Everyones needs will be different. Your individual needs will depend on your goals, health, body composition, and level of physical activity (type, intensity, and duration). And even taking all this into account, you’ll end up with a starting number, which you’ll need to adjust through testing your self with different amounts.
Daily requirements are in ‘grams’ of protein, either per kilogram of body weight (g/kg) or per pound of body weight (g/lb).
If you’re of healthy weight and sedentary, aim for 1.2–1.8 g/kg (0.54–0.82 g/lb).
If you’re overweight or obese, aim for 1.2–1.5 g/kg (0.54–0.68 g/lb).
If you’re of healthy weight, active, and wish to keep your weight, aim for 1.4–2.2 g/kg (0.64–1.00 g/lb). Try for the higher end of this range, as tolerated, especially if you’re an athlete.
If you’re of healthy weight, active, and wish to build muscle, aim for 1.4–3.3 g/kg (0.64–1.50 g/lb). Eating more than 2.6 g/kg (1.18 g/lb) is probably not going to lead to greater muscle gains, but it can minimize fat gains when “bulking” — i.e., when eating above maintenance in order to gain (muscle) weight.
If you’re of healthy weight, active, and wish to lose fat, aim for 2.2–3.3 g/kg (1.00-1.50 g/lb), skewing toward the higher end of this range as you become leaner or if you increase your caloric deficit (hypocaloric diet).
If you’re pregnant, aim for 1.66–1.77 g/kg (0.75–0.80 g/lb)
Also, don’t forget that …
Protein intake should be based on body weight, not on caloric intake. (But caloric intake should be based on body weight, too, so the two intakes are linked.)
If you are obese, you do not need to try to figure out your ideal body weight or your lean mass (i.e., fat-free mass). Most studies on people with obesity report their findings based on total body weight.
Most studies have looked at dosages up to 1.5 g/kg; only a few have looked at dosages as high as 2.2–3.3 g/kg. However, even those higher dosages don’t seem to have negative effects in healthy people.
Optimal daily protein intake for athletes and similarly active adults
If you’re physically very active, you need more protein daily than if you were sedentary. The American College of Sports Medicine, the Academy of Nutrition and Dietetics, and the Dietitians of Canada recommend 1.2–2.0 g/kg to optimize recovery from training and to promote the growth and maintenance of lean mass when caloric intake is sufficient. This recommendation is similar to that of the International Society of Sports Nutrition (1.4–2.0 g/kg).
Importantly, it may be better to aim for the higher end of the above ranges. According to the most comprehensive meta-analysis to date on the effects of protein supplementation on muscle mass and strength, the average amount of protein required to maximize lean mass is about 1.6 g/kg, and some people need upwards of 2.2 g/kg. For those interested in a comprehensive breakdown of this study, please refer to our Examine.com Research Digest, Issue 34, Volume 1.
However, only 4 of the 49 included studies were conducted in people with resistance training experience (the other 45 were in newbies). There’s some evidence that female athletes require 1.4–1.7 g/kg, and that amateur bodybuilders require 1.7–2.2 g/kg on their non-training days. Since higher protein intakes don’t seem to have negative effects in healthy people, one may want to err toward the higher amounts.
Protein intake for athletes and similarly active adults
Optimal daily protein intake for muscle gain
Resistance training (such as lifting weights) is of course required for muscle gain: you can’t just feed your muscles what they need to grow; you also need to give them a reason to grow.
Assuming progressive resistance overload and a mild hypercaloric diet (370–800 kcal above maintenance), a few studies suggest you’ll gain less fat if you eat more protein (3.3 g/kg rather than 1.8–2.6 g/kg).
What’s important to understand is that a daily protein intake of 3.3 g/kg isn’t likely to help you build more muscle than a daily protein intake of 1.8–2.6 g/kg. What the higher number can do is help you minimize the fat gains you’ll most likely experience if you eat above maintenance in order to gain (muscle) weight.
Daily protein intake for muscle gain
Optimal daily protein intake for fat loss
More protein helps preserve lean mass in dieters, especially lean dieters. An early review concluded that, to optimize body composition, dieting athletes should consume 1.8–2.7 g/kg. Later studies have argued that, to minimize lean-mass loss, dieting athletes should consume 2.3–3.1 g/kg (closer to the higher end of the range as leanness and caloric deficit increase). This latter recommendation has been upheld by the International Society of Sports Nutrition and by a review article on bodybuilding contest preparation.
Note that those recommendations are for people who are relatively lean already. Several meta-analyses involving people with overweightness or obesity suggest that 1.2–1.5 g/kg is an appropriate daily protein intake range to maximize fat loss. This range is supported by the European Association for the Study of Obesity, who recommend up to 1.5 g/kg for elderly adults with obesity. It’s important to realize that this range is based on actual body weight, not on lean mass or ideal body weight.
Considering the health risks associated with overweightness and obesity, it is also noteworthy that eating a diet higher in protein (27% vs. 18% of calories) significantly reduces several cardiometabolic risk factors, including waist circumference, blood pressure, triglycerides, and fasting insulin, while also increasing HDL-C and satiety. These effects are small, however, and likely dependent on the amount of body fat one loses.