How Much Protein Do You Actually Need?

How much protein do I need per day?

The UK Reference Nutrient Intake sets protein at 0.75g per kilogram of body weight per day, roughly equivalent to the global RDA of 0.8g/kg/day. These figures represent the minimum to prevent deficiency in sedentary adults, not the amount that optimises body composition, recovery, or long-term muscle health.

Research increasingly supports higher intakes. The International Society of Sports Nutrition recommends 1.4-2.0g/kg/day for active individuals, while a 2022 meta-analysis of 74 randomised controlled trials found that the lean body mass benefit of increased protein becomes significant at intakes of 1.6g/kg/day or above in adults under 65.

As a practical starting point: sedentary adults should aim for 1.0-1.2g/kg, moderately active adults for 1.2-1.4g/kg, and those training regularly for 1.6-2.0g/kg. Use the calculator above to get a personalised recommendation based on your specific weight and goals.

How much protein should I eat to build muscle?

A landmark meta-analysis by Morton et al. (2018) analysed 49 studies with 1,863 participants and found that 1.6g/kg/day is the threshold at which additional protein no longer produces significant gains in fat-free mass when combined with resistance training. Most sports nutrition bodies recommend a range of 1.6-2.2g/kg/day for hypertrophy.

Distribution matters as much as total intake. Aim for approximately 25-30g of high-quality protein per meal spread across 3-5 eating occasions. Intakes above 40g in a single sitting do not appear to offer additional muscle-building benefit. Consuming protein before sleep has also been shown to increase overnight muscle protein synthesis.

How much protein is too much?

Long-term consumption of up to 2.0g/kg/day is safe for healthy adults, with a tolerable upper limit of approximately 3.5g/kg/day in well-adapted individuals. Chronic intake exceeding 2.0g/kg/day may carry risks for digestive, renal, and vascular health. Individuals with pre-existing kidney disease should consult a healthcare professional before significantly increasing protein intake.

For context, an 80kg person consuming 2.0g/kg would eat 160g of protein per day, which is achievable through a combination of whole foods and supplementation. The vast majority of people are far more likely to be eating too little protein than too much.

Is my protein intake enough?

Here is a simple way to check: if you weigh 80kg and eat 64g of protein per day, you are technically meeting the RDA minimum of 0.8g/kg. But you are likely falling short of optimal, especially if you exercise, are over 50, or are trying to lose weight while preserving muscle.

Signs that your protein intake may be insufficient include: slow recovery from workouts, gradual loss of muscle mass or strength, frequent hunger between meals, poor wound healing, and thinning hair or brittle nails. If you are in a caloric deficit, higher protein intake (1.2-1.6g/kg) is particularly important to prevent lean mass loss.

Track your intake for a few days using the calculator above, then compare it against your recommended range. Most people are surprised by how much protein they actually need compared to what they habitually eat.

What is the ideal protein intake?

There is no single ideal number. The optimal intake depends on your age, activity level, goals, and dietary pattern. Here is a quick reference based on published research:

Plant-based eaters should aim for the higher end of their range. The ISSN recommends that vegans consume 10-20% more total protein to compensate for the lower digestibility and leucine content of plant proteins. Blended sources such as pea and rice protein together provide a more complete amino acid profile.

Protein intake on GLP-1 medication (Mounjaro, Ozempic, Wegovy)

GLP-1 receptor agonists deliver substantial weight loss, but up to 25-40% of weight lost can come from lean mass including muscle. The appetite-suppressing effect of these medications, with some studies reporting energy intake reductions of up to 39%, means protein is often the first macronutrient to fall short.

The emerging clinical consensus recommends at least 1.2g/kg/day for GLP-1 users, with active individuals aiming for 1.2-2.0g/kg/day. A 2025 study of 200 adults on semaglutide or tirzepatide found that those combining resistance training with adequate protein intake lost approximately 13% of body weight but only 3% of muscle mass, a substantially better ratio than the clinical trials where exercise was not mandated.

For a full guide, see our best protein powder for GLP-1 users article.