If It Fits Your Macros… Eat It! Part 2

If It Fits Your Macros… Eat It! Part 2

Apr 4, 2017

In Part 1 of this series, I introduced the concept of IIFYM (Flexible Dieting), the different types of macronutrients and how energy is used by the body.

In this article, I will show you step by step how you can calculate your own caloric and macronutrient targets, as well as introduce you to measuring and tracking food.

Calculating Your Daily Macronutrient Allowance

The first thing you need to find out in order to establish a calorie target is how much energy you burn on a daily basis. As explained in the previous article, this is known as your TDEE (Total Daily Energy Expenditure), and it can be calculated through a number of different equations.

Although the Harris-Benedict equation has been quite popular until recently, it fails to account for differences in metabolic activity between lean body mass and body fat.

The Katch-McCardle is accurate but unfortunately not applicable to most individuals, since it requires knowledge of your body fat percentage.

The most recently developed equation, known as the Mifflin St-Jeor formula, has been shown to be more accurate and reliable than the previous two.

Below you’ll find the Mifflin St-Jeor formula for both men and women.

Calculating your RMR/BMR


10 x weight (in kg) + 6.25 x height (cm) – 5 x age (y) + 5


10 x weight (in kg) + 6.25 x height (cm) – 5 x age (y) – 161

  • 1 pound = 0.45359237 kilograms
  • 1 inch = 2.54 centimeters

The result is then multiplied by the appropriate activity factor from the table below:

Example: 135 lb female, 30 years old, 5’6”, full-time secretary (desk job), trains lightly twice week.

(10  x 61) + (6.25 x 168) +(150) – 161

= 1649

Multiply by activity factor: 1.2

TDEE = 1985 calories

Adjusting TDEE based on specific goals

If you are looking to lose weight, you need to be eating less calories than your body requires for weight maintenance. That means, you will be ingesting less calories than your TDEE value.

How much less depends on personal preference. I recommend cutting calories by 200-300 initially, since that gives you more room to adjust down the road if necessary.

If you are looking to gain weight, an extra 200-500 calories above your calculated TDEE will do the job. Any more than that and you are looking at putting on a significant amount of fat as well as muscle mass (since your body can only synthesize a certain amount of muscle at a time, the remainder calories will be converted to fat).

Specific recommendations vary depending on metabolism and individual differences. You will have to play around with it to find your sweet spot.

Now comes the macronutrient breakdown. While specific macronutrient requirements are heavily debated and may differ according to each sport, for the purposes of this article I will outline what I personally believe to be the best for body composition.


Meeting your protein requirements is your number one priority; regardless of whether you are trying to lose fat or gain muscle mass. In fact, when it comes to weight loss, protein intake becomes an even greater concern.

Typically, most people will benefit from 0.8 to 1 gram of protein per pound of bodyweight, although some sources recommend intake of as high as 1.5 g per pound of bodyweight. If you strength train regularly, you will need a higher than average protein intake.

Since unused protein is rarely  stored as body fat, eating a little extra won’t hurt you.

Ex: 135 female should be consuming at least 108 grams of protein per day.


The second macronutrient to be calculated is your dietary fat.

Most people will benefit from a fat intake of anywhere from 0.45 to 0.65 gram per pound of bodyweight.

Ex: 135 lb female will need from 60 to 87 grams of fat daily.


The remainder of your calories will come from carbohydrates.

Let’s take our above example of the 135 lb female.

With a TDEE of 1985 calories…

4 calories x 108g of protein = 432 calories

9 calories x 60 g of fat = 540 calories

That leaves her with 1013 calories to fill up with carbohydrates.

1013 divided by 4 calories per gram of carbohydrate = 253 grams

Her macronutrient breakdown is as follows:

108g P/60g F/253g C, total 1985 calories


In Summary

Calculate your RMR using the Mifflin-St Jeor equation.

Calculate your TDEE by multiplying your RMR by the appropriate activity factor.

Break down your calories into protein, fats and lastly carbohydrate requirements.


Measuring and Tracking Your Food

Now that you’ve got your macros all figured out, let’s put it into practice.

Most people cringe when they hear about regularly weighing and measuring food.

Remember, your goal isn’t to spend the rest of your life counting macros. Initially, it will serve as a tool so that you can see how much of each macronutrient you are actually consuming (as opposed to guessing). Over time, you will be able to guesstimate based on tracking experience. For some people, tracking for a much longer time may be necessary, and that’s ok. You will find what works for you.

Reading Nutrition Labels

By now, I’m sure you’ve looked at enough nutrition labels in your lifetime.

Still, a lot of people don’t fully understand how to digest the information from it.

Take the following label as an example:

The first thing we should note when reading a nutrition label is the serving size. In this case, one serving is equal to 228g of the product, or half a container.

That’s important to keep in mind when you plug in your macros in your daily log. If you eat the full container, you’ll be consuming:

26 grams of fat

62 grams of carbohydrates

10 grams of protein

Foods with a nutrition label are the easiest to track. You simply take 30 seconds to look at the macros and plug them into your daily log.

