The most important thing for a successful keto diet is to calculate your macros and calories right. Proteins, fats, carbohydrates, calories—getting the wrong amount of any of these components can make your ketosis impossible. Keep reading to learn the only way of calculating your macros!
Step 1: Calculate your basal metabolic rate (BMR)
Calories are your body’s fuel, almost literally. And just like each car burns a different amount of fuel to move, depending on its size, power, and other factors, each person’s daily expenditure of calories is also unique.
To calculate yours, the first step is to define your basal metabolic rate (BMR). This is the amount of calories that your body needs daily to perform its physiologic functions: breathing, pumping blood, keeping its temperature stable, and so on.
Basically, a person’s BMR is the amount of calories he or she would burn by laying 24h in bed, without moving at all. The most important factors that define one’s BMR are sex, age, weight, and height.
You can calculate your BMR using the Harris-Benedict equation:
BMR = 66 + (13.75 * weight in kg) + (5 * height in cm) – (6.8 * age in years)
BMR = 66 + (6.2 * weight in pounds) + (12.7 * height in inches) – (6.8 * age in years)
BMR = 655.1 + (9.563 * weight in kg) + (1.850 * height in cm) – (4.676 * age in years)
BMR = 655.1 + (4.35 * weight in pounds) + (4.7 * height in inches) – (4.7 * age in years)
Example. Jane is a 23-year-old girl weighing 121 pounds. She is 65 inches tall. According to the formula above, Bob’s BMR would be:
BMR = 655.1 + (4.35 * 121 (weight)) + (4.7 * 65 (height)) – (4.7 * 23 (age)) = 1378,85 calories
Let’s round that up to 1380 for the sake of simplicity, and that’s Jane’s basal metabolic rate. So, if Jane would choose to lay in bed all day without doing anything at all, she’d need 1380 calories to stay in her current weight and maintain all bodily functions in proper form.
However, if Jane decides to do something, each movement would burn extra calories - so she’ll have to get more of them from a dietary source.
Step 2: Adjust your BMR for physical activity
If you adjust your BMR for physical activity, you’ll get your total daily energy expenditure (TDEE). To do this, just multiply the BMR you’ve gotten in the previous step by one of the following numbers depending on how active you are.
Mostly sedentary lifestyle - BMR * 1.2
As a rule, this means having a sedentary job with almost no physical exercise or active rest whatsoever. A lot of college students also fall in this category.
Light physical activity (1-2 workouts/week) - BMR * 1.38
People in this category usually have a sedentary job but occasionally exercise or take part in active outdoor games.
Moderate physical activity (3-5 workouts/week) - BMR * 1.55
People in this category exercise regularly and quite intensively, but still have a sedentary job and spend a great deal of each day just sitting in one place.
Heavy physical activity (manual labor and/or 6-7 workouts/week) - BMR * 1.72
The hardcore people. These ones have BOTH an active or physically demanding job AND exercise a lot throughout the week. Alternatively, their exercises may be their main job—like in the case of professional athletes or bodybuilders.
Example: Let’s say that Jane from the previous article is an office worker. According to the numbers above, we have to multiply her BMR (1380) by 1.2 to calculate her TDEE.
Jane’s TDEE = 1380 * 1.2 = 1656 calories per day
This is the amount of calories that Jane would have to get in order to stay in her current weight. Going over that limit would most likely lead to weight gain, while getting less than 1656 would probably lead to weight loss.
But not all calories are equal, especially on the keto diet. Let’s learn how to calculate the macros that would make your daily caloric goal.
Step 3: Calculate your macronutrients
The keto diet in a nutshell is all about getting your calories from the following sources:
Fat - 70-75% of the daily caloric intake (TDEE)
Protein - 20-25%
Carbohydrates - 5%
The main point here is that different macros have different caloric densities. In other words, an ounce of fats and an ounce of carbs are VERY different in terms of calories.
Fat: 9 calories / g
Protein: 4 calories / g
Carbohydrates: 4 calories / g
When you turn the fractions of macros above into tangible numbers, you’ll have a much clearer picture on how to build your keto diet. Let’s do it on Jane’s example.
Example. Let’s say that Jane has decided to follow a keto diet on 70% fat, 25% protein, and 5% carbs. In terms of calories, that would be:
Fat: 70% of 1656 calories = 1656 * 0,7 = 1160 calories
Protein: 25% of 1656 calories = 1656 * 0,25 = 414 calories
Carbohydrates: 5% of 1656 calories = 1656 * 0,05 = 82 calories
Now, remember that protein and carbs give 4 calories per gram and fat gives 9 calories per gram. Let’s turn Jane’s macro calories into tangible weights.
Fat: 1160 calories / 9 = 129 grams, rounded up
Protein: 414 calories / 4 = 104 grams, rounded up
Carbohydrates: 82 calories / 4 = 21 grams, rounded up
And that’s how you can learn your goal macros in order to follow a healthy keto diet. Everything else is pretty straightforward: just check the amount of fat, protein, and carbs in your products and meals - and eat them up without exceeding your daily protein and carb limit.
For most people, this will be enough to reach ketosis in no time. If you find yourself stuck and having trouble with that, make sure to check our guide on the most common reasons and how to deal with them!
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