Protein Intake Calculator

Protein requirements depend on body weight, activity level and training goals. The UK Reference Nutrient Intake (RNI) is 0.75 g per kilogram of body weight per day for sedentary adults, which comes to 52.5 g a day at 70 kg and is set to prevent deficiency rather than to optimise anything. Active individuals and those doing strength training typically need 1.2 to 2.0 g/kg to support muscle repair and growth. Average UK intake sits at 75 to 90 g a day, comfortably above the RNI but often short of a training target.

This calculator takes your weight, one activity or goal setting (sedentary, moderately active, muscle building or endurance) and the number of meals you eat, and produces a daily protein target in grams with a per-meal split. The sedentary setting starts at the UK RNI of 0.75 g/kg. At 70 kg, a general activity target of 1.2 to 1.6 g/kg works out at 84 to 112 g, while building muscle at 1.6 to 2.2 g/kg calls for 112 to 154 g. Older adults are advised to take 1.0 to 1.2 g/kg to slow sarcopenia, the age-related loss of muscle. Pregnancy adds 6 g a day to the RNI and breastfeeding adds 11 g.

The result also divides the daily target evenly across three, four or five meals, since research suggests spreading intake evenly, at 20 to 40 g per meal, maximises muscle protein synthesis. Daily totals still matter more than clock-watching, because synthesis stays raised for 24 to 48 hours after training, but three or four meals of 25 to 40 g beat one large serving. Roughly 3 g of leucine per meal is what triggers the response, which is part of why whey tends to outperform plant proteins for muscle building. Something slow-digesting before bed, cottage cheese or Greek yoghurt, keeps the supply going overnight, and 20 to 40 g within a couple of hours of training is useful without being essential.

Good UK protein sources include chicken breast at about 31 g per 100 g, tinned tuna at about 25 g, eggs at about 6 g each, Greek yoghurt at about 10 g per 100 g and lentils at about 9 g per 100 g cooked. Turkey gives 29 g, beef mince 26 g, salmon 25 g, cottage cheese 12 g, chickpeas 9 g, tofu 8 g and quinoa 4.4 g, with nuts and a scoop of whey powder both landing around 20 to 25 g. Tempeh, hemp seeds and pulses carry most of the load in a vegan diet.

Cost varies more than most people expect. Fifty grams of protein works out at roughly £0.35 from lentils, £0.50 from whey powder, £0.80 from chicken breast and £1.00 from eggs. Quality varies too. Animal proteins are complete, carrying all nine essential amino acids in useful ratios, while plant proteins are usually short of one or two: grains lack lysine, legumes lack methionine. Combining them fixes the gap, whether that is beans with rice, hummus with pita or peanut butter on wholemeal bread. The modern measure, DIAAS, scores whey at 1.18, egg white at 1.16, milk at 1.14, beef at 1.11 and soy at 1.00, against 0.59 for rice and 0.40 for wheat.

Meeting a higher target usually means planning meals around a protein source first rather than adding it as an afterthought. During weight loss the case gets stronger, with protein at 25 to 35% of calories, or 112 to 154 g a day at 70 kg, protecting muscle while you are in deficit. Fall short and 30 to 50% of the weight lost can be muscle, which is the worst version of the result. Protein is also the most filling of the three macronutrients and the most expensive to digest, using 25 to 30% of its own calories in the process against 5 to 10% for carbohydrate and fat. NHS guidance separately asks for two portions of fish a week, one of them oily.