Regardless of whether you are a bonafide meat eater or vegan, we all need to include protein in our diet. This is because protein plays an essential role in the proper functioning of the body as they are the building blocks for life. Protein makes up about 16 percent of the human body and is part of every single cell in the human body (i.e., brain cells, muscle, skin, hair and nails). So, as you can see, protein is an essential part of a healthy and nutritious diet. Foods that contain protein include fleshy foods (poultry, beef, lamb and fish), eggs, dairy, nuts, seeds, legumes (beans and lentils), and some grains.
When digested, protein is broken down into amino acids, which are chemically linked to each other by peptide bonds. There are about 20 different amino acids that can be put together in different combinations to make up the millions of proteins found in nature. The two broad classes of amino acids are those that can be made by the body (non-essential amino acids) and those that must be supplied through your diet (essential amino acids). The table below outlines some of the food sources providing both types of amino acids.
The amount of protein you need depends on your weight, age and lifestyle. As a rough guide, the recommended dietary intake (RDI) for protein (measured in grams per kilogram/ounces per pound of bodyweight) is:
- 0.75 g per kg (0.012 oz per lb) for adult women
- 0.84 g per kg (0.0135 oz per lb) for adult men
- 1 g per kg (0.016 oz per lb) for pregnant and breastfeeding women, and for men and women over 70.
For example, a 75 kg adult male would need 63 g of protein per day. It is recommended that up to 25 per cent of total energy intake per day is from protein sources. Your body can’t store protein and will excrete any excess. Therefore, the most effective way of using the daily protein requirement is to eat small amounts at every meal. Using the example of the 75 kg male above, this would require that he eats approximately 21 g of protein at three meals each day. Most people eat more protein than they need, so deficiencies are rare.
Essential Amino Acids (Complete Proteins)
- Animal sources such as chicken, beef, lamb, seafood, pork, veal, and turkey
Plants containing essential amino acids include:
- Amaranth seed
Since our body cannot make these amino acids (there are nine) it is essential they are supplied through your diet.
Non-essential Amino Acids (Incomplete Proteins)
If you are following a strict vegetarian or vegan diet, combine foods from two or more incomplete proteins to create complete proteins.
The body uses amino acids in three main ways:
- Protein synthesis—new proteins are created constantly. For example, as old, dead cells are sloughed off the skin surface, new ones are pushed up to replace them.
- Precursors of other compounds—a range of substances are created using amino acids, (for example, enzymes, hormones, the brain chemical (neurotransmitter) serotonin and the ‘fight or flight’ chemical adrenalin).
- Energy—although carbohydrates are the body’s preferred fuel source, about 10 per cent of energy is obtained from protein
At around 50 years of age you will begin to gradually lose skeletal muscle. This loss is known as sarcopenia, and is common in the elderly. It is also worsened by chronic illness, poor diet or inactivity. Increasing the amount of protein you eat to the upper end of the RDI range, as well as weight bearing exercise, can help maintain muscle mass and strength. This is vital for your ability to stay mobile and reduces your risk of injury.
Strenuous Exercise and Extra Protein
Contrary to popular belief, people who exercise vigorously or are trying to put on muscle mass don’t need to consume extra protein. Studies show that weight-trainers who do not eat extra protein (either in food or protein powders) still gain muscle at the same rate as weight-trainers who do supplement their diets with protein. A very high protein diet can strain the kidneys and liver, and prompt excessive loss of the mineral calcium. The best thing you can do to help improve or maintain muscle mass is to consume protein from your RDI within 30 minutes of exercising. Make this protein source high-quality, lean and combined
with a low GI carbohydrate to help maintain your body’s protein balance. Studies have shown this to be beneficial, even if exercise is low to moderate intensity aerobic exercise (such as walking). If you can’t get the required protein/carb combo into your body through food within 30 minutes, I can recommend the wonderful Clean Lean Protein powder. It is organic, delicious and made from pea protein, so totally fine for vegans and vegetarians. And it’s not full of all the manufactured additives of many commercial protein powders. To learn more about Clean Lean Protein, click here.
Nutrition 101 – Bonus Tip
A general Guide to Healthy Eating recommends particular servings per day from the lean meat, poultry, fish, eggs, legumes and beans, and nuts and seeds food category, including:
- 3 servings for adult men
- 2½ servings for adult women
- 2½ to 3½ servings for breastfeeding and pregnant women, and people over 70
Examples of a standard serving size is listed below:
- 65 g cooked lean red meats
- 80 g cooked poultry
- 100 g cooked fish fillet
- 2 large eggs
- 1 cup cooked dried beans, lentils, chickpeas, split peas or canned beans
- 170 g tofu
- 30 g nuts or seeds
- 250 mL (1 cup) milk
- 200 g (¾ cup) yoghurt
- 40 g (2 slices) hard cheese
By the way … do you have a protein intolerance (such as gluten)? Let’s explore these next week.
Until then … HAVE FUN!
Kris Abbey, the spa-going, health-nut, mother-of-three, is the publishing editor of Spa Life and Better Health magazines. She has passionately been involved in fitness, health, and wellness for over 30 years (and looks forward to at least another 30 years!).