Protein is the most important macronutrient for body composition — and the one most people consistently under-eat. Whether your goal is weight loss, building muscle, improving athletic performance, or simply staying healthy as you age, getting enough protein is not optional. It is the single dietary variable with the most consistent and strongest evidence behind it across nearly every health outcome.
Yet most people have no idea how much protein they actually need, where the official guidelines come from, or why those guidelines are frequently too low for active people. This guide covers everything: the science of protein requirements, how your goal changes your target, the best food sources, and how to hit your numbers without resorting to endless protein shakes.
Before diving into targets, it helps to understand why protein is so important. Unlike carbohydrates and fat — which are primarily energy sources — protein is a structural macronutrient. Every cell in your body contains protein, and many of the most critical biological processes depend on it:
The widely cited official recommendation for protein intake is 0.8g per kg of body weight per day (or approximately 0.36g per pound). For a 70 kg person, this equals 56g of protein daily.
The critical context that most sources omit: this figure represents the minimum needed to prevent deficiency in sedentary adults — not the optimal amount for health, performance, body composition, or healthy ageing. It was established to prevent muscle wasting in the least active segment of the population, not to help active people thrive.
For generally healthy, moderately active adults who are not trying to lose weight or build muscle, 1.2–1.6g per kg of body weight per day is the evidence-supported target. A 2017 meta-analysis in the British Journal of Nutrition covering 185 studies concluded that this range supports lean mass maintenance, healthy metabolic function, and bone density throughout adulthood.
If you are in a calorie deficit to lose body fat, protein requirements increase significantly. During a calorie deficit, the body faces pressure to break down muscle tissue for energy — a process called catabolism. Higher protein intake is the primary defence against this muscle loss, ensuring that the weight you lose is predominantly fat rather than a mix of fat and muscle.
The evidence-based target for weight loss is 1.6–2.2g per kg of body weight per day. A landmark 2016 study by Longland et al. in the American Journal of Clinical Nutrition found that participants consuming 2.4g/kg during a calorie deficit gained muscle and lost fat simultaneously — demonstrating that very high protein intake can achieve body recomposition even without a calorie surplus.
For people engaged in regular resistance training with the goal of building muscle, the research consensus points to 1.6–2.2g per kg per day as the optimal range. A comprehensive 2018 meta-analysis by Morton et al. in the British Journal of Sports Medicine — covering 49 studies and 1,800 participants — found that protein supplementation above 1.62g/kg produced no additional muscle gains in trained individuals, suggesting this as a practical upper target for most people.
The distribution of protein across meals also matters for muscle building. Research shows that spreading protein across 3–5 meals of 25–40g each maximises muscle protein synthesis throughout the day, compared to consuming most protein in one or two large meals.
Protein requirements increase with age due to a phenomenon called anabolic resistance — older muscle tissue becomes less responsive to protein, requiring higher doses to produce the same muscle-building signal. A growing body of evidence, including a 2019 consensus statement from the PROT-AGE Study Group, recommends 1.0–1.2g per kg as a minimum for healthy older adults, rising to 1.2–1.6g per kg for those who are active or at risk of sarcopenia (age-related muscle loss).
Sarcopenia affects an estimated 10–20% of adults over 65 and is associated with increased fall risk, reduced independence, and higher mortality. Adequate protein intake is one of the most effective and evidence-supported strategies for prevention.
Use our free food diary to log your meals and see exactly how much protein you're eating — and where the gaps are.
Open Food Diary →| Goal | Recommended Intake | Example: 70kg person |
|---|---|---|
| General health, sedentary | 0.8–1.2g/kg/day | 56–84g/day |
| General health, active | 1.2–1.6g/kg/day | 84–112g/day |
| Weight loss (calorie deficit) | 1.6–2.2g/kg/day | 112–154g/day |
| Muscle building (resistance training) | 1.6–2.2g/kg/day | 112–154g/day |
| Older adults (65+) | 1.0–1.6g/kg/day | 70–112g/day |
| Endurance athletes | 1.4–1.7g/kg/day | 98–119g/day |
Understanding your protein target in grams is one thing; knowing which foods to eat to hit it is another. Here are the most protein-dense foods ranked by protein content, along with their calorie cost:
| Food | Protein per 100g | Calories per 100g | Notes |
|---|---|---|---|
| Chicken breast (cooked) | 31g | 165 kcal | Leanest mainstream protein source |
| Canned tuna (in water) | 25g | 110 kcal | Affordable, zero prep |
| Turkey breast | 29g | 135 kcal | Similar to chicken, slightly lower fat |
| Cottage cheese (low fat) | 11g | 72 kcal | Slow-digesting casein; ideal before bed |
| Greek yogurt (0% fat) | 10g | 57 kcal | Versatile; good probiotic source |
| Eggs (whole) | 13g per 2 eggs | 140 kcal per 2 eggs | Complete amino acid profile |
| Salmon (Atlantic, cooked) | 25g | 208 kcal | High in omega-3; excellent overall nutrition |
| Lean beef mince (90%) | 26g | 176 kcal | High in iron and zinc |
| Edamame | 11g | 121 kcal | Best plant protein per serving |
| Lentils (cooked) | 9g | 116 kcal | High fibre; good iron source |
| Tofu (firm) | 8g | 76 kcal | Complete protein; very versatile |
| Whey protein powder | 24g per scoop | 120 kcal per scoop | Fast-absorbing; ideal post-workout |
Animal proteins (meat, fish, eggs, dairy) are considered "complete" proteins because they contain all nine essential amino acids in proportions that closely match human needs. Plant proteins are often "incomplete" — they contain all essential amino acids but in imbalanced ratios, with one or more amino acids present in insufficient quantities to maximise muscle protein synthesis.
