How Much Protein Do You Really Need?

1. What Does Protein Do in Your Body?

Protein is one of the three macronutrients (alongside carbohydrates and fat) and the only one that contains nitrogen. It is the primary building block for muscle tissue, enzymes, hormones, antibodies, and structural components throughout the body.

Unlike carbohydrates and fat, the body has no dedicated storage system for protein. Excess dietary protein is either used for energy or converted to fat — which is why consistent daily intake matters more than occasional large meals.

2. The RDA vs What Research Actually Shows

The official Recommended Dietary Allowance (RDA) for protein is 0.8g per kg of body weight per day. For a 75 kg adult, this equates to 60g of protein daily.

However, the RDA represents the minimum required to prevent deficiency in sedentary adults — it is not the optimal amount for health, body composition, or longevity. A substantial body of research published since 2010 suggests that optimal protein intake is considerably higher:

3. Protein for Muscle Building

Building muscle requires two things: a sufficient training stimulus (resistance exercise) and enough dietary protein to support muscle protein synthesis. Research published in the British Journal of Sports Medicine (Morton et al., 2018) analysed 49 studies and over 1,800 participants, concluding that the upper effective limit for muscle growth is approximately 1.62g of protein per kg of body weight per day.

Protein intakes beyond 2.2g/kg appear to offer no additional muscle-building benefit, though they are not harmful for healthy individuals. Higher intakes are sometimes used during aggressive calorie cutting to minimise muscle loss.

Does Protein Timing Matter?

Spreading protein intake across 3–5 meals is more effective than consuming it in one or two large sittings. Each meal should ideally contain 20–40g of protein to maximise muscle protein synthesis, as there appears to be a ceiling of approximately 30–40g that can be used for muscle building per meal, though this varies with body size and training status.

4. Protein During Fat Loss

When in a calorie deficit, higher protein intake plays a critical role in preserving lean muscle mass. Without adequate protein, the body increasingly turns to muscle as an energy source during weight loss, which reduces metabolic rate and worsens body composition outcomes.

A higher-protein diet during fat loss also offers a significant practical advantage: protein is the most satiating macronutrient. Studies show that increasing protein from 15% to 30% of daily calories reduces spontaneous calorie intake by an average of 441 kcal per day without deliberate restriction.

5. Protein and Healthy Ageing

After the age of 50, the body becomes less efficient at using dietary protein for muscle synthesis — a phenomenon known as anabolic resistance. Older adults require more protein per meal to achieve the same muscle protein synthesis response as younger people.

Sarcopenia (age-related muscle loss) affects an estimated 10–25% of people over 60 and is associated with increased risk of falls, fractures, metabolic disease, and reduced quality of life. Adequate dietary protein, combined with resistance training, is the most effective evidence-based strategy to slow or reverse this process.

The PROT-AGE Study Group recommends that adults over 65 consume at least 1.0–1.2g of protein per kg body weight, rising to 1.2–1.5g in those who are physically active.

6. Best Sources of Dietary Protein

Animal proteins are generally "complete" — they contain all nine essential amino acids in adequate proportions. Most plant proteins are incomplete, though combining different plant sources (e.g. rice and beans) throughout the day provides a complete amino acid profile.

7. Practical Distribution Throughout the Day

If your target is 160g of protein per day, a practical distribution might look like: breakfast with 40g (eggs, Greek yoghurt), a mid-morning snack with 20g (cottage cheese), lunch with 40g (chicken or fish), afternoon with 20g (protein shake), and dinner with 40g (meat, fish, or legumes).

Consistency matters more than perfection. Hitting your daily target most of the time will produce results regardless of whether you nail the exact per-meal distribution.