Protein: The building blocks of the body

Health and Fitness
Of all the macronutrients, protein is the one that hasn’t received much negative press. It’s loved by all. And for good reason. Protein is the building blocks of almost all our major body tissues – including the heart – and should be consumed daily for overall good health, growth and repair.

What is protein?

Every cell, tissue and organ in the body is made up of protein – muscles, bones, skin, connective tissues, enzymes and so much more. In terms of food, protein is a macronutrient made up of smaller nutrients called amino acids. Some amino acids can be synthesised by the body, but there are nine amino acids that can’t. These are known as essential amino acids, and we need to eat them daily to meet our body’s needs.

The best quality sources of protein come from animal products: meat, eggs, dairy, etc. These sources are complete, meaning they contain the full set of essential amino acids. Plant-based proteins are often incomplete, but with careful planning, a plant-based diet can offer you all the amino acids you need if that's how you choose to eat.

Why do we need protein in our diets?

1. Protein helps build muscle

When you engage in regular weight bearing or resistance exercise combined with moderate protein intake, your body can build and strengthen muscle.

Muscle is a vital contributor to your metabolism because it’s the most metabolically active cell in the body, burning up to 15–20 times more calories than other cells, particularly when you’re moving or exercising. Therefore, the more muscle you have, the more energy you burn every day, and the easier it’ll be for you to maintain a healthy weight and still enjoy all the foods you love.

2. Protein helps you feel full

One of the principles of healthy eating is learning which foods help fill you up without overeating. Protein-rich foods help you feel fuller from a meal because they take longer to digest than other nutrients. This is a really important technique for combatting your mid-afternoon binge session or sugar craving, especially if you live an active lifestyle. A lot of people feel hungry and tired at this point in the day because they haven’t eaten enough protein at breakfast and lunch.

Aiming for an adequate serve of a quality protein-rich food at every meal, especially for breakfast and lunch, will keep you in much better control of your appetite. You’ll also feel less inclined to tuck into an unhealthy snack late in the afternoon. Long term, you’re better off eating more good-quality food like the carbohydrate sources we’ve talked about previously and the good sources of protein mentioned below, than skimping on these healthy foods only to overeat unhelpful (high sugar, high processed) foods later on.

3. Protein helps control your appetite

Appetite is the resulting outcome of a number of factors that are circumstantial, physical and psychological. Some of the physiological factors that will affect your appetite are your blood sugar levels and the types of foods that you eat. If you constantly consume high sugar and highly processed foods, you’ll quickly feel out of control of your appetite and more inclined to eat more of these types of unhealthy foods. Your body’s blood sugar levels will fluctuate, making it much harder to maintain a healthy weight.

Research shows that the addition of protein at mealtimes, especially breakfast, helps control your appetite, and you are less likely to overeat over the course of the day.

How to add protein to your meals

Foods are not all one macronutrient; they are a mixture of fat, carbohydrate and protein, just in differing amounts. In saying that, there are some foods that are better protein sources than others. The best choices are:

  • Meat: lamb, beef, pork, kangaroo, game meats, etc
  • Fish: basa, ling, salmon, snapper, baramundi, tuna, etc
  • Seafood: prawns, crab meat, squid, muscles, oysters, etc
  • Poultry: chicken, turkey, duck, etc
  • Eggs
  • Dairy: milk, yoghurt, cheese
  • Soy: milk, beans, tofu, tempeh
  • Legumes: beans, lentils, chick peas
  • Nuts: peanuts, cashews, almonds, walnuts, macadamias


It’s also important to note that just like carbohydrate-rich foods, your protein sources should be minimally processed. This means that highly processed foods, such as salami, bacon, sausages, rissoles, flavoured milks, confectionary style yoghurts, custards, nuggets, schnitzels, fish fingers, seafood extender, should be eaten sparingly and in moderation. Fresh and whole is always best. 

Header image: NordWood Themes / Unsplash

Kate Freeman
Kate Freeman is HRI's resident nutritionist. She is a registered nutritionist from Canberra, Australia and the creator and managing director of the largest private nutrition practice in Canberra, The Healthy Eating Hub. Kate consults, writes, presents and mentors in the field of nutrition and has over 10 years of experience in the industry.

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