Protein is one of the three major food groups, along with carbohydrates and fats, and you need all three to function. But when you exercise, protein takes on special significance because of its complex role.
Protein is made up of amino acids, the building blocks of muscles, tissue, skin and organs. When you consume protein, your body breaks it down into those building blocks during digestion, to create new proteins to repair damaged tissue. During exercise, you are tearing and breaking down muscles to rebuild them stronger.
If you don’t consume enough protein, your body will be forced to break down existing muscle to obtain the amino acids it needs for repairs, says Cape Town sports dietitian Hanlie Jordaan. At a cellular level, it also needs protein for many complex functions, including transporting nutrients, synthesising hormones, keeping organs functioning, carrying out the instructions of DNA and keeping your immune system strong.
Types of protein
Your body requires 20 different amino acids to maintain health and it’s able to synthesise 11. The remaining nine, known as ‘essential amino acids’, must be obtained from the food you eat. The main sources are animal-based foods: meat, dairy products, eggs and fish.
“You can also get protein from plant-based foods such as beans, pulses and seeds, but no plant protein contains all nine essential amino acids,” says Jordaan. “You need to complement your plant proteins to get all nine – for example, you complement legumes (such as lentils) with grains (such as brown rice) to get all nine. The amount of food you’ll have to consume to get enough protein from plant sources will be more than if you eat meat sources.
“Iron is also in a less bioavailable form in plant sources than in animal sources – your body can’t absorb it fully. There are also numerous other vitamins and minerals you can’t find, or will struggle to find in plant sources, so it would be a good idea to consult a dietitian before going plant-based, to prevent deficiencies and injuries.”
How much protein do you need?
If you lead a sedentary life with little exercise, you need about 0.8g of protein per 1kg of body weight each day – that’s about 55g for the average man, 45g for the average women. But if you exercise regularly and vigorously, the recommended intake can be from 1.4kg to 2g per kg, according to the Academy of Nutrition and Dietetics and American College of Sports Medicine, depending on the type of exercise and intensity, spaced throughout the day after workouts.
In general, the average women should have a protein portion of meat the size of the palm of her hand with each meal, and the average man, a portion the size of two palms (for plant sources of protein, you will need more). As another simple guide, the Heart and Stroke Foundation of South Africa suggests the ‘Plate Model’, where half your plate consists of non-starchy veggies such as broccoli, cabbage and tomatoes; a quarter consists of high-fibre starches such as brown rice, whole grains, sweet potato and butternut; and the remaining quarter consists of lean protein such as grilled skinless chicken, fish, lean mince, ostrich meat or soya.
When should you have protein?
If you have a vigorous exercise regime, eat a portion of protein (about 15 to 40g, depending on your size and level of exercise) within 30 minutes of exercising, when your muscles are most receptive, says Jordaan.
For convenience, this can take the form of a commercial protein drink, usually based on whey, soya or pea powder. But a protein and carb snack, such as peanut butter spread on a banana or wholewheat cracker, or two eggs on two slices of toast, can do the trick as part of a balanced diet, Jordaan says. You should be able to obtain all the protein you need from natural sources. “Sometimes you need to add carbs to your post-workout meal to optimise recovery,” she says. “You can ask your dietitian if this is needed and in what quantities.”
Also read: Why is whey protein so popular?
IMAGE CREDIT: 123rf.com
* Reliance on any information provided on this Website is solely at your own risk.
The content of this Website is provided as a service to you for educational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. If you are experiencing symptoms or need medical advice, you should seek the advice of your healthcare professional.