A person's daily protein needs vary by age, sex, physical activity level, and health status. However, it is generally recommended that 10% to 35% of total daily caloric intake come from this essential nutrient, which is fundamental for building and repairing the body's cells and tissues, as well as for growth and development throughout life. The U.S. Department of Agriculture, in its dietary guidelines released this year, stated that adults should consume between 1.2 and 1.6 grams of protein per kilogram of body weight. This is nearly double the previous recommendation of 0.8 g/kg, a shift that reflects the current focus on nutritional efficiency rather than the previous policy of setting a minimum intake to prevent nutrient deficiencies. Older adults and physically active individuals require more protein to build and maintain muscle mass. Meanwhile, high-protein diets can aid in weight loss or maintenance. Pregnant women also need increased amounts of protein. Conversely, individuals with certain medical conditions, such as chronic kidney disease, may need to reduce their protein intake. Signs of protein deficiency can include issues with hair, skin, and nails, increased appetite, a higher risk of infections, mood swings, and muscle weakness.
