Nutrition Basics: Proteins

Proteins are the most important nutrient in food, serving a structural, protective, and energetic role in the body. During exercise or intense physical labor, a higher intake of protein is essential. This means that if we want to reshape our body in terms of appearance, health, strength, and fitness, we need a complete dietary shift in favor of proteins. The minimum daily intake during training ranges from 1.6g to 3g of protein per kilogram of body weight. Protein-rich foods include meat, fish, eggs, milk, cheese, beans, and peas. An additional source of protein is powdered protein concentrates, where protein content can reach up to 90%. If dietary intake is insufficient, protein supplements are necessary.

Function of Proteins

Proteins, also known as “proteins” from the Greek word meaning “first” or “most important,” play a triple role in the body:

• Structural role: Protein molecules build tissue, organs, and muscles, assist in tissue regeneration, and contribute to the breathing process through hemoglobin in the blood.

• Protective role: Proteins are key in defending the body and strengthening the immune system.

• Energy role: In the absence of other nutrients, proteins serve as fuel, providing 4 kcal per gram. However, proteins are a costly energy source and are used when carbohydrates and fats are lacking.

Structure of Proteins

Proteins are made of amino acid molecules. Dietary proteins are broken down into amino acids during digestion and then absorbed into the bloodstream and delivered to cells. Amino acids are divided into two groups:

• Essential amino acids: These cannot be synthesized in the body and must be consumed through food.

• Non-essential amino acids: These can be produced in the body from other sources like carbohydrates or essential amino acids.

Essential Amino Acids

The essential amino acids are: threonine, valine, leucine, isoleucine, lysine, tryptophan, methionine, phenylalanine, and histidine. Each has a specific role in the body, and in sports nutrition, the branched-chain amino acids (BCAAs)—valine, leucine, and isoleucine—are especially important for muscle anabolic processes.

All nine essential amino acids are only found together in animal-based foods, which is why vegetarians and vegans must combine different plant-based foods to meet their needs.

Daily Requirements

Protein needs are widely debated. For sedentary adults, the recommended intake is 0.5g–0.8g/kg of body weight. With increased physical activity, the requirement rises. Children and adolescents also require higher amounts—up to 1.5g/kg. For adults and active individuals, 1.6g–3g/kg is recommended. Regardless of activity level, everyone aiming to maintain health and prevent disease should increase protein intake. Ideally, protein should make up 30–40% of daily caloric intake.

Summary and Advice:

• Aim to consume 2g of protein per kilogram of body weight

• Proteins should make up 40% of your total daily energy intake

Protein in Food

Foods rich in protein include eggs, milk, dairy products, meat, and fish. Among plant-based foods, protein-rich options include beans, peas, fava beans, soy, and nuts. The nutritional value of food is often determined by the amount of protein per 100g, meaning higher-protein foods are usually more expensive.