Ask ten people how much protein they need and you will get ten different answers. The official recommendation — 0.8 grams per kilogram of body weight per day — is widely cited, but it is frequently misunderstood. That number is a minimum to prevent deficiency in sedentary adults, not a target for optimal health, body composition, or performance.
This guide covers what the research actually shows: how protein requirements change depending on your goal, why the standard recommendation falls short for most active people, and a practical breakdown of how to meet your target from food.
The Official Recommendation Is a Floor, Not a Ceiling
The Recommended Dietary Allowance (RDA) for protein — 0.8 g/kg per day for adults — was established by the WHO, FAO, and UNU based on nitrogen balance studies in sedentary individuals. It represents the amount needed to prevent deficiency and maintain basic bodily function, not the amount that supports muscle maintenance, weight management, or active recovery.
For a 70 kg adult, 0.8 g/kg translates to just 56 g of protein per day. While this is adequate for someone who is sedentary and not pursuing any body composition goals, multiple independent research groups have found that higher intakes consistently produce better outcomes across weight loss, muscle gain, ageing, and athletic performance.
Protein Requirements by Goal
The appropriate protein intake depends on what you are trying to achieve. Research has established reasonably consistent ranges for each goal, though individual variation exists.
| Goal | Target Range (g/kg/day) | For a 70 kg Adult |
|---|---|---|
| General health / sedentary | 0.8–1.0 g/kg | 56–70 g |
| Weight loss (preserving muscle) | 1.2–1.6 g/kg | 84–112 g |
| Muscle gain (resistance training) | 1.6–2.2 g/kg | 112–154 g |
| Athletic performance | 1.4–2.0 g/kg | 98–140 g |
| Older adults (65+) | 1.0–1.5 g/kg | 70–105 g |
Why Higher Protein Supports Weight Loss
Beyond simply preserving muscle during a calorie deficit, protein affects weight management through three distinct mechanisms, each well-documented in the research literature.
1. Satiety — protein reduces hunger more than carbohydrates or fat
In a carefully controlled trial, Weigle et al. (2005) increased dietary protein from 15% to 30% of total calories while keeping carbohydrates and fat constant. Participants spontaneously reduced their calorie intake by an average of 441 kcal per day and lost an average of 4.9 kg over 12 weeks — without any deliberate calorie restriction. The researchers attributed this primarily to protein's superior effect on satiety hormones, including reduced ghrelin and increased peptide YY.
2. Thermic effect — protein requires more energy to digest
The thermic effect of food (TEF) is the energy cost of digesting and metabolising a nutrient. Protein has the highest TEF of any macronutrient: approximately 20–30% of its calories are expended during digestion, compared to 5–10% for carbohydrates and 0–3% for fat. Increasing protein as a proportion of calories modestly elevates total daily energy expenditure.
3. Lean mass preservation — maintaining muscle protects metabolic rate
Rapid weight loss without adequate protein accelerates the loss of lean muscle mass alongside body fat. Since muscle is metabolically active tissue, losing it reduces resting metabolic rate — one of the primary drivers of weight regain after dieting. Helms et al. (2014) recommend protein intakes of 2.3–3.1 g/kg of lean body mass for drug-free athletes in a calorie deficit specifically to preserve muscle during the weight loss phase.
Older Adults Need More Protein, Not Less
Skeletal muscle mass declines by approximately 3–8% per decade after age 30, accelerating after age 60 — a process called sarcopenia. Older adults also develop anabolic resistance: a reduced ability to synthesise muscle protein from the same amount of dietary protein compared to younger adults. The PROT-AGE Study Group (Bauer et al., 2013), a European consensus panel, recommends that healthy adults over 65 consume at least 1.0–1.2 g of protein per kilogram per day — substantially above the RDA of 0.8 g/kg. Those with acute or chronic illness, injury, or who engage in regular resistance exercise are advised to aim for 1.2–1.5 g/kg per day. General educational information only; discuss specific targets with a healthcare professional.
How to Calculate Your Protein Target
The calculation is straightforward once you know your goal range:
- Find your body weight in kilograms. If you weigh in pounds, divide by 2.205. (Example: 154 lbs ÷ 2.205 = 70 kg)
- Select the appropriate range for your goal from the table above.
- Multiply. A 70 kg person targeting muscle gain at 1.8 g/kg needs 126 g of protein per day.
If you are significantly overweight, calculating protein from your current weight may set a target that is unnecessarily high. In practice, using your goal body weight or a weight in the healthy BMI range for your height gives a more appropriate protein target during weight loss. This approach is commonly used in clinical nutrition settings.
