Most healthy adults, including vegetarians, are advised to aim for 0.8 grams of protein per kilogram of body weight per day as a baseline. This recommendation originates from the Dietary Reference Intakes produced by the Committee on Dietary Reference Intakes at the Institute of Medicine and is widely used as the population-level reference for minimum needs. A 70-kilogram adult therefore requires about 56 grams of protein daily at that rate.
Daily targets and when to increase intake
Research led by Stuart M. Phillips at McMaster University emphasizes that certain groups benefit from higher intakes. Older adults, people recovering from illness, and those engaged in regular resistance training or endurance sport often do better with 1.2 to 1.6 grams per kilogram to preserve muscle mass and support recovery. The Academy of Nutrition and Dietetics also notes that well-planned vegetarian diets can meet protein needs across the lifespan if attention is paid to quantity and variety of sources. This does not mean every vegetarian must consume the higher amounts; needs depend on age, activity, health status, and goals.
Protein quality, combinations, and practical implications
Plant proteins differ from animal proteins in amino acid profiles and digestibility. Protein quality—often measured by methods such as PDCAAS or DIAAS—affects how much usable amino acid reaches the body. Soy and dairy-based proteins are high-quality sources; many legumes, grains, nuts, and seeds provide complementary patterns. For vegetarians, combining foods across the day—such as beans with rice or lentils with whole grains—improves the overall essential amino acid balance. Attention to leucine-rich sources is important for stimulating muscle protein synthesis, especially in older adults.
Culturally and territorially, vegetarian patterns vary. In South Asia, traditional meals of pulses with cereals supply a reasonable mix of amino acids at low cost but may require larger portions for equivalent protein. In Western vegetarian diets that include dairy and eggs, meeting targets is often easier. Environmental considerations also matter: shifting toward more plant-based proteins generally reduces greenhouse gas emissions per kilogram of protein, but meeting higher protein targets purely from plants can increase land or processing needs depending on the food choices.
Consequences of insufficient intake include slowed recovery after illness, gradual loss of muscle strength, and impaired immune responses. Monitoring is especially important for older vegetarians, pregnant and breastfeeding people, and athletes. Practical strategies include including a source of protein at each meal, choosing some higher-quality plant proteins such as soy or minimally processed legumes, and considering a nutrition assessment with a registered dietitian when needs are elevated.
Evidence sources include the Committee on Dietary Reference Intakes, Institute of Medicine and research by Stuart M. Phillips, McMaster University, along with position guidance from the Academy of Nutrition and Dietetics, all of which support tailoring protein targets to individual circumstances.