How Much Protein Is Actually Right for You?

Ultra-processed foods—those containing high levels of fat, sugar, salt, and various additives—stimulate the brain’s reward system, releasing dopamine and creating a sense of pleasure that makes people strongly dependent on such foods. This has fuelled a surge in modern “diseases of affluence” such as obesity, diabetes, and cardiovascular and cerebrovascular conditions. One countermeasure is to stay away from ultra‑processed foods, but many people find that difficult. Hence, some food experts suggest eating more protein‑rich foods to counterbalance the intake of high sugar, fat, and salt. At the same time, high‑protein diets have become fashionable among athletes and fitness enthusiasts, as they are believed to promote strength, health, and even longevity.

How much protein each person needs each day, however, remains uncertain. Most people follow the guidelines issued by health and nutrition authorities. In 2005, the World Health Organization (WHO) recommended that healthy adults consume 0.8–1 gram of protein per kilogram of body weight per day. The Chinese Nutrition Society, in its _Dietary Reference Intakes for Chinese Residents (2023 Edition)_, suggests 65 grams per day for men aged 18–64 and 55 grams for women in the same age group; for those over 65, the figures are 72 grams for men and 62 grams for women.

In contrast, most authoritative health organisations in Europe and the United States recommend at least 1 gram per kilogram of body weight per day for adults. By this standard, a person weighing 70 kilograms would need about 250 grams of cooked chicken (which contains roughly 68 grams of protein) daily. However, some now argue that even this amount is insufficient and that the intake should be more than doubled—meaning at least 500 grams (about one pound) of cooked chicken or an equivalent portion of other high‑quality protein sources like beef, lamb, pork, duck, or fish.

Yet Donald Layman, a researcher at the University of Illinois Urbana‑Champaign who specialises in protein requirements, points out that evidence suggests an optimal range of 1.2–1.6 grams per kilogram per day. This range is more practical and better suited to specific populations, especially older adults (who naturally lose muscle with age) and certain athletes or people aiming to build muscle and improve fitness, because higher protein intake can slow muscle loss.

A three‑year follow‑up study of 2,066 adults aged 70–79 found that those with the highest protein intake (about 1.1 g/kg/day) lost 40% less muscle mass than those with the lowest intake (about 0.7 g/kg/day). Nevertheless, for older individuals, 1.1 g/kg/day may still be insufficient; 1.2 grams appears better, as appetite and overall food consumption tend to decline with age, so increasing the protein proportion is more beneficial. This can usually be achieved through regular meals and snacks, without needing extra supplements.

For fitness enthusiasts who propose 2.2 grams per kilogram per day, other researchers at the same university consider this excessive and inappropriate for most people. Following the principle that “enough is enough, and more is not better,” excessive protein intake is generally harmless but can be harmful to those with kidney disease. Above 1.6 g/kg/day, the surplus provides no extra benefit and may even put the body into an inefficient state, wasting dietary protein. Furthermore, increasing protein alone has limited effects on preserving muscle; it should be combined with exercise. A 2017 review confirmed that resistance training (e.g., weightlifting) together with protein supplementation promotes greater muscle gain and strength.

The choice of food sources is equally important, because different foods contain different types and amounts of protein. Proteins are made of 20 amino acids, of which 9 are “essential” (cannot be synthesised by the body) and must come from the diet: lysine, tryptophan, phenylalanine, methionine, threonine, isoleucine, leucine, valine, and histidine. Animal‑based foods contain these essential amino acids in proportions that closely match human needs, whereas plant‑based foods, though they also contain them, have profiles tailored to plants. Thus, animal sources are generally more efficient for meeting human protein requirements. However, this does not mean plant foods cannot suffice—they simply require greater variety and larger quantities to compensate for their lower quality.

The dosage for replacing animal protein with plant protein is debated. The U.S. Department of Agriculture (USDA) states that 14 grams of almonds can replace the protein in 28 grams of chicken breast, but Layman and his team suggest that more than 115 grams of almonds are needed for the same protein. Another study involving 56 young adults found that animal protein led to greater increases in body protein synthesis than an equal amount of plant protein. Still, plant foods can adequately meet needs if consumed in larger amounts, and some researchers argue that plant protein is preferable because saturated fats in red meat may raise cardiovascular risk, while meat production also contributes to greenhouse gas emissions and environmental damage.

In summary, the evidence suggests that for normal adults, daily protein intake should be about 1.1–1.2 grams per kilogram of body weight; for special groups such as the elderly, athletes, and fitness enthusiasts, it may be raised to 1.2–1.6 g/kg/day. Intakes above 2 g/kg/day are wasteful and potentially harmful for kidney patients. Protein should come from a variety of foods, with an emphasis on high‑quality sources including eggs, milk, soy, white meat (fish, poultry), and red meat (pork, beef, lamb). High‑quality protein should account for one‑half to two‑thirds of the total daily protein requirement.

A practical daily plan could include staple foods (rice, steamed buns, etc.)—over 300 grams for men and over 250 grams for women, providing about 20 grams of protein; 150 grams of lean meat (from aquatic, poultry, or livestock sources), supplying about 30 grams; one or two eggs, giving 7–14 grams; one or two bags of milk (250–500 grams), contributing 8.3–16 grams; 100–150 grams of soy products, about 10 grams; and 500 grams of vegetables plus 250 grams of fruit, providing about 5 grams. For a normal person, consuming these amounts daily would ensure adequate protein intake.