase MPS further — though the extra protein is still used for other metabolic purposes. Spreading your daily protein across 3–5 meals is more effective than consuming most of it in one or two sittings.

Can too much protein damage your kidneys?

In healthy adults without pre-existing kidney disease, high protein intake has not been shown to impair kidney function. The kidneys adapt to increased nitrogen excretion efficiently. The concern originated from studies of people with chronic kidney disease (CKD), where excess protein accelerates disease progression — but this does not apply to healthy kidneys. If you have kidney disease or a family history of it, speak with your doctor before following a high-protein diet.

What are the best protein sources for muscle building?

Complete proteins — those containing all nine essential amino acids in adequate proportions — are most effective for muscle protein synthesis. Top sources: chicken breast (31 g/100 g), lean beef (26 g/100 g), eggs (6 g each, excellent leucine profile), Greek yogurt (10 g/100 g), cottage cheese (11 g/100 g), salmon (20 g/100 g), and whey protein (~25 g per scoop). Plant sources such as tofu (8 g/100 g), edamame (11 g/100 g), and lentils (9 g/100 g cooked) can meet needs when combined or consumed in sufficient quantity.

Do I need protein powder to build muscle?

No. Protein powder is a convenient supplement, not a requirement. If you can meet your daily protein target through whole foods, there is no evidence that adding protein powder provides additional muscle-building benefit. Protein supplements are useful when whole-food sources are inconvenient (e.g., post-workout when a meal is impractical), when appetite is low, or when dietary restrictions make hitting targets challenging. The protein source — powder or food — matters less than total daily intake and leucine content.

Does protein timing around workouts matter?

Timing matters, but less than total daily intake. The "anabolic window" — the idea that you must consume protein within 30 minutes of training — is overstated. Research shows the post-exercise period where muscles are sensitised to protein synthesis lasts at least 5–6 hours. Practically, aim to consume 20–40 g of protein within a few hours before or after training. If you train fasted, consuming protein immediately after is more important. If you had a protein-rich meal 2–3 hours before training, post-workout protein can wait until your next meal.

How much protein do I need for weight loss?

During a calorie deficit, protein requirements increase significantly compared to maintenance. A meta-analysis by Morton et al. (2018) found that intakes of 1.62 g/kg/day preserved lean mass during fat loss. Many sports dietitians recommend 1.8–2.4 g/kg/day during active fat loss, particularly when training hard. The higher end of this range is appropriate when the deficit is large, body fat percentage is low (more risk of muscle loss), or resistance training volume is high.

Is plant protein as effective as animal protein for muscle building?

Animal proteins (whey, eggs, meat, dairy) generally have a higher leucine content and better amino acid profiles than most plant sources. However, a 2023 systematic review by Lim et al. found no significant difference in muscle gain between plant and animal protein diets when total protein and leucine intake were matched. Plant-based eaters should aim for slightly higher total protein (approximately 1.2x the standard target, around 1.9–2.6 g/kg) to compensate for lower digestibility and leucine concentration, and mix protein sources (e.g., rice + pea protein, lentils + tofu) to improve the amino acid profile.

Should I use lean body mass instead of total body weight to calculate protein?

Yes, if you are significantly overweight. Standard protein recommendations in g/kg are based on total body weight at a healthy or athletic weight. If someone weighs 120 kg but has a lean body mass of 70 kg, using total weight would recommend an unrealistically high protein target. The better approach for overweight individuals is to use either lean body mass or adjusted body weight (midpoint between ideal and actual weight). At a healthy weight, total body weight works fine.

How Much Protein Do You Need?

Protein is the most important macronutrient for body composition. It is the raw material from which muscle is built and repaired, the most satiating nutrient per calorie, and the only macro with a high enough thermic effect to meaningfully raise your daily calorie expenditure. Whether your goal is fat loss, muscle gain, or simply ageing well, protein intake is the first dial to set correctly.

Most people either consume too little protein (relying on vague recommendations like “eat more chicken”) or too much supplementation without hitting their actual daily targets. This guide gives you the evidence-based numbers, explains the science behind them, and provides a practical framework for hitting your target from real food.

The Science of Protein Needs

Why the Official RDA is Not Enough

The Recommended Dietary Allowance (RDA) for protein is 0.8 g per kilogram of body weight per day. This figure is widely cited but frequently misunderstood: it represents the minimum intake to prevent deficiency in sedentary adults — not the optimal intake for health, body composition, or physical performance.

For context, a 75 kg sedentary adult would need only 60 g of protein per day to meet the RDA. That is enough to avoid muscle wasting and maintain basic nitrogen balance. It is not enough to preserve lean mass during a calorie deficit, support muscle protein synthesis after resistance training, or maximise satiety on a fat-loss diet.

