BY Tara Baker
Sometimes as a nutritionist, I forget the simplest of things. The basics. We know them, but do we know why the basics are important? Why do we need some foods over others? We presume we know, but do we realise how important they are to our body function? I’m talking about macronutrients. These are the nutrients that provide us calories or energy. Nutrients are the building blocks for growth, metabolism and for other body functions. The word MACRO means large, which means they are required in large amounts. These are carbohydrates, proteins and fats.
The amount of calories that each one provides is different. Carbohydrate provides four calories per gram. Protein supplies four calories per gram and fat provides nine calories per gram.
Besides these three, the only other substance that provides us with calories is alcohol, which provides seven calories per gram. Alcohol however, is not a macronutrient because we do not need it for survival.
So why do we need Carbohydrates?
Carbohydrates are the main source of fuel and easily used for energy. All the tissues and cells in our body can use glucose for energy. Carbohydrates are needed for the central nervous system, the kidneys, the brain, muscles and our heart to function properly. Carbohydrates can be stored in our muscles and liver and used later for energy. They are super important in maintaining good intestinal health and waste elimination. Found in foods like grains (including rice), potatoes, fruits, milk and yoghurt. Also in vegetables, beans, nuts and seeds.
Fibre refers to the certain types of carbohydrates that we can't digest. These carbohydrates pass through the intestinal tract and help to move waste out of the body. Diets that are low in fibre have been shown to cause problems such as constipation and haemorrhoids and increase the risk for certain types of cancers, such as colon cancer. Diets high in fibre however, have been shown to decrease the risk of heart disease and obesity and also help lower cholesterol. Foods high in fibre, which I call ‘sweepers’ include fruits, vegetables and wholegrains. I advise pear, kiwi fruit and carrot to almost everyone I see.
Why do we need protein?
Most people fall short of their protein requirement but it can be easily met by consuming a balanced diet. We need protein for;
: Growth (especially important for children, teens and pregnant women)
: Tissue repair
: Immune function
: Making essential hormones and enzymes
: Energy when carbohydrate isn't available
: Preserving lean muscle mass
: Strong hair and skin repair
Protein is found in meats, poultry, fish, meat substitutes, cheese, milk, nuts and legumes. When we eat these foods, our bodies break down the protein they contain into amino acids. Some amino acids are essential which means we need to get them from our diet and others are nonessential, meaning our body can make them…So clever.
Protein that comes from animal sources contain all the essential amino acids we need. Plant sources do not.
Why do we need fat?
Poor old fat has received a lot of backlash over its potential to gain weight, however some fat is essential for survival. We can't run our car without oil, just as we can’t function without fats.
Fat is found in meat, poultry, nuts, milk products, butter, oils, fish, seeds, coconut and avocado. Dietary guidelines say we need 20-30% of our calories from good fats. These help aid with;
: Normal growth and development
: Energy (fat is the most concentrated source of energy)
: Absorbing fat soluble vitamins like A,D,E,K and carotenoids
: Maintaining cell membranes
: Balancing and producing hormones and cholesterol
: Many digestive functions
: Reducing pain in joints
By replacing saturated and trans fat in your diet with unsaturated fat found in avocado, olive oil, nuts and seeds, you are reducing your chances of heart disease, dementia and many other illnesses.
Brodie Gardner has a Masters in Exercise Physiology, Honours in Sports Science and competes as a professional triathlete. He has a long history working with elite athletes and has provided consultation services to numerous Australian sporting associations.