This does not mean plant proteins are inferior — it means plant-based eaters need to pay more attention to variety and overall quantity. Combining different plant protein sources throughout the day (legumes with grains, for example) provides a full complement of essential amino acids. Soy protein and pea protein are exceptions: both are complete proteins and have been shown in studies to support muscle building comparably to whey protein when consumed in equivalent amounts.
The practical recommendation for plant-based eaters: aim for the higher end of the protein range (2.0–2.2g/kg) to account for the slightly lower bioavailability and digestibility of most plant proteins compared to animal sources.
For many people, the challenge is not understanding the target — it is hitting it consistently. Here is what a practical high-protein day looks like for a 70 kg person targeting 140g of protein:
Total: approximately 140g protein across roughly 1,600 calories — leaving room for additional carbohydrates and fats to complete daily calorie needs.
Among the three macronutrients — protein, carbohydrates, and fat — protein consistently produces the greatest satiety per calorie. This is not simply a subjective experience: it is driven by distinct physiological mechanisms that make protein uniquely effective at reducing overall calorie intake, which is a primary reason high-protein dietary approaches are so consistently effective for weight management.
The satiety effects of protein operate through multiple pathways. First, protein consumption stimulates the release of several appetite-suppressing hormones, including peptide YY (PYY), glucagon-like peptide-1 (GLP-1), and cholecystokinin (CCK), while simultaneously suppressing ghrelin (the primary hunger hormone). Second, protein has the highest thermic effect of feeding of any macronutrient — approximately 20–30% of protein calories are expended in the process of digesting and metabolising protein, compared to 5–10% for carbohydrates and 0–3% for fat. This means a 400-calorie protein source effectively contributes only 280–320 net calories after accounting for the energy cost of processing it.
Third, adequate protein intake supports stable blood glucose levels by reducing the glycaemic impact of meals — protein slows gastric emptying and reduces the rate of carbohydrate absorption, producing a more gradual postprandial glucose curve and less pronounced hunger rebound. The combination of these mechanisms explains why research consistently shows that people who increase protein intake eat less total food and report greater satisfaction on higher-protein diets.
The question of protein timing — whether it matters when during the day protein is consumed, not just how much total protein is eaten — has been extensively researched in the context of both muscle building and weight management. The findings are nuanced and practically important.
Early sports nutrition research promoted the concept of a narrow "anabolic window" — a 30–60 minute period immediately after exercise during which protein consumption was essential for maximising muscle protein synthesis. Subsequent research has substantially revised this view. A 2013 meta-analysis by Schoenfeld and Aragon in the Journal of the International Society of Sports Nutrition found that the total daily protein intake was a far stronger determinant of muscle protein synthesis outcomes than the precise timing of protein relative to exercise. The practical anabolic window appears to extend to approximately 3–5 hours after training in most people.
This does not mean post-workout protein is irrelevant — consuming protein within a few hours of training is beneficial and practical. It means that the urgency of an immediate post-workout protein shake has been overstated, and that missing the first 30 minutes after exercise does not meaningfully impair results when daily protein targets are met.
One protein timing consideration with growing research support is pre-sleep protein consumption. A 2012 study by Res et al. in Medicine & Science in Sports & Exercise found that consuming 40g of casein protein before sleep significantly increased overnight muscle protein synthesis compared to placebo. The slow digestion of casein protein provides a sustained amino acid supply during the overnight fasting period — the longest daily fast most people experience. For individuals focused on maximising muscle retention during a calorie deficit, a pre-sleep protein serving (cottage cheese, Greek yoghurt, casein protein powder) may be worth incorporating.
