The Macro diet has recently become popular in gyms and fitness institutions. It is similar to the concept of calorie counting, but instead counts macronutrients. One version is referred to as ‘If It Fits Your Macros’ (IIFYM).
What are macronutrients?
Macronutrients are the component in food which provide energy, which is measured in kilojoules or calories. The three main macronutrients are carbohydrate, protein and fat. These nutrients are all essential, and have different physiological functions.
The energy values provided by macronutrients are:
- Carbohydrate: 16kJ per gram
- Protein: 17kJ per gram
- Fat: 37kJ per gram
There are two types of carbohydrate; complex carbohydrate or simple carbohydrates. Complex carbs are generally better for daily consumption and found in foods such as cereals, pastas, grains and bread with the wholemeal and wholegrain varieties preferred as they are higher in fibre. Food referred to as ‘simple carbs’ tend to be less healthy as they are often processed with added salt and saturated fats as well as sugar. If is best to only choose these foods occasionally. Highly processed ‘simple carbs’ are called discretionary foods (aka junk) and include soft drinks, chocolate, lollies and snack foods.
Protein is a macronutrient needed for growth and to repair and maintain body cells, organs and muscles. Protein is found in large quantities in meat, chicken, seafood, tofu, eggs, legumes, and nuts and some seeds.
Fats are commonly classified as saturated (unhealthy) or unsaturated (healthy). Saturated fats are found in foods such as processed meats like salami, pepperoni and bacon, fatty red meat and many fried foods. Unsaturated fats (also known as monounsaturated and polyunsaturated) tend to lower your blood LDL (bad) cholesterol when they replace foods high in saturated fats. Food that contain a lot of unsaturated fat include vegetable oils, oily fish and nuts and seeds.
It is important to remember that foods don’t contain only one type of macronutrient. For example, a piece of salmon contains both saturated and unsaturated fat and protein, legumes contain protein and complex carbohydrates, and a croissant contains simple carbohydrate and saturated fat.
How does the Macro diet work?
The diet focuses on creating a specific macronutrient goal relevant to your personal goals, such as weight loss or muscle gain. You then track the different macronutrients from the your foods you eat, as well as your total energy intake and then modify the foods you eat according to your macronutrient distribution goals. Often, a mobile app, such as Easy Diet Diary is used for tracking purposes.
For example, your energy requirements might be 8000kJ per day, and your macronutrient intake distribution might be 45% carbohydrate, 40% protein and 15% fats. This equals:
Carbohydrates: 0.45 x 8000 = 3600kJ
Protein: 0.4 x 8000 = 3200kJ
Fat: 0.15 x 8000 = 1200kJ
From here, you track your food intake according to these proportions of macronutrients. If it sounds complex, that because it is.
What does the science say?
In Australia, we have detailed dietary guidelines which outline recommended daily serves of foods, and suggested daily macronutrient proportions. This is called the Acceptable Macronutrient Distribution Range. These recommended ranges are broad with the appropriate macronutrient proportionsbeing:
- Carbohydrate: 45-65%
- Protein: 15-25%
- Fat: 20-35%
- Saturated and trans fat: <10%
There is little research specifically testing the Macro diet. However, there is a lot of research that has tested whether specific macronutrient ratios are better for weight management. A review of 14 popular diets with varying macronutrient ratios found no specific diet was better than others in achieving weight loss over six months. Across all diets weight loss diminished by 12 months.
Pros
- Tracking macronutrients has been shown to be associated with improved performance for individuals competing in endurance sports or bodybuilding as it can help them to by achieving specific goals such as making weights, increasing muscle mass, or carbohydrate loading for endurance events.
- Can be an educational tool to help raise awareness of energy density and nutrient composition of different foods eaten.
Cons
- It can be difficult to keep up for every meal and especially for meals that you don’t prepare for yourself.
- Given most foods contain more than a single macronutrient. This can make tracking specific macronutrients difficult.
- Tracking macronutrients alone can result in high consumption of discretionary foods. Overall diet quality is important and higher when most foods eaten are nutrient-rich, also called ‘core’ foods. These are the vegetables, fruits, lean sources of protein, wholegrains and foods rich in calcium as shown in the AGHE for more information.
- There is a lack of high quality research to determine the effectiveness of this diet.
The bottom line
Overall, macronutrient tracking may be helpful for some individuals and population groups with specific body composition or training goals, such as elite athletes. It can also be helpful in developing an awareness ofthe nutrient composition of common foods. However, it can be a tedious and time consuming method that is not always applicable to every meal, making it a challenging approach longterm. It is also difficult to know what your individual requirements are,. A practical and sustainable to be more aware of what you’re eating, but with an easier approach, is following the plate method. This mean filling ½ your plate with non-starchy vegetables, ¼ with lean protein foods and ¼ with wholegrains.