Evidence-Based Recommendations by Goal

The International Society of Sports Nutrition (ISSN), the American College of Sports Medicine (ACSM), and independent meta-analyses consistently support higher targets:

Sedentary adults (general health): 1.0–1.2 g/kg/day — above the RDA minimum to better support muscle maintenance as age increases.
Fat loss: 1.6–2.4 g/kg/day. A landmark meta-analysis by Morton et al. (2018, British Journal of Sports Medicine) of 49 randomised controlled trials found that protein intakes up to 1.62 g/kg/day maximised lean mass retention. Many practitioners recommend the upper end (2.0–2.4 g/kg) during aggressive deficits.
Muscle gain: 1.6–2.2 g/kg/day. A systematic review by Schoenfeld and Aragon (2018, Journal of the International Society of Sports Nutrition) found no significant additional benefit beyond 2.2 g/kg/day for muscle accretion. Higher intakes are not harmful but offer diminishing returns.
Endurance athletes: 1.2–1.6 g/kg/day. Lower demands for muscle hypertrophy, but protein is still important for muscle repair and preventing the breakdown of amino acids for fuel during prolonged sessions.
Older adults (over 65): 1.2–2.0 g/kg/day. Anabolic resistance means older muscles require more protein stimulation to achieve the same MPS response as younger adults. Research from Paddon-Jones et al. supports higher targets to prevent sarcopenia (age-related muscle loss).

Muscle Protein Synthesis and the Leucine Threshold

Protein builds muscle by stimulating muscle protein synthesis (MPS) — the process of assembling new muscle proteins from amino acids. MPS is primarily triggered by the amino acid leucine, which acts as a molecular signal that “switches on” protein synthesis in muscle cells.

Research by Norton and Layman (2006) and subsequent studies have identified a leucine threshold of approximately 2.5–3 g per meal to maximally trigger MPS. This is typically achieved with 20–40 g of high-quality protein per meal (depending on the leucine density of the food source).

Distributing protein across 3–5 meals per day repeatedly stimulates MPS throughout the day, which is more effective for muscle building and preservation than concentrating most of your daily protein in one or two meals.

How to Calculate and Hit Your Protein Target

Step 1: Determine Your Body Weight in Kilograms

If you are at a healthy body weight, use your actual weight. If you are significantly overweight, use your lean body mass (LBM) or adjusted body weight to avoid an unrealistically high protein target. Lean body mass is estimated as: total body weight × (1 − body fat percentage). If you do not know your body fat percentage, use your ideal body weight as a conservative baseline.

Step 2: Multiply by Your Target Range

Choose a daily target based on the goal ranges above. For most active people pursuing body composition goals, 1.6–2.2 g/kg/day covers the evidence-based sweet spot. A 75 kg person following a fat-loss programme would aim for 120–165 g of protein per day.

Step 3: Distribute Across Meals

Divide your daily target across meals to hit 20–40 g per sitting. A 150 g daily target across four meals averages 37.5 g per meal — achievable with:

Breakfast: 200 g Greek yogurt + 2 eggs = ~30 g
Lunch: 150 g grilled chicken breast = ~46 g
Snack: 200 g cottage cheese = ~22 g
Dinner: 150 g salmon + 100 g lentils = ~42 g

High-Protein Foods Reference

Chicken breast: 31 g protein per 100 g
Lean beef (sirloin): 26 g per 100 g
Salmon: 20 g per 100 g
Eggs: 6 g each (whole egg)
Greek yogurt (0% fat): 10 g per 100 g
Cottage cheese: 11 g per 100 g
Whey protein powder: 22–25 g per 30 g scoop
Tofu (firm): 8 g per 100 g
Edamame (cooked): 11 g per 100 g
Lentils (cooked): 9 g per 100 g

Common Protein Mistakes

Using total body weight when very overweight: A person weighing 140 kg with 40% body fat does not need 224–308 g of protein per day (1.6–2.2 × 140). Using lean body mass (~84 kg) gives a more appropriate target of 134–185 g/day.
Front-loading all protein into one meal: Consuming 150 g of protein at dinner and very little at breakfast and lunch misses multiple MPS stimulation opportunities throughout the day. Research by Areta et al. (2013) found that distributing protein more evenly produced greater MPS over 12 hours than a bolus pattern.
Relying only on supplements: Protein powders are a supplement to whole foods, not a replacement. Whole protein sources provide leucine, micronutrients, satiety, and other bioactive compounds that powders do not. Use supplements to fill gaps, not as the foundation of your protein intake.
Thinking more is always better: Above approximately 2.2–2.5 g/kg/day, additional protein provides minimal additional muscle-building benefit. The body does not store excess protein as muscle — it oxidises it for energy. There is no harm in consuming more, but the extra food cost and meal volume are unnecessary.
Ignoring protein quality: Not all 20 g protein sources are equivalent. A source high in leucine (whey, eggs, meat) stimulates MPS more effectively than the same gram weight from a lower-leucine source (peas, rice). Plant-based eaters should prioritise leucine-rich sources or consume slightly higher total amounts to compensate.