Counting macros is one of the most popular nutrition tools in the fitness space. It's typically used by those who want to lose body weight or change their composition in some way, with those people plugging their stats into a macro calculator to find out their ideal numerical intake.
Just a quick education lesson for those who don't know what macros are: the word is short for macronutrients, which is the term to describe carb, fat and protein.
'They are called "macros" because they are required in large quantities by the body,' explains Georgia Chilton, senior nutrition manager at Fresh Fitness Food. Unlike micronutrients, like vitamins and minerals, of which you only need milligrams per day, you require tens - if not hundreds - of grams of these macronutrients.
How much you need of each is really personal and depends on many factors, which is why paying attention to them is so important.
‘"Macro split" refers to the proportion of calories you consume of each of the three macronutrients. As with many aspects of nutrition, there is no one-size-fits-all approach to the most optimal split for an individual and it will be dependent on factors such as your lifestyle and goal,' adds Chilton.
Why do macros matter?
Macros make up your caloric intake and eating more or less of certain macros - especially protein - can impact your composition, helping build muscle or lose fat. But your macros matter for so many more reasons than just aesthetics and weight.
'Macronutrient splits can impact our bodies in hugely different ways and this can impact our individual cravings, hunger levels, energy and sleep, to name a few factors. As a result, it is a hugely important determinant of dietary structure,' explains Chilton.
She's shared just some of the ways that macronutrient intake matters for everyone, not just those with physical goals.
Blood sugar control
Measuring your blood sugar has become a buzzy health tool, but you don't need to wear a monitor to know that you never feel that full or have an energy slump after eating simple carbohydrates. These include foods that offer a lot of carbohydrates with limited protein, fat and fibre.
'Ensuring you are eating the correct balance of protein and fat alongside carbohydrates can be helpful as they will help slow the the speed at which carbohydrates in a meal are broken down, thus preventing spikes and crashes in your blood sugar that can lead to fatigue and other health issues,' says Chilton.
Indeed, studies show that pairing other macronutrients, especially protein, with carbs can reduce the glycemic index of foods, meaning they will give you longer-lasting energy and avoid high blood sugar spikes. The next time you grab a 4pm banana for some energy, try pairing it with a handful of almonds or a protein shake to keep you going until dinner.
Athletic performance
We're calling time on the idea that carbs are bad, though. Before a run or high intensity workout we need quick, fast-acting carbohydrates without too much fat or protein that will slow down the release of energy. 'Carbs are the best nourishment for your body a few hours before a run and for races or big events, fueling up a few days before with extra carbohydrate meals - known as carb loading - is also a good idea,' says Chilton.
Again, this is a trial and error moment, but Women's Health expert Renee McGregor has previously recommended aiming for 0.5g-1g of carbohydrates per kilogram of body weight, eaten up to three hours or at least 30 minutes before working out. For a 70kg woman, that looks like 35-70g of carbs before a fast or long run, HIIT session or heavy strength day.
Of course, protein is another huge consideration when it comes to athletic performance. If your goal is to be stronger and lift heavier, 'eating the correct amount of protein is crucial, as in its absence your body will not have the amino acids it requires to build and repair muscle, meaning muscle growth will be impaired,' says Chilton.
For people who regularly exercise, it's best to eat 1.2 to 1.5g of protein per kg body weight per day. For a 70kg woman, that would mean 84-105g of protein per day, spaced out across regular meals.
Hormone balance
'A diet comprising the appropriate macronutrient balance can help to support hormonal balance,' says Chilton. 'Protein and fat are of key importance due to the roles they play in hormone metabolism.'
For instance, studies suggest that protein has the longest impact on ghrelin, the hunger hormone, making it the most satiating macronutrient. For women with PCOS, fat and carbohydrate balance can impact hormones including insulin and eostrogen.
Support energy levels
'Consuming the right balance of macros can help support sustain energy levels and reduce feelings of fatigue,' says Chilton. 'Carbohydrates are the body’s main source of energy, needed for brain and organ function, as well as physical activity. Without carbohydrates, your body struggles to function properly and you often end up feeling run-down and fatigued.'
Again, it's important to balance your carbohydrates with protein and fats for sustained energy, but the key is really eating enough of everything, rather than cutting any macronutrients out of your diet.
Get the most nutrients
The big really impacts the small when it comes to our food intake. 'Muscle mass can affect the metabolism of micronutrients such as iron. Iron is required for the formation of hemoglobin, which carries oxygen in the blood, so enough protein is really important for warding off anemia,' says Chilton.
'Some micronutrients, such as vitamins A, D, E, and K, are also fat-soluble and require dietary fat for absorption. As a result, inadequate fat intake can lead to deficiencies in these vitamins.
'And adequate carbohydrate intake is important for maintaining blood sugar levels, which can affect the metabolism of micronutrients including magnesium. Magnesium is required for various bodily functions, including muscle and nerve function, and inadequate intake can consequentially lead to symptoms such as muscle cramps and fatigue.'
Phew.
How to work out the best macronutrients for health
We have a whole macro calculator right here on Women's Health website so you can work out exactly how many calories you need to eat and work out a healthy macro split. But remember that everyone feels best eating differently: some people thrive off of more carbs while others prefer eating more fats.
"If you feel hungry soon after eating, are hitting a wall during your workouts or want to doze off at your desk at 3pm, it's likely the macronutrient content of your day needs rethinking,' says Chilton.