Note that if you multiply the amount of protein, fats and carbohydrates by their respective caloric value, you will arrive at the total number of calories per serving stated in the label.

In this case, 13 grams of fat x 9 = 117 calories

+  31 grams of carbohydrates x 4 = 124 calories

+   5 grams of protein x 4 = 20 calories

=   261 calories (slightly off due to some inevitable rounding error)

Foods without Nutrition Labels

Tracking food items that don’t have an accompanying nutrition label can be challenging.

The number one thing you can do to ensure accuracy is to be consistent with where you get your information from.

For items such as meat products and produce, I highly suggest using either Google or Nutrition Data, which has a large database of nutritional information for many foods, whether raw or cooked.

The serving sizes offered range from 1 cup to 100 grams. Choose whatever is appropriate and more convenient for you (this will highly depend on the type of food as well).

How to Use a Food Scale

A food scale is a necessary component for accurately tracking macros. You can get one for as cheap as $10, and they last for a long time.

You will need a food scale to weigh items that cannot be measured with a measuring cup, or when it is more convenient to weigh it instead.

For example, many people track peanut butter by the tablespoon.

Although that seems to be more convenient, it also turns out to be more inaccurate, as there is no consistency in what a ‘tablespoon’ size will look like. Instead, weighing the peanut butter ensures you are getting the exact amount you are looking for, without over- or under- estimating it.

TIP: When weighing items such as peanut butter, I place it directly on the food that I am having it with. For example, if I’m making a sandwich, I will put the bread on the scale, ‘zero’ it, and then add the peanut butter directly on top. This takes up less time and dishes.

Measuring Cups

You will also need a measuring cup to measure your food.

I recommend using it for liquids and dry items such as oats and rice.

Note that you may also weigh your oats or rice if you’d like, but in this case using a measuring cup would be a lot more convenient.

Tracking Your Food

When it comes to actually keeping track of your intake, you have the option of using a smartphone app (I recommend Lose It or My Fitness Pal), or you can go old-school with a notebook, a pen and a calculator.

Don’t worry about logging your workouts: this has already been taken into consideration when calculating your TDEE. Plus, these apps give highly inaccurate measures of caloric expenditure during exercise. Stick to tracking your food intake ONLY.


Do I need to track my macros every day, forever?

No. You will need to track your macros until you are sure you can eat within your appropriate caloric range by just “guesstimating”.

Do I need to meal prep while tracking macros?

No, but it is a lot easier than tracking along the course of the day (at least until you have acquired enough experience tracking macros).

What I suggest (and what I personally do), is to meal prep and track macros together. I typically prep for 3 days in advance. So, I will track all my macros for a specific meal (say, chicken and rice for dinner), then split it into 3 equal portions.

That way you don’t have to calculate everything after you have split it, and you know for sure what you’re going to be eating.

Do I need to input sugar separately from carbohydrates?

No. Sugar is the simplest form of carbohydrates, therefore they’re not mutually exclusive. 

What about fiber?


Can I weigh/measure food after it’s been cooked?

You could, but I recommend against it. Meats, for example, tend to weigh less after cooking… so your numbers are going to be off, and over time this error could become significant.

Do I need to track vegetable intake?

No, unless you’re eating loads of high-carb vegetables like carrots, for example.

You do need to track your fruit intake since they’re high in sugar.

What about restaurant foods?

Most restaurants now offer nutritional information with their menus

In the case that they don’t, you’ll have to guesstimate it.

HOWEVER, I highly encourage you do not start obsessing over these things. Instead, have your restaurant meal (on occasion) and stay consistent the remainder of the week.

One meal isn’t going to dictate your progress; consistency is.


Do I really need a food scale? Can I just use a measuring cup instead?

You absolutely need a food scale.



I hope this has been helpful to you, whether you’re new to IIFYM or simply looking for answers to make tracking easier for you.

If you have any questions or comments, shoot me an email at info@trainwithbarbara.com or leave a comment below.

Until next time,



Mifflin, M., St Jeor, S., & Hill, L. A new predictive equation for resting energy expenditure in healthy individuals (1990). The American Journal of Clinical Nutrition. Retrieved from http://ajcn.nutrition.org/content/51/2/241.abstract

Henley, S., & Misner, S. (n.d.). Fats and Cholesterol in the Diet. Retrieved from http://ag.arizona.edu/pubs/health/az1126.html

Nordvist, C. (n.d.). What Are Calories? How Many Do We Need? Retrieved from http://www.medicalnewstoday.com/articles/263028.php

 McDonald, L. (n.d.). Nutrient Intake, Nutrient Storage and Nutrient Oxidation. Retrieved from http://www.bodyrecomposition.com/nutrition/nutrient-intake-nutrient-storage-and-nutrient-oxidation.html

Patel, K. (n.d.). Should one gram per pound be the new RDA for bodybuilders? Retrieved from https://examine.com/nutrition/shouldonegramperpoundbethenewrdaforbodybuilders/?utm_source=insiders&utm_medium=email&utm_campaign=blog032317