Best Protein Sources
Not all protein sources are equal in terms of amino acid completeness, digestibility, or leucine content — the amino acid most directly responsible for stimulating muscle protein synthesis. Animal proteins are generally complete sources; plant proteins vary and often benefit from combining multiple sources.
| Food | Serving | Protein | Notes |
|---|---|---|---|
| Chicken breast (cooked) | 100 g | ~31 g | Complete protein; high leucine |
| Canned tuna (drained) | 100 g | ~25 g | Convenient; low cost |
| Salmon (cooked) | 100 g | ~25 g | Also provides omega-3 fatty acids |
| Eggs | 2 large | ~13 g | Complete protein; highly bioavailable |
| Greek yogurt (plain, 0%) | 200 g | ~20 g | Good calcium source; varies by brand |
| Cottage cheese | 100 g | ~11 g | Slow-digesting casein protein |
| Firm tofu | 100 g | ~8 g | Complete plant protein; leucine content lower than meat |
| Lentils (cooked) | 100 g | ~9 g | Also high in fibre; combine with grain for complete amino acids |
| Edamame (cooked) | 100 g | ~11 g | Complete plant protein; good snack option |
Practical Tips for Hitting Your Target
Knowing your target is the easy part. Consistently reaching it each day is where most people struggle. A few evidence-informed strategies help.
Distribute protein across meals rather than concentrating it
Research on muscle protein synthesis suggests that spreading intake across three to four meals — each containing roughly 20–40 g of protein — produces better outcomes than consuming the same total amount in one or two large meals. This is because there is a ceiling on how much muscle protein synthesis a single dose of protein can stimulate; amounts beyond approximately 40 g in a single meal appear to offer diminishing returns for muscle building specifically.
Anchor every meal with a dedicated protein source
Incidental protein from bread, nuts, or vegetables adds up slowly and makes it difficult to reach higher targets reliably. Building each meal around a primary protein source — chicken, fish, eggs, Greek yogurt, tofu, or legumes — makes it far easier to hit daily goals without tracking every gram obsessively.
Breakfast is typically the weakest protein meal
Survey data consistently shows that most people consume significantly less protein at breakfast than at lunch or dinner. For those struggling to meet daily targets, breakfast represents the easiest opportunity for improvement: eggs, Greek yogurt, cottage cheese, or a protein smoothie can add 20–30 g before midday.
Frequently Asked Questions
Can eating too much protein damage my kidneys?
In healthy adults without pre-existing kidney disease, current evidence does not support the claim that high protein intake — up to 2.2 g/kg per day — causes kidney damage. The concern is clinically relevant only for individuals with diagnosed chronic kidney disease (CKD), for whom dietary protein should be managed under medical supervision. If you have kidney disease or a family history of it, discuss specific protein targets with your doctor before making changes.
Do I need protein supplements to meet my daily target?
No. Whole food sources — chicken, fish, eggs, dairy, legumes, tofu — can fully meet protein requirements for most people. Protein powders offer convenience when whole foods are impractical (post-workout, travelling, time-poor mornings), but they provide no physiological advantage over equivalent protein from food. Total daily intake matters more than the form the protein takes.
Is plant protein as effective as animal protein for muscle building?
Plant proteins are often lower in leucine — the amino acid most directly responsible for stimulating muscle protein synthesis — and some are incomplete, lacking one or more essential amino acids. However, a varied plant-based diet combining different protein sources (legumes, grains, soy, nuts) can support muscle building, particularly when total protein intake is toward the upper end of the recommended range. Soy protein has a leucine content and anabolic effect comparable to whey in most studies.
Does the timing of protein intake matter?
Distributing protein across three to four meals matters more than precise timing around workouts. Total daily intake is the primary driver of outcomes. The post-exercise window is somewhat flexible — consuming adequate protein within two to three hours of resistance training is generally sufficient. Consuming most of your daily protein in a single meal results in less efficient utilisation, particularly for muscle protein synthesis.
- World Health Organization, Food and Agriculture Organization, & United Nations University. (2007). Protein and amino acid requirements in human nutrition (WHO Technical Report Series, No. 935). World Health Organization.
- Morton, R. W., Murphy, K. T., McKellar, S. R., Schoenfeld, B. J., Henselmans, M., Helms, E., Aragon, A. A., Devries, M. C., Banfield, L., Krieger, J. W., & Phillips, S. M. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine, 52(6), 376–384.
- Weigle, D. S., Breen, P. A., Matthys, C. C., Callahan, H. S., Meeuws, K. E., Burden, V. R., & Purnell, J. Q. (2005). A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations. American Journal of Clinical Nutrition, 82(1), 41–48.
- Paddon-Jones, D., Westman, E., Mattes, R. D., Wolfe, R. R., Astrup, A., & Westerterp-Plantenga, M. (2008). Protein, weight management, and satiety. American Journal of Clinical Nutrition, 87(5), 1558S–1561S.
- Bauer, J., Biolo, G., Cederholm, T., Cesari, M., Cruz-Jentoft, A. J., Morley, J. E., Phillips, S., Sieber, C., Stehle, P., Teta, D., Visvanathan, R., Volpi, E., & Boirie, Y. (2013). Evidence-based recommendations for optimal dietary protein intake in older people: A position paper from the PROT-AGE Study Group. Journal of the American Medical Directors Association, 14(8), 542–559.
- Helms, E. R., Aragon, A. A., & Fitschen, P. J. (2014). Evidence-based recommendations for natural bodybuilding contest preparation: Nutrition and supplementation. Journal of the International Society of Sports Nutrition, 11, 20.
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- Phillips, S. M. (2012). Dietary protein requirements and adaptive advantages in athletes. British Journal of Nutrition, 108(Suppl 2), S158–S167.