All About Macros


What are macros?

Macros, or macronutrients, are required by our body for major processes, including energy metabolism. There are three key macronutrients—carbohydrates, protein, and fat—which are measured in the form of calories (or kcal). Carbohydrates and protein provide 4kcal per gram, while fat provides 9kcal per gram. Each macronutrient plays a specific function in the body for optimal body function and health.

Carbohydrates consist of sugars, starches, and fiber and are categorized as simple or complex carbs. Simple carbohydrates or simple sugars (honey, syrup) are broken down rapidly into glucose, while complex carbohydrates (starches, grains, non-starchy veggies) take longer to break down. Glucose is either used by the body for immediate energy or stored in the liver as glycogen for later use. Fiber’s key role, on the other hand, isn’t to provide energy, but rather to slow the uptake of glucose within the bloodstream and keep our digestive system healthy. The healthiest carbohydrates are rich in dietary fiber or provide a natural source of simple sugar, such as fruit (as opposed to refined sugar). Carbohydrates are best consumed in their natural state, as processed carbohydrates are known to negatively affect blood sugar balance.

Protein is made up of 20 different amino acids, also known as the ‘building blocks’ of protein. There are 11 non-essential amino acids and 9 essential amino acids. Non-essential amino acids are made by the body, and therefore don’t have to be consumed through food. Essential amino acids must come from the diet, and are found in fish, poultry, meat and eggs, along with plant-based protein sources such as lentils, beans, nuts, and seeds. 

Fat is categorized as either unsaturated, saturated, or trans fat. Not all fats are created equal, which is why it’s essential to incorporate quality fats in our diet. As noted by the World Health Organization, fat consumption should primarily come from unsaturated sources, with low intake of saturated fats (10%) and no more than 1% of total energy intake from trans fats [1]. Unsaturated fats originate from plant sources (avocados, nuts, nut butters, seeds) along with fatty fish (salmon, tuna, herring). Trans fats are heavily processed and include partially-hydrogenated oils found in margarines, snack foods, and store-bought desserts. 


Why are they important?

Carbohydrates provide the body with glucose, the body’s primary energy source. They also help to synthesize specific amino acids and optimize our digestive system. Protein supports enzyme function and hormone systems in addition to optimizing lean muscle development through building and repairing tissues. Quality fats are necessary for energy storage, fat-soluble vitamin transportation, hormone regulation, and organ protection. All three macronutrients play a key role in every physiological process in the body, from blood sugar balance and appetite regulation to energy metabolism and immune system function. 

How can they help us lose weight?

Various combinations of protein, fat, and carbs can help us achieve different body composition goals. However, a macro ratio that works for one person may not work for everyone.  These ratios will largely vary depending on a number of factors, including gender, age, resting metabolic rate, and current body composition. This means that our daily individual macronutrient requirements depend on our daily calorie needs (calories obtained from food versus calories expended through exercise). Understanding the function of macronutrients in the body can help sustain weight loss, as it allows us to gain greater awareness of our individual daily calorie needs and goal-specific macronutrient ratio. 

Additionally, understanding the amount of protein, carbs, and fats found in various foods groups can make it easier to stay accountable to a specific dietary goal, such as increasing protein intake or lowering total daily carb intake. However, it is also important to consider food quality and meal timing (i.e. cutting out processed foods and avoiding late-night snacking), as these factors can also have a large impact on the longevity of a specific health or fitness goal. Therefore,  in addition to assessing daily macronutrient needs, it’s essential to consume wholesome, nutrient-dense foods and avoid processed foods and added sugar.  

How do you count macros? What does IIFYM mean?

‘IIFYM’ stands for “If It Fits Your Macros,” which is a dietary program based upon counting macros and calories. Specifically, the daily gram requirement for macronutrients is calculated based on a particular goal, such as fat loss or muscle development. The focus of IIFYM is not necessarily on food quality but rather the total daily caloric breakdown of food (i.e. obtaining an ideal daily macronutrient ratio to optimize energy balance and ratio for a specific goal). 

For example, a daily macronutrient ratio for a female geared for weight loss may include a total daily calorie deficit and a balance of healthy carbs, proteins, and fats. This proportion of macronutrients would largely differ from that of a high-performance male athlete with a goal of increasing muscle mass, as protein intake would be significantly higher.

In order to effectively count calories for a specific goal, it is important to first determine Basal Metabolic Rate (BMR), along with your individual daily macronutrient requirement or total daily energy expenditure (TDEE). BMR refers to the total amount of calories burned at rest (without exercise or exertion), while TDEE refers to the body’s total calorie needs when activity or movement is accounted for. 

The Challenge App is an excellent resource for determining both BMR and goal-specific total daily calorie requirements. The BMR Calculator found within the tracking system of the Challenge App provides a quick and accurate assessment of BMR (based upon individual factors like activity level, body composition, age, and gender). Aside from your TDEE and BMR, you’ll also receive a recommended goal-specific total daily calorie intake geared towards fat loss, muscle development, or overall health. The F45 Challenge App is an effective and easy-to-use resource for not only understanding macronutrients, but also for fine-tuning daily calorie needs to better fit your long-term goal. Check out and download the F45 Challenge App (iOS and Android). 


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