So, you know that in order to lose or gain weight, it’s about changing the energy balance; eat more to gain weight, eat less to lose weight. Seems simple enough right? In order to do things right and get the best results, we need to know how to actually use calories and macronutrients to manage this equation? Which one is more important? Well, as much as it would be nice to have a cut and dry answer for this, we need to account for both to get the best results.
To start, calories and kilojoules are the measures of how much energy is in a food. Calories and kilojoules can both be used, however, in Australia, we use the metric measure kilojoules. It is common however to see calories used as the measure as it is a smaller number (1 calorie is equal to 4.2 kilojoules, kind of like converting inches into centimetres).
Everyone has a number of calories (energy) they need to consume each day to meet the energy cost of keeping their body alive, doing daily activities like walking and standing up, digesting food and exercise. How many calories you need will depend on your body size and composition, what you eat and how active you are. So, by counting calories, you can see if how many you consume matches the estimation of how much you need. When we overeat on calories- no matter if they are from healthy foods or the less healthful ones- we will put on weight over an extended period. If we eat less energy that is required to fuel our daily activities, we will see a reduction in body weight.
If you are wondering why some people only count macronutrients (macros for short) and not calories to stay on track, then we need to cover off on the relationship between calories and macros.
Macros are the three main compounds that we need to eat in order to get energy (calories); Carbohydrates, fats and protein. Each one of these macros contains a specific number of calories per gram that you eat:
- Carbohydrates yield 4 calories per gram eaten
- Fats yield 9 calories per gram eaten
- Protein yields 4 calories per gram eaten.
Because we know how many calories, we will get per gram eaten, we can ‘count macro’s’ which simultaneously gives us information about how much energy we are eating. For example, if you ate 400g of carbohydrates, you could calculate that you were taking in 1600 calories of energy (400g x 4 calories per gram equals 1600 calories). Using macros essentially gives up another layer of information about the make-up of the diet you are eating.
While calories are the most important number to pay attention to when managing weight, how we split up our calories across the three macronutrients is important. We need to eat a bit of each of the macros to stay healthy, although the percentage split across the three can vary greatly from person to person depending on their food choices and personal preferences. Some people will eat a relatively balanced split across the three, for example having 40% of calories from carbs, 30% from fats and 30% from protein. While those following a low carb pattern of eating might choose to consume a lower percentage of their calories from carbs (<10%) and get many of their calories from fats (70-80%) and a moderate amount of energy from protein (15-20%). It is important to refer to both to ensure you are taking in an appropriate amount of energy each day. It can happy that by just using macros that you can be drastically under-eating. There is good data available about what targets people should be aiming for good health, so when looking into this information, it is important to work with a registered nutritionist or dietitian to oversee your individual needs, rather than taking it into your own hands starting out.
Another point of importance is that neither of these two energy measures gives information about the nutritional adequacy of the diet being consumed. Technically speaking, you could stay within your calorie requirements and hit your macronutrients eating fast food- which we can all agree would likely lead to some health issues long term. As such, when approaching nutrition, it is important to also be aware that eating a variety of foods from across the food groups is important for you to meet your micronutrients needs (vitamin and minerals).
What you can see here is that it is not a matter of choosing one over the other, if you are looking to look after your health, accounting for both of these measures is important if you are looking to reach your health and training goals. And if you are new to the nutrition game, be sure to get a qualified set of eyes over your nutritional requirements to make sure you are on the right track for your personal needs.