Daily Protein Requirement Calculator

Why Protein Needs Rise With Age?

Most adults need between 0.8g and 2.0g of protein per kilogram of body weight daily, depending on activity level, age, and goals. The 0.8g/kg figure is the minimum reference nutrient intake (RNI) for sedentary adults — enough to prevent deficiency, not enough to support muscle building or active recovery. The UK's SACN and the International Society of Sports Nutrition both recommend higher intakes for active adults: 1.4-2.0g/kg for resistance training, 1.2-1.6g/kg for endurance training. As people age, protein synthesis becomes less efficient — older adults (65+) need around 1.2-1.6g/kg to maintain muscle mass, even without exercise, because age-related muscle loss (sarcopenia) accelerates when protein is low. Most UK adults consume roughly 60-75g per day, which falls short for anyone exercising regularly or over 60.

What do I need to know about Protein Timing?

When you eat protein matters as well as how much. Muscle protein synthesis peaks within 2-3 hours of a stimulus (exercise or food) and the effect of a single meal plateaus at around 40g of protein — eating 80g in one sitting doesn't double the benefit over eating 40g. For muscle building and maintenance, spreading intake across 3-4 meals of 20-40g each is more effective than eating the same total in one or two sittings. Post-exercise protein is particularly effective: consuming 20-40g within 2 hours of a resistance session significantly improves muscle protein synthesis compared to having the same amount at a random time. For overnight recovery, a slow-digesting protein source (casein from dairy, or a mixed protein food) before bed can maintain protein synthesis through the night. For everyday health maintenance without specific performance goals, timing matters far less — total daily intake is the primary driver.

What's the key thing to understand about Sources and Quality?

Not all protein sources are equal. Complete proteins — those containing all nine essential amino acids in sufficient quantities — are found in animal products (meat, fish, eggs, dairy) and a small number of plant sources (soy, quinoa, buckwheat). Most plant proteins are incomplete, meaning they lack or are low in one or more essential amino acids. However, eating a varied plant-based diet across the day provides all essential amino acids through complementary combinations — rice and beans, hummus and wholemeal bread, or soy milk with oats. Leucine is the amino acid most strongly associated with triggering muscle protein synthesis, and it's highest in dairy (especially whey protein), eggs, and meat. Plant-based eaters building muscle may benefit from slightly higher total protein intake (10-15% above the standard recommendation) and choosing leucine-rich plant sources where possible (edamame, tofu, lentils, pumpkin seeds). Protein supplements (whey, casein, pea, soy) are no more effective than food protein of equivalent composition — they're convenient, not magical.

When to Seek Medical Advice?

Very high protein intakes (above 3.0g/kg/day) are not necessary for most people and may place excess load on the kidneys — a genuine concern for anyone with pre-existing kidney disease or reduced kidney function. If you have kidney disease, liver disease, or a metabolic disorder, discuss protein targets with a dietitian or your GP before significantly increasing intake. High-protein diets can also reduce dietary variety and fibre if they crowd out plant foods, so balance matters. On the other hand, protein deficiency — while rare in people eating a varied diet in the UK — causes muscle loss, poor wound healing, immune weakness, and fatigue over time. If you are eating very little, following a restrictive diet, or recovering from illness or surgery, a registered dietitian can calculate your specific needs. This calculator gives a general evidence-based estimate — for medical conditions or performance goals, personalised advice from a qualified nutrition professional is always preferable.