• Lauren

Strong 6: S is for Split- How to Calculate your Calories and Macros

What the heck are macro-nutrients?

If you’ve browsed the “fitspo” space on Instagram, you’ve undoubtedly heard the term “macros.” Macro-nutrients, or macros for short, refer to the three most basic sources of calories in the human diet: Protein, Carbohydrate, and Fat.

Why should I care?

Each macronutrient plays a functional role in the body. In very basic terms:

· Protein supports muscle growth and retention. Protein may also increase satiety (the sensation of fullness), which is helpful when dieting. (Paddon-Jones)

· Carbohydrates are the body’s primary energy source (in a non-ketosis state) and also help preserve muscle (World).

· Dietary Fat is also an energy source, it helps absorb vitamins A, D, E, & K, and helps regulate body temperature (Dietary).

Setting macronutrient goals is a great way to optimize your diet, whether trying to maintain weight, lose fat, or gain muscle.

So...how do I do it?

  1. Determine daily calorie budget

  • Use a BMR & TDEE calculator. My personal favorite and the one I’ll use for the example is: https://www.sailrabbit.com/bmr/

  • Enter your age weight, height, sex, and activity level.

  • Determine if you want to lose weight (set lose to 1-2lbs per week), maintain weight (set either lose or gain to “0”), or gain muscle (set gain to .25-.5lb/week if you’re female)

For this example I’ll use Natalie, a 31 year-old woman:

I’ve entered Natalie’s age (31), weight (152lbs), height (calculate to inches here, 5’5” -> 65 inches), and selected gender (F). Body fat % is not required and if you’re unsure, it’s best to leave it blank. Next, we use the Activity Level selector- be as honest as possible here. I like this calculator because it gives more detailed options than some others, but it doesn’t matter a lick if you’re overshooting your daily activity. Natalie works from home and doesn’t get out much. She does not currently exercise. We select the “Working from Home” option.

If we set a conservative weight loss goal for Natalie at -1lb/week, we get a daily calorie target of 1130kcal/per day. That’s not much to work with!

Luckily, Natalie is a smart girl and decides to add exercise to her routine in order to increase her caloric budget. Natalie commits to a light jog around the neighborhood every other morning and thus changes her activity level to “Slightly Active.” Natalie’s new daily calorie target is 1432kcal/day. Still not a ton, but workable for Natalie’s current lifestyle. Natalie wants to lose 20 pounds total and if she sticks to this plan, she could reach her goal in about 5 months!

Now, let’s say Natalie reaches her goal. She now weighs 132lbs, she’s down a few sizes, and she’s feeling fiiiiinnnne. She’s a new woman and decides to celebrate her newfound hotness by getting out on the town a little more. Natalie is dating and eating out at restaurants more frequently. She’ll often enjoy a glass of wine on a date, and have a few cosmos with the girls on Friday night. After the 5 months of dedication she put in, Natalie wants to make sure she keeps the weight off and eats at a maintenance level. To maintain her weight with her jogging routine, Natalie can allot herself 1808kcal/day.

1808kcal/day is easy-peasy on weekdays, but after a weekend of fun, her daily average intake comes up to 1942kcal/day. In order to compensate and still maintain her weight, Natalie decides to stop jogging and do a bootcamp class 4 days per week instead. She can now select “Moderately Active” and sees that her new daily calorie target is 2038kcal/day.

3 months pass and Natalie is still working her butt off at her bootcamp classes and she’s successfully kept the weight off. In fact, she’s down another 2lbs and now weighs 130lbs. One day after class, Natalie’s bootcamp instructor overhears her complaining to a friend about her “squishy” arms. The bootcamp instructor suggests that Natalie start incorporating weight lifting into her routine and recommends that she use a slight caloric surplus to support muscle building. Natalie starts lifting 3 days/week and doing two bootcamp classes per week. She keeps her activity level at “Moderately Active” and sets her weight gain goal to .25lb/week. Her daily caloric budget is now 2149kcal/day.

2. Once you’ve selected a daily calorie budget, it’s time to determine where those calories should come from- AKA macronutrients.


1 gram of Protein = 4 calories

1 gram of Carbohydrate = 4 calories

1 gram of Fat = 9 calories

a. Start with Protein. General rule of thumb is to consume 1 gram of protein per pound of your bodyweight (this is generally an adequate number to build and retain muscle)

  • If we use Natalie’s weight of 130lbs as an example, she would aim to eat at least 130g Protein/day. This would account for 520 calories (130 x 4)

b. Next is Fat. Fat should account for 20-35% of your total calories.

  • Let’s say Natalie wants to shoot for 25% of calories from fat. Using Natalie’s muscle-building caloric budget of 2149kcal, we determine that about 537 daily calories should be from fat intake. This equates to 60g fat (537/9 = 59.7 round up)

c. Carbohydrates can account for the remaining calories.

  • (Natalie’s total daily calories) – (Protein calories + Fat calories) = Calories from carbs

  • 2149 – 1057 = 1092. 1092 (carb calories)/4 = 273g carbs



  • This split is by no means concrete, but a great starting point. Some people enjoy more carbs/lower fat or vice-versa. Don't be afraid to test out different combinations!

Hope this clears up the macro mess for someone out there! As always, feel free to comment below or shoot me a message if you have questions or need clarification! I'm happy to help.


“Dietary Fats Explained: MedlinePlus Medical Encyclopedia.” MedlinePlus, U.S. National Library of Medicine, medlineplus.gov/ency/patientinstructions/000104.htm.

Paddon-Jones, Douglas, et al. “Protein, Weight Management, and Satiety.” OUP Academic, Oxford University Press, 1 May 2008, academic.oup.com/ajcn/article/87/5/1558S/4650426.

World Health Organization, and Food and Agriculture Organization of the United Nations. “Carbohydrates in Human Nutrition.” World Health Organization, World Health Organization, Apr. 1997, www.who.int/nutrition/publications/nutrientrequirements/9251041148/en/.