Happy Monday! How was everyone’s weekend? I’ve been trying to fight off a cold. Yay…The good news is it hasn’t really hit me that hard. The bad news is it won’t go away.
As promised, here is the first post about how I got started following IIFYM (If It Fits Your Macros). Originally this was going to be one blog post but I realized pretty quickly that it was way too long. So for today, we’re just going to focus on the first step: calculating your daily caloric intake.
Before I get started I want to mention again that I’m not a doctor, nutritionist or certified trainer. I’m only sharing what has worked for me.
Calculating your Daily Calories
The first step with IIFYM is figuring out how many total calories you should be eating per day. This is going to be different for everyone. You want to take into account three things:
- How many calories your body burns per day
- What your goals are (fat loss, maintenance or muscle gain)
- How many calories you’re used to eating
How many calories you burn per day
There are a few different ways to figure out your daily burn. You might have heard this called your “Basal Metabolic Rate” or BMR. There are tons of BMR calculators online, but the common formula is:
Male = 66 + (6.3 x bodyweight in pounds) + (12.9 x height in inches) – (6.8 x age in years)
Female = 655 + (4.3 x bodyweight in pounds) + (4.7 x height in inches) – (4.7 x age in years)
So for me I would do:
655 + (4.3 x 130) + (4.7 x 60) – (4.7 x 29) = 1,360 calories burned per day
From there you want to factor in how much exercise your body gets just through everyday movement. (You’ll also hear this called your TDEE, Total Daily Energy Expenditure). For example, I burned a lot more calories standing all day when I was a teacher than I do now sitting at a desk all day.
- Sedentary (desk job) = BMR x 1.2
- Lightly active = BMR x 1.375
- Moderately active = BMR x 1.55
- Very active = BMR x 1.725
So again for me, I would take:
1,360 x 1.2 = 1,480 calories burned per day
Now this formula isn’t perfect. There are so many factors that will affect your daily burn but this will get you close enough.
For me, rather than use the formula, I go by what my FitBit tells me. On average, it says I burn anywhere from 1,400 to 1,600 calories (without my workouts), depending on the level of activity.
Side note: A trainer once told me to calculate my daily burn by wearing my heart rate monitor for 24 hours. I do not recommend this method. I tried it and my Polar FT7 said I burned 2400 calories. At 5ft nothing this just doesn’t seem right. The calories on a HRM are calculated by how fast your heart beats. But the fitter you are, the slower your heart rate. So according to this method, a person who is also 5ft tall, 130 lbs but solid muscle would have a lower caloric burn than me. Which is incorrect.
Figure out your goals
Now that you know how many calories you burn per day, you want to figure out how many calories to eat.
- To lose fat = eat less calories than you burn
- To maintain weight = eat the same amount as you burn
- To gain muscle = eat more calories than you burn
I’m going to assume that most of us are trying to lose weight. To lose 1 lb. per week, you will need to eat 3,500 calories less than what you burn.
So let’s say you burn 1,800 calories per day.
That’s 1,800 x 7 days = 12,600 calories burned per week
(12,600 – 3,500) / 7 days = 1,300 calories to eat per day to lose 1 lb. per week.
It’s typically not recommended to eat less than 1,200 calories per day. So for me it gets a little tricky.
I burn 1,500 calories per day. To lose 1 lb. per week, using the formula above, that’s only 1,000 calories per day. I can either take longer to lose weight or I need to make sure I burn more than 1,500 calories per day by exercising.
Right now I do the second option. I eat 1,200 calories per day and make sure to burn at least 200 calories through exercise, to bump my daily burn up to 1,700.
How many calories you’re used to eating
So now you know about how many calories you burn per day and how many calories you should eat for your goals. But there is one more thing you should consider.
If you have been eating less calories than you should, do not increase how much food you eat too quickly. You will gain weight.
I made this mistake in the past. About two years ago I started to experiment with calorie counting. I decided to eat 1,400 calories on the recommendation of a trainer. And I gained 10 lbs. in one month!
The issue was my body wasn’t used to food. Even though I thought my anorexia was gone, I was still drastically under-eating. I would routinely skip breakfast, eat a small salad for lunch and never snack. Which roughly came out to 700 calories per day.
When I basically doubled the amount I ate, my body held onto everything thinking I might starve it again in the future.
Before you start IIFYM, I recommend tracking how many calories you consume in one week. Don’t let the number influence what you eat. You are just doing it to find out where your body currently is.
I personally use myfitnesspal.com to track. Feel free to add me as your friend (screen name: painfreekitchen).
If after a week you realize the amount you eat is more than 200 calories less than what you should be eating, you’ll want to slowly increase by 50 calories per week to avoid gaining weight. This is pretty easy by either making your serving sizes a bit bigger or adding in a small snack.
Alright, it’s 9pm now so it’s time for me to head to bed. Let me know if you guys have any questions. For now, your homework if you’re interested in trying IIFYM is:
- Calculate how many calories you burn per week
- Calculate how many calories you should be eating
- Figure out how many calories you typically eat