According to a 2005 article in Current Sports Medicine Reports, the Institute of Medicine's current recommendations state that persons 19 years of age and older should get 10% to 35% of their daily calories from protein.
For a 2,000 calorie diet, that translates to between 200 to 700 calories from protein. You may also multiply 0.8 g of protein per kilogram of body weight to get how much protein you require each day.
With a little calculation, this is 54 g of protein for a female weighing 150 pounds or 65 g for a guy weighing 180 pounds.
Since most people get their protein from meat, here's a helpful tip for figuring out how many grams of protein are in most meats: A serving of meat that is 3- to 4-ounces in size (about the size of a deck of cards) has around 30 g of protein, compared to 1 ounce's 7 g of protein.
The IOM's guidelines, however, come with a catch: Eating less protein than recommended can leave you deficient in this essential nutrient, which could result in health problems including increasing muscle loss.
According to a 2019 review in Nutrients, recent research indicates that aiming for more, for instance, between 1.3 g and 1.8 g per kilogram of body weight (roughly 88 g to 122 g for women, 105 g to 145 g for men), may be optimal for health, especially when it comes to preventing age-related muscle loss.