Introduction:
Understanding how much protein you need per day is key to supporting your health and fitness goals. For active adults, the optimal protein intake depends on whether you’re simply maintaining muscle, looking to build (hypertrophy), or aiming to lose fat while preserving muscle. Human studies have established recommended protein ranges (in grams of protein per kilogram of body weight, g/kg) for each scenario. Below we break down the science-backed guidelines for daily protein intake, with practical examples for clarity.

Protein Requirements for Maintenance (General Health)

For an average sedentary adult, the minimum recommended protein is 0.8 g/kg of body weight. This amount prevents deficiency but may be insufficient to optimize muscle maintenance in active individuals. Recent research suggests that physically active people benefit from a higher daily protein intake even when not trying to gain muscle. Specifically, experts recommend roughly 1.0–1.2 g/kg for those with light to moderate activity, and around 1.3–1.6 g/kg for very active individuals, to maintain muscle mass and strength. For example, a moderately active 70 kg adult might aim for ~85–105 g of protein per day, compared to about 56 g/day at the basic 0.8 g/kg level. This higher intake supports muscle repair, recovery, and other physiological functions without necessarily increasing muscle size. Notably, long-term studies indicate that consuming up to ~2.0 g/kg daily is safe for healthy adults, so these moderate intake levels are well within safe limits.

• Example: A 70 kg person who exercises a few times a week could target ~84 g of protein daily (1.2 g/kg) for maintenance.

Protein Intake for Muscle Gain (Hypertrophy)

Building new muscle (hypertrophy) requires a higher protein intake combined with resistance training. Research in healthy adults shows that protein intakes around 1.4–2.0 g/kg/day are effective for maximizing muscle protein synthesis and growth when training regularly. In practical terms, aiming for about 1.6 g/kg is a good target for most people focused on muscle gain. This falls in line with the common gym advice of ~1 gram of protein per pound of body weight (2.2 g/kg), although evidence suggests ~1.6 g/kg is sufficient for optimal results. Consuming protein in this range, spread evenly in meals, maximizes muscle protein synthesis after workouts.

• Example: For an 80 kg athlete trying to build muscle, ~128 g of protein per day (at 1.6 g/kg) is often recommended.

Higher Protein for Fat Loss (Muscle Preservation)

When losing weight (caloric deficit), adequate protein is crucial to preserve muscle while shedding fat. Studies on dieting adults report that higher protein intakes (around 1.8–2.4 g/kg) help maintain lean mass during weight loss better than the standard protein RDA. In fact, research has shown that consuming about 2× the RDA (~1.6 g/kg) or more can significantly reduce the amount of muscle lost during a diet compared to the minimum 0.8 g/kg. For example, one trial in young men found that eating 2.4 g/kg of protein in a 40% calorie deficit (along with intense exercise) not only preserved muscle but even led to slight muscle gains, whereas a moderate protein intake (1.2 g/kg) led to essentially no muscle gain.The high-protein group also lost more fat, demonstrating the benefit of upping protein when cutting calories. A target around 2.0–2.4 g/kg will suffice for the majority aiming to lose fat while keeping muscle. This also helps with satiety and increases the thermic effect of food (since protein takes more energy to digest), which can aid fat loss.

• Example: A 70 kg person in a fat-loss phase might raise protein to 140 g/day (2.0 g/kg) or more. In one study, men around this size eating ~168 g protein (2.4 g/kg) during a diet lost nearly 5 kg of fat in 4 weeks while actually gaining muscle mass. Ensuring each meal contains a high-protein food can help reach these higher targets.

Key Takeaways and Daily Protein Targets

In summary, current human research provides clear protein intake recommendations tailored to different goals for healthy adults:

• Active Maintenance: Aim for 1.0–1.2 g/kg daily to maintain muscle and support training – e.g., ~84g for a 70 kg individual. This range covers most recreational athletes’ needs for maintaining physique and recovery.
• Muscle Gain (Hypertrophy): About 1.6 g/kg/day optimizes muscle growth when combined with resistance exercise – e.g., ~112 g for a 70 kg person. Intakes up to ~2.0 g/kg (140 g) are commonly used and fall within recommended ranges. Beyond ~2 g/kg, extra protein is generally not required for muscle-building in most cases.
• Fat Loss (Muscle Preservation): Use the higher end of protein intake, roughly 1.8–2.4 g/kg during caloric deficits – e.g., 125–170 g for a 70 kg person. This helps preserve lean mass; very lean or bodybuilders may go up to ~3 g/kg in short cutting phases. High protein intakes in deficits have been shown to allow fat loss with minimal muscle loss, especially when combined with strength training.

By adjusting your protein intake to your activity level and goal, you can support your body composition and performance effectively. These guidelines, grounded in human studies, can be used by active individuals, athletes, and coaches to plan diets. Remember that total daily protein is just one piece – it’s also important to consume a balanced diet with adequate calories and to distribute protein through the day for best results. With the right protein intake, you’ll be giving your muscles the building blocks they need for maintenance, growth, or preservation during fat loss.

Sources: Wu G., 2016; Jäger R et al., 2017; Morton RW et al., 2018; Pasiakos SM et al., 2013; Longland TM., 2016.