How Much Protein Do You Really Need Per Day?

Few nutrition questions generate as much confusion as "how much protein should I eat?" Recommendations range from the modest government minimum to the much higher figures quoted in gyms. Both can be correct, because they answer different questions. This guide lays out evidence-based targets for different goals.

The baseline: preventing deficiency

The Recommended Dietary Allowance (RDA) for protein is 0.8 g per kilogram of bodyweight per day for healthy adults. It is important to understand what this number represents: it is the amount estimated to meet the needs of most sedentary people and prevent deficiency. It is a floor, not an optimum, and it was never intended to define the intake that best supports muscle, strength or healthy ageing.

For an 80 kg adult, the RDA works out to about 64 g of protein per day, an amount most people in developed countries already exceed.

For building muscle and strength

If your goal is to gain or maintain muscle while training, the evidence supports substantially more. The 2017 ISSN position stand recommends roughly 1.4 to 2.0 g/kg/day for physically active people. The influential Morton meta-analysis identified a practical sweet spot: benefits for muscle plateaued at around 1.6 g/kg/day, with the study's upper confidence limit near 2.2 g/kg/day.

For most trainees, aiming for around 1.6 g/kg/day is a sensible, well-supported target. Going higher is not harmful for healthy people but tends to offer diminishing returns for muscle specifically.

For fat loss

When you are in a calorie deficit, protein needs actually rise rather than fall. Higher protein helps preserve lean muscle while you lose fat, and it supports appetite control. Research in lean, training individuals during aggressive dieting suggests intakes toward the 1.8 to 2.7 g/kg/day range help protect muscle. For most people dieting moderately, roughly 1.6 to 2.4 g/kg is a practical range.

For older adults

Ageing brings anabolic resistance: muscles respond less efficiently to protein, and older adults are at higher risk of losing muscle (sarcopenia). Expert groups such as the PROT-AGE study group recommend higher intakes for older people, in the region of 1.0 to 1.2 g/kg/day for healthy seniors and up to 1.2-1.5 g/kg/day for those who are ill or very active. Meeting a slightly higher per-meal protein dose also matters more with age.

Does distribution across the day matter?

Total daily protein is the priority, but how you spread it has a secondary effect. Muscle protein synthesis responds to a meaningful dose of protein per meal, and research suggests distributing intake across three to four meals of roughly 0.4 g/kg each is more effective for muscle than skewing most of your protein into a single meal. In practice, that means aiming for a solid protein source at each main meal rather than backloading it all at dinner.

Is high protein safe?

For healthy people with normal kidney function, higher-protein diets within these ranges have a strong safety record and do not damage the kidneys or bones, contrary to older myths. In fact, adequate protein is protective for bone when calcium intake is sufficient. People with pre-existing kidney disease are an exception and should follow medical advice. As with any dietary change, individual circumstances matter, and those with medical conditions should consult a professional.

Translating grams into food

Targets in grams per kilogram can feel abstract, so it helps to anchor them to real portions. As a rough guide, a palm-sized serving of cooked chicken, fish or lean meat provides around 25-30 g of protein; a large egg about 6 g; a cup of Greek yoghurt around 15-20 g; a cup of cooked lentils about 18 g; and a typical scoop of protein powder 20-25 g. An 80 kg person aiming for 1.6 g/kg needs roughly 128 g per day, which might look like three main meals of 30-40 g plus a snack. Framed this way, the targets are usually more achievable than they first appear.

Two practical hurdles are common. People trying to build muscle often underestimate how much they eat and fall short of their target, while those simply maintaining health often already meet their needs without effort. Tracking intake for a few days is a useful reality check before assuming you need to eat dramatically more or reach for supplements.

A quick reference

• Sedentary, general health: around 0.8-1.2 g/kg/day.
• Building muscle: around 1.6 g/kg/day, up to about 2.2.
• Fat loss while training: around 1.6-2.4 g/kg/day.
• Older adults: around 1.0-1.2 g/kg/day, higher if very active.

Key takeaways

• The 0.8 g/kg RDA prevents deficiency but is not optimal for muscle or ageing.
• Around 1.6 g/kg/day is a well-supported target for building muscle.
• Protein needs rise, not fall, during fat loss and with older age.
• Spreading protein across three to four meals beats concentrating it in one.
• Higher protein is safe for healthy kidneys; those with kidney disease need medical guidance.

References

1. Morton et al., protein supplementation meta-analysis — British Journal of Sports Medicine, 2018
2. Jäger et al., ISSN Position Stand: Protein and Exercise — Journal of the International Society of Sports Nutrition, 2017
3. Bauer et al., PROT-AGE Study Group recommendations for older adults — Journal of the American Medical Directors Association, 2013
4. Institute of Medicine, Dietary Reference Intakes for Protein (RDA 0.8 g/kg) — National Academies Press, 2005
5. Helms et al., protein intake for lean athletes during caloric restriction — International Journal of Sport Nutrition and Exercise Metabolism, 2014