The Skinny on Macronutrient Diets: What to Know About the Benefits, and the Pitfalls


Macronutrient diets can be effective, but also require a lot of calculations and can lead to disordered eating behaviours if people aren't careful while doing them. Photo: Arx0nt/Getty Images

Macronutrient diets — once the domain of professional athletes and bodybuilders — are making their way into the mainstream and being adopted by people looking for a way to transform their body alongside an exercise program.

Unlike the high-fat, low protein and super-low carb Keto diet, a macronutrient-focussed diet doesn’t demonize a particular food group or food (although it’s safe to say anyone wanting to drop a few pounds isn’t going to regularly wolf down a Big Mac and large fries). Concentrating on macronutrients also takes the focus off of counting calories, and shifts it to achieving the right daily balance of the three macros: carbohydrates, fats and proteins — all essential elements that give your body the energy it needs to function properly. Micronutrients, on the other hand, are mostly vitamins and minerals.

Age, gender, activity level and overall health — as well as your specific fitness goals — will determine how many calories you need to consume and what percentages should come from each group. Older adults and people wanting to build muscle, for example, have higher protein requirements.

Veronica Rouse is a registered dietitian at University Health Network’s Cardiovascular Prevention and Rehabilitation program in Toronto. She says no diet should be undertaken without first consulting a medical professional because of the variables that need to be taken into account, including any chronic diseases or other health issues a person might have.

She also shies away from calorie counting and instead prefers to count the number grams of carbohydrates, fats and proteins a person is consuming every day.

“What I usually teach my clients is to look at the food groups on your plate. And usually, if you have half your plate as vegetables, quarter of your plate as protein and a quarter of your plate as whole grains, then you’re having that macronutrient diet that has that nice balance we’re aiming for to maintain our overall health and our daily energy needs. And, if individuals are overweight, usually eating this way will help them lose weight.”

One common baseline that often comes up is a breakdown of 40 per cent carbs, 40 per cent protein and 20 per cent fat. But someone who is exercising for one or two hours a day and looking to lose weight might amp up the amount of protein (needed for building muscles) and lower the amount of fat. Something to also keep in mind is that protein is satiating, so a meal of just carbohydrates and fat alone would likely leave us hungry an hour later. But if we combine it with fat and protein, we’re more satiated and wouldn’t be hungry again for another four or five hours. And while it isn’t necessary, Rouse says, ideally, each meal should contain all three macros.

“A diet focussed on heart health, or brain health would be more fat. If you’re on a vegan or vegetarian diet, you’re likely getting the upper end of the carbohydrates,” says Rouse. “So, the percentages of calories from carbohydrates, we wanna be between 45 to 65 per cent. For fat, we wanna be between 20 and 35 per cent. And for protein, 10 to 35 per cent.”

Needless to say, undertaking this kind of diet wouldn’t be possible without the use of calculators like MyFitnessPal, as well as a good food scale. That’s because some foods, like chicken, for example, contain both protein and fat.

But some health experts worry that the need for precise calculations and the necessity of weighing out each of your food groups down to the exact gram, could contribute to disordered eating behaviours (and cause people to overlook the importance of micronutrients). That’s why Rouse encourages her clients not to be regulated by external food, like the number of grams or calories, and instead tune into their internal signalling and being more mindful of what they eat.

“So if you have your portions of the different macronutrients, then your body will tell you when you’re full and you’re satisfied and then you can stop eating. If you’ve ever seen a baby eat, they usually don’t finish what’s on their plate because they have these internal signals just like we do. But they listen to them, whereas we have learned to override them. So, it’s a matter of having the right macronutrient distribution and then also responding and listening to our body and what it’s trying to tell us.”


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