nutrition | July 22, 2017 | Author: Naturopath
Are you confused about macronutrients and how much of each you should be eating? Don't know your fish from your fruit? Your chips from your chicken? You are not alone. The way we view macronutrients - carbohydrates, protein and fats - has changed over the last few decades with advancements in nutritional knowledge and research.
First, let’s go over the basics:
Carbohydrates, proteins and fats are energy-yielding nutrients, measured in kilojoules (American food labels use Calories, instead). Compared with micronutrients (such as vitamins, minerals and phytochemicals), which are essential for health but are needed in small quantities, macronutrients are needed in large quantities for everyday function.
Carbohydrates - “carbs” - are the body’s main source of energy. When digested, carbs break down to glucose (sugar).
Sugar (also known as simple carbohydrates) – sugar can be naturally occurring as in fruit or milk, or added to many processed foods such as cakes and biscuits, ice cream, sugar-sweetened drinks, flavoured yoghurts, breakfast cereals, etc. There is a general consensus that too much sugar in the diet can contribute to health problems and obesity.
Starch (also known as complex carbohydrates) – starchy foods include peas, corn, dried beans, potatoes, oats, barley and rice.
Fibre – fibre is a non-digestible carbohydrate in plant food, meaning the body cannot break it down. Fibre helps stabilise blood sugar levels, reduce cholesterol, and improve the sensation of feeling full and satisfied after eating. Animal food sources contain no fibre. Good fibre sources include whole grains (such as brown rice, buckwheat, oats, barley and quinoa), green leafy vegetables and other vegetables (such as broccoli, carrots, beetroot, potatoes and sweet potatoes), fruit (apples, berries), legumes (beans, lentils, chickpeas), and flaxseeds.
Proteins are large molecules that are made up from smaller compounds, called amino acids. Protein is essential for building our muscles, bones, skin, cartilage, and blood. It provides us with energy, and needed for the structure and function of hormones, enzymes, antibodies, and tissues.Both animal foods and plant foods contain protein. However animal sources of protein - including meat, poultry, fish, eggs and dairy products - contain all of the amino acids that the body cannot make by itself, and as such are considered to be complete proteins.
Plant foods, such as fruits, vegetables, legumes, grains, nuts and seeds, are referred to as incomplete proteins. Although they also contain protein, some may lack one or more essential amino acids.
Many studies have shown that high consumption of red meat can increase the risk of chronic diseases. The World Health Organisation classified processed meat (such as hot dogs, ham, sausages, corned beef, biltong or beef jerky) as a Group 1 carcinogen, the same category as tobacco smoking and asbestos, and recommends limiting intake of red meat.
Fats, also called lipids, have important functions and are essential for good health. Fats are a major source of energy, they produce hormones, keep the body warm, support cell growth, and aid in absorption of the fat-soluble vitamins A, D, E and K.
Monounsaturated fat – this type of healthy fat is predominant in the Mediterranean diet, and is found in olives, olive oil, most nuts, avocado, and canola oil. Research shows that the traditional Mediterranean diet reduces the risk of heart disease, and is associated with a reduced incidence of cancer, Parkinson’s and Alzheimer’s diseases.
Polyunsaturated fat – Polyunsaturated fats are essential fats. That means that your body cannot make them, and as a result they must be obtained from the food we eat. Polyunsaturated fats can be subdivided into two main types:
Polyunsaturated fats are healthy fats. However, it is important to maintain a correct balance of omega 6:omega 3 ratio. The Western diet is characterised by excess consumption of omega 6 fatty acids, mainly due to the widespread use of vegetable oils. A high omega 6:omega 3 ratio is thought to be inflammatory. It is important therefore to increase intake of omega 3 foods, and reduce consumption of vegetable oils, to reduce the risk of various chronic inflammatory diseases.
Saturated fat – a high saturated fat intake - found in red meat, dairy products, and coconut milk - has been associated with a raised blood cholesterol level, which is one of the risk factors for coronary heart disease. Although not all health experts agree, government guidelines recommend limiting intake of foods containing saturated fat. However, it is important to replace them with quality foods that contain predominately polyunsaturated and monounsaturated fats, rather than with carbohydrates.
Trans fat – these fats are considered to be the unhealthiest. They are found in highly processed food, such as margarine, vegetable shortening, chips, fast food, and fried food.
Current nutritional research is yet to find the optimal macronutrient balance. All macronutrients are important, and individual needs vary. Nevertheless, the type/quality of carbs, protein, and fat is equally if not more important than their ratio.
American Diabetes Association 2017, Making Healthy Food Choices, ADA. : Available at: http://www.diabetes.org/ [Accessed July 11, 2017].
British Nutrition Foundation, Nutrients, Food and Ingredients, BNF. Available at: https://www.nutrition.org.uk [Accessed July 12, 2017].
Harvard Medical School 2015, The truth about fats: the good, the bad, and the in-between, Harvard Health. Available at: http://www.health.harvard.edu. [Accessed July 12, 2017].
National Health and Medical Research Council 2014, Macronutrient Balance | Nutrient Reference Values. NHMRC, Available at: https://www.nrv.gov.au [Accessed July 12, 2017].
World Health Organization 2015, IARC Monographs evaluate consumption of red meat, WHO, Available at: http://www.iarc.fr/en/media-centre/pr/2015/pdfs/pr240_E.pdf [Accessed July 12, 2017].