In your 30s, your muscle mass begins to naturally decline; after 50, this decline only accelerates. However, adequate consumption of protein, paired with resistance training, dramatically decelerates age-related loss in muscle mass and increases strength in individuals of all ages. As it ages, the human body needs even more protein to meet the same physiological demands. The Acceptable Macronutrient Distribution Range (AMDR) for adults ranges from 10-35 percent of total caloric consumption daily. The World Health Organization, United Nations University, and American Dietary Guidelines recommend approximately 0.8 grams of protein per kilogram of body weight per day for adults. This translates to about 0.36 grams per pound. The Recommended Dietary Allowance (RDA) for adults over the age of 18 is only 46 grams per day for females and 56 grams per day for males. According to these guidelines, a 180-pound adult would only require about 65.6 grams of protein per day. This works out to only about 13 percent of calories based on a 2,000-calorie diet. This falls at the low end of the AMDR range mentioned above. RDA recommendations are based on the minimum protein requirements to avoid malnutrition. For example, if you calculate protein needs using the 10-35 percent range as dictated by the AMDR, then daily protein needs range from 50-175 grams of protein per day based off a standard 2,000-calorie diet. So, although the acceptable range for adults over the age of 18 is 50-175 grams of protein per day, the current RDA for protein only barely meets this range for the average adult.