Updated: Oct 7, 2019
According to the USDA, I (a 6'3", 195 pound 'Very Active' male) should get the following:
Carbohydrate: 436 - 630 grams
Protein: 71 grams
Fat: 86 - 151 grams
Water: 3.7 Liters (about 16 cups)
While I'm not mad at the 630 grams of carbs suggested, I think it may be a bit of overkill, and I know from personal experience that 70 grams of protein is going to make me feel like a flaccid, limp bag of protoplasm. I think they almost nailed the water intake. Good job USADA. Whups...USDA. Same thing? One tests for dope, one gives dopey nutrition advice.
"Elevated protein consumption, as high as 1.8-2.0 g · kg(-1) · day(-1) depending on the caloric deficit, may be advantageous in preventing lean mass losses during periods of energy restriction to promote fat loss."
That sounds closer to the truth for me. Around 150-175g of PRO a day and I recover well, move well and feel alive! If I slip and forget to keep intake up on a training day, I feel it. As I get older, more and more...
Which brings me to:
As we age, the habitual intake of high quality protein in servings of 25-30g at breakfast, lunch and dinner may delay sarcopenia, or the loss of muscle due to aging.
So, there it is.
Simply stated: get enough to feel good. If you train hard 1.8 - 2g per kg of body weight is a safe bet. If you don't train hard, get a little less. As you age, keep getting it and maybe even more. If you train hard, get more to rebuild and recover.
Good sources of protein
Food - Protein (grams)
3 ounces tuna, salmon, haddock, or trout - 21
3 ounces cooked turkey or chicken - 19
6 ounces plain Greek yogurt - 17
½ cup cottage cheese - 14
½ cup cooked beans - 8
1 cup of milk - 8
1 cup cooked pasta - 8
¼ cup or 1 ounce of nuts (all types) - 7
1 egg - 6
Source: USDA National Nutrient Database, 2015