Research on protein distribution suggests that spreading protein intake relatively evenly across meals — rather than consuming the majority at dinner — is more effective for maximising muscle protein synthesis over 24 hours. A 2014 study by Areta et al. in the Journal of Physiology found that muscle protein synthesis was significantly higher when 80g of daily protein was consumed in four equal 20g servings compared to a skewed distribution of 10g, 10g, 60g across three meals. Practically, this means aiming for a minimum of 20–30g of protein per meal — the threshold that appears to maximally stimulate acute muscle protein synthesis — rather than saving most protein for the evening meal.
The debate between plant and animal protein sources is frequently oversimplified in popular nutrition discourse. A nuanced understanding of the differences allows for informed dietary choices that align with both health goals and personal values.
Animal proteins (meat, fish, eggs, dairy) are generally more digestible than plant proteins, with digestibility scores typically above 90%. Most plant proteins have lower digestibility — soy protein is approximately 91% digestible, comparable to animal sources; legume proteins are 70–80% digestible; wheat protein is approximately 50–75% digestible. The Digestible Indispensable Amino Acid Score (DIAAS) — the current gold standard for measuring protein quality — consistently rates animal proteins above most plant proteins.
However, this difference can be substantially addressed through: combining complementary plant proteins (grains + legumes provide a complete amino acid profile); processing techniques that increase digestibility (sprouting, fermenting, cooking); and consuming slightly higher total protein when relying primarily on plant sources (targeting the upper end of the recommended range: 2.0g per kg body weight rather than 1.6g).
Leucine is the branched-chain amino acid (BCAA) most responsible for triggering muscle protein synthesis — specifically, for activating the mTOR signalling pathway that initiates the muscle-building response. Animal proteins generally contain higher leucine concentrations than plant proteins. Whey protein is particularly leucine-rich at approximately 10–11% leucine by weight; chicken breast contains approximately 8%; most legumes contain 6–8%; wheat protein contains approximately 6.5%.
For muscle building and preservation purposes, the leucine content of protein sources matters. Plant-based athletes and those relying heavily on plant proteins may benefit from prioritising higher-leucine plant sources (soy, hemp, peas) or supplementing with leucine or BCAAs to ensure the muscle protein synthesis threshold is reliably crossed at each meal.
Understanding protein targets and sources is useful; translating them into daily meals that are practical, affordable, and enjoyable is where most people need support. The following strategies make high-protein eating sustainable in real-world conditions.
The most common barrier to consistent high-protein eating is convenience: when hunger strikes and no protein-rich food is immediately available, lower-protein choices fill the gap by default. Batch cooking resolves this by ensuring protein sources are always on hand. Practical batch cooking approaches include: cooking a week's worth of chicken breast, hard-boiling a dozen eggs, preparing a large pot of lentil soup, or cooking ground turkey in bulk. These prepared proteins can be assembled into meals in minutes, removing the friction of protein-rich eating on busy days.
Building meals around protein sources — rather than treating protein as a side component of a carbohydrate-centred plate — consistently produces higher protein intake without deliberate tracking. The practical approach is to select your protein source first when planning or preparing a meal, then add vegetables and starch around it. A chicken breast + vegetables + rice plate naturally contains more protein than a pasta dish with a small amount of chicken added. This simple cognitive reframe — protein as the anchor, not the addition — meaningfully shifts dietary patterns without requiring calorie counting or detailed planning.
Replacing conventional low-protein snacks (crisps, biscuits, crackers) with protein-rich alternatives is one of the highest-impact single changes available for increasing daily protein intake. Practical protein-rich snacks that require no preparation include: Greek yoghurt (15–20g protein per 200g serving), cottage cheese (14g per 100g), hard-boiled eggs (6g each), string cheese (7g per stick), edamame (8g per 100g), and protein bars (15–25g per bar). Keeping one or two of these options consistently stocked removes the moment-of-hunger decisions that lead to low-protein choices.
The concern that high protein intake damages kidneys is one of the most persistent myths in nutrition science. This concern originated from observations of patients who already had kidney disease, in whom excess protein does worsen kidney function. In healthy individuals with normal kidney function, there is no credible evidence that high protein intake causes kidney damage.
A 2016 review in the Journal of Nutrition and Metabolism examined studies of protein intakes up to 4.4g/kg per day in healthy athletes and found no adverse health effects. The authors concluded that protein intakes as high as 3g/kg per day are safe for healthy adults over periods of at least one year.
The practical upper limit from a health perspective is therefore not a concern for the vast majority of people. The more realistic concern for most people is eating too little protein rather than too much.
Protein timing is a real but secondary consideration compared to total daily intake. The research hierarchy is clear: total daily protein is the primary driver of outcomes; distribution across meals is a secondary optimisation.
That said, the evidence does support a few practical timing guidelines: