How Much Protein Do I Need Daily?

Why Protein Matters

Protein is the structural and functional currency of the human body. Every cell, enzyme, hormone, antibody, and contractile unit of muscle tissue is built from amino acids — the molecular building blocks released when dietary protein is digested. Unlike carbohydrate and fat, which can be stored in meaningful quantities as glycogen and adipose tissue respectively, the body has no dedicated amino acid reservoir; protein must be consumed regularly to maintain the continuous processes of tissue synthesis and repair that underpin not just athletic performance but basic health, immune function, and recovery from injury or surgery.

In musculoskeletal rehabilitation, dietary protein occupies a position of particular importance. The synthesis of new collagen — the structural protein making up tendons, ligaments, fascia, cartilage, and scar tissue — is directly rate-limited by the availability of specific amino acids, particularly glycine, proline, and hydroxyproline. Muscle protein synthesis — the process by which muscle fibres repair micro-damage from exercise and grow stronger — requires an adequate supply of all essential amino acids, with leucine playing a particularly significant signalling role. Inadequate dietary protein while undergoing rehabilitation is, in a very literal biochemical sense, asking the body to rebuild without sufficient building material.

The RDA Is a Minimum, Not an Optimum

The most widely cited protein recommendation — the RDA of 0.8 grams per kilogram of body weight per day — is frequently misunderstood as the optimal intake for health and recovery. It is not. The RDA represents the minimum intake estimated to prevent deficiency in approximately 97.5% of the sedentary population — it is a floor, not a target. For physically active people, older adults, those recovering from musculoskeletal injury, and those engaged in resistance training or rehabilitation, the research evidence clearly and consistently supports considerably higher intakes. A 70 kg sedentary adult consuming the RDA takes in 56 grams of protein daily; the evidence-supported optimal range for an active 70 kg adult would be 112–154 grams daily — nearly double to nearly triple the RDA. Equating the two is one of the most common and consequential nutritional misconceptions in clinical practice.

Requirements for Active and Recovering Individuals

Current evidence synthesis from sports nutrition research supports the following protein intakes by population: Sedentary adults: 0.8–1.0 g/kg/day. Recreationally active adults: 1.2–1.6 g/kg/day to support muscle protein synthesis and recovery. Adults engaged in resistance training: 1.6–2.2 g/kg/day for optimising muscle hypertrophy and recovery — Morton et al.'s (2018) systematic review found no further benefit to muscle mass gains above approximately 1.62 g/kg/day in trained individuals, though individual variation warrants the wider range. Individuals recovering from musculoskeletal injury or surgery: 1.6–2.2 g/kg/day or higher, to support tissue repair and the preservation of muscle mass during enforced reduction in activity. Adults over 65: 1.2–1.6 g/kg/day as a minimum, with evidence supporting higher intakes to counteract the anabolic resistance that characterises skeletal muscle ageing.

Distribution and Meal Timing

Total daily protein intake matters most — but how that protein is distributed across meals also influences the efficiency of its use for tissue synthesis. Research by Witard et al. (2014) and Moore et al. (2009) established that muscle protein synthesis is maximally stimulated by doses of approximately 20–40 grams of high-quality protein per meal, with the response plateauing above this range in most individuals. Consuming the majority of daily protein in a single large meal is therefore less effective for tissue synthesis than distributing the same total across three to five meals throughout the day. Practical application means aiming for a protein-containing meal or substantial snack approximately every three to four hours, with each serving delivering 25–40 grams of high-quality protein.

Protein Sources and Bioavailability

Not all protein sources are equivalent in their ability to support tissue synthesis. Protein quality reflects both the amino acid profile of the source and the digestibility and bioavailability of those amino acids once consumed. Animal-sourced proteins — lean meats, poultry, fish, eggs, and dairy — are complete proteins providing all essential amino acids in proportions well-suited to human tissue synthesis and are typically highly bioavailable. Whey protein (derived from dairy) has among the highest leucine content and fastest digestion rate of common protein sources, making it effective for post-exercise muscle protein synthesis support. Plant-sourced proteins — legumes, lentils, soy, quinoa, tofu, tempeh, and seeds — can fully meet protein needs but typically require greater attention to source combination and total quantity to ensure adequate essential amino acid coverage. Plant-based individuals need to consume somewhat higher total protein quantities to account for generally lower bioavailability.

Preventing Muscle Loss with Age

Sarcopenia — the progressive, age-related loss of skeletal muscle mass and function — begins subtly in the fourth decade and accelerates significantly after 60. It is associated with increased risk of falls and fractures, reduced functional capacity, and poorer recovery from illness, surgery, and musculoskeletal injury. Adequate dietary protein, combined with resistance exercise, is the most evidence-supported intervention for attenuating sarcopenia. Older adults exhibit anabolic resistance — a reduced muscle protein synthetic response to any given dose of amino acids compared to younger adults — meaning higher protein intakes are needed to achieve the same stimulation of muscle maintenance.

Putting It Into Practice

Meeting evidence-supported protein targets is achievable without elaborate supplementation. Some practical reference points: a 150g chicken breast provides approximately 45g protein; 200g of tinned salmon approximately 40g; two large eggs approximately 12g; a 200g serving of Greek yoghurt approximately 18–20g; 200g of firm tofu approximately 16g; 150g of cooked lentils approximately 13g. For most people aiming for 1.6–2.0 g/kg/day, the practical challenge is less about finding exotic food sources and more about consistently including a meaningful protein source in each meal — a habit that, once established, becomes automatic rather than burdensome.