8 Protein Facts: What Protein Does, How Much You Need and the Best Sources

Protein is made from amino acids

Amino acids are the building blocks of protein. The body can make some non-essential amino acids on its own, while nine are considered essential because they must come from food: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. ^{[1, 3]}

You do not need to memorise the list. Eating enough protein from a varied diet is the practical way to obtain the amino acids your body needs.

“Complete” and “incomplete” protein is a useful shortcut — but not the whole story

Complete proteins are food sources that provide all nine essential amino acids in adequate proportions. They include animal-based foods such as eggs, milk, fish and meat, as well as plant-based sources such as soy and quinoa.

Some plant proteins are lower in one or more essential amino acids, which is why eating a varied diet that includes legumes, tofu and tempeh, nuts and seeds, whole grains and peas throughout the day can help meet protein needs. ^{[1, 3]}

Complementary proteins do not need to be combined at every meal, as long as the overall diet is varied and adequate.

Protein does much more than build muscle

Protein supports growth, maintenance and repair throughout the body. It is found in muscle, bone, skin and blood, and is used to make enzymes, hormones, transport proteins and antibodies involved in immune defence. ^{[1, 3]}

Too little protein can affect strength, healing and nutritional status

Severe protein-energy malnutrition can cause muscle wasting and conditions such as marasmus or kwashiorkor, especially where overall food intake is inadequate. ^[1] In everyday practice, people who are older, unwell, recovering from illness, eating very little, or following highly restrictive diets may need extra attention to protein intake.

Being vegetarian does not automatically mean a person is protein deficient. Vegetarian and vegan diets can provide enough protein when they include a good variety of legumes, soy foods, nuts, seeds and grains. ^[3]

How much protein do you need each day?

There is no single number that fits everyone. International adult reference values are around 0.8–0.83 g of protein per kilogram of body weight per day for generally healthy adults, while Malaysia’s Recommended Nutrient Intakes (RNI) provide age- and sex-specific daily targets. ^{[2, 3]}

Your needs may be higher during growth, pregnancy, breastfeeding, regular athletic training, recovery from illness or in certain medical conditions. If you have kidney disease or another condition that affects nutrition, your protein target should be individualised with a healthcare professional or dietitian. ^[6]

Athletes often need more protein — but timing is not everything

For many healthy exercising adults, sports-nutrition guidance suggests around 1.4–2.0 g/kg/day can support training adaptation and muscle maintenance or gain. ^[4] The total amount of protein consumed throughout the day is more important than focusing on the precise timing of protein intake.

Protein before or after resistance exercise can both support muscle protein synthesis. Practical food options include milk or yoghurt, eggs, fish, chicken, tofu, tempeh, soy milk, beans or a suitable protein shake when food is inconvenient. ^[4]

Pregnancy increases protein needs, especially later in pregnancy

Malaysia’s RNI recommends extra protein during pregnancy because maternal and fetal tissues are growing. The additional intake is approximately +0.5 g/day in the first trimester, +8 g/day in the second trimester and +25 g/day in the third trimester. ^[2]

These extra needs should generally come from normal food rather than high-protein supplements. If protein needs cannot be met through diet alone, consult a healthcare professional before considering high-protein supplements routinely during pregnancy. ^{[2, 5]}

Protein powder can be a convenient supplement

Whey, casein and pea protein are common powder options. They can make it easier to reach a protein target when appetite, schedule, training or dietary preferences make food less convenient. Protein powders can be an easy way to increase protein intake when needed.

However, they may lack fibre, vitamins, minerals and other nutrients found in whole foods, so they should complement rather than replace a varied diet. ^{[1, 7]}

If you choose a protein powder, check the serving size, protein amount, added sugar and other ingredients. People who are pregnant, have kidney disease, take medicines or have food allergies should check with a healthcare professional before using supplements regularly. ^{[5, 6, 7]}