Protein Intake Recommendations for Adults

General Adult Protein Requirements

The National Academy of Sciences recommends a standard Recommended Dietary Allowance (RDA) for protein in adults of 0.8 g/kg body weight per day, which represents the minimum amount required to avoid progressive loss of lean body mass 1
For a reference 70 kg adult, the daily protein intake equals approximately 56 g of protein daily for men and 46 g for women, based on a reference weight of 57.5 kg, as suggested by the National Institutes of Health 2

The International Society of Sports Nutrition recommends protein intake of 1.0-1.2 g/kg/day for most adults, providing additional health benefits beyond the minimum RDA 3
For individuals engaged in physical activity, the American College of Sports Medicine recommends higher protein intakes: minimal physical activity, 1.0 g/kg/day 3, and intense physical activity, 1.6 g/kg/day or higher 4

The European Society for Clinical Nutrition and Metabolism (ESPEN) guidelines recommend at least 1.0 g/kg/day for all older persons, with adjustments based on nutritional status, physical activity level, and disease status 4, 3
For older adults with acute or chronic illness, daily amounts of 1.2-1.5 g/kg have been suggested by the American Geriatrics Society 3

The Academy of Nutrition and Dietetics suggests that both animal and plant proteins can meet protein needs when consumed in adequate amounts 2
Vegetarians and vegans can meet protein requirements by consuming a variety of plant protein sources throughout the day, as recommended by the Vegetarian Resource Group 2

The National Academy of Sciences notes that protein requirements may be underestimated by 10-20% when using self-reported measures compared to more objective methods 1
The American Heart Association recommends considering protein intake in context of total energy intake and overall diet quality 5, 1
For critically ill patients, the Society of Critical Care Medicine suggests that higher protein intake (around 1.2 g/kg/day) compared to lower intake (<1.2 g/kg/day) shows little to no difference in mortality but may slightly increase length of ICU and hospital stay 6, 7