Weight lifters need up to 1.8
grams per kilogram
per day, while endurance athletes require up to 1.4
grams of protein per kilogram of body weight.
Multiply your daily caloric intake by 0.15 or 0.2 to estimate how many of your calories should come from protein. For example, if you eat 2,500 calories daily, you should get between 375 and 500 calories from protein.
If you tire easily, you may not get enough protein.