A Number's Game: How to Count Calories (and Stay Healthy)
Disclaimer: First, I am not a doctor or a nutritionist. Second, I do not believe in counting calories as a part of a healthy lifestyle. Our bodies are machines and are well adapted to crave the foods that we need, and to send signals when it has had its share. I believe in a balanced diet and intuitive eating. That said, I feel that tracking intake and expenditure can be a powerful learning tool when you hit a plateau.
Years ago, I counted calories obsessively. Every single calorie in and out was tracked, and it slowly nurtured a very unhealthy relationship with food. I never spoke to a nutritionist, and I relied on what people on the internet were saying about what was considered "healthy" for weight loss. I exercised too much, and I did not eat enough. I look back now and realize that this was the unhealthy way to count calories.
Now here I am, a person on the internet, telling you what I have learned to be the healthy way to count calories. In this post, I will walk you through the process of figuring out how many calories should be consumed based on a person's size, energy levels, and weight loss/gain goals. I will use myself as an example. My goal is to educate in hopes of clearing up any misconceptions about how much one should eat. I see a nutritionist regularly as a part of my wellness routine, and I encourage you to do the same.
First thing: What is a Calorie?
A calorie is a unit of energy.
To get a little science-y, one calorie is the amount of heat energy required to raise the temperature of 1 gram of water by 1 °C at 1 unit of atmospheric pressure. (Huh?) There is some slightly confusing nomenclature involved in all this (calories, kilocalories, small calories, large calories, joules, etc...), but the take-home message here is simple: a calorie is a unit of energy.
In nutrition and fitness, calories are the potential energy available from eating food, and the energy that is used for physical activity. These are the numbers you see on nutrition labels of food, and the numbers that your gym's treadmill spit out at you.
What is Basal Metabolic Rate (BMR)?
Basal metabolic rate, or BMR, is the daily total number of calories needed for your body to perform vital life-sustaining functions.
To translate this slightly, this is the number of calories you need to eat in a day if you were to lay in bed without lifting a finger. It is important to remember that energy is required to do basic things like breathe, digest, pump blood throughout your body, at so on.
Your BMR depends on a few factors, including your sex, weight, height, and age. The formula was first published in 1918 (peep the article by Harris and Benedict here!), but there are many online calculators that make this really easy to calculate. This is the first calculation we will do together. Head on over to this BMR calculator, enter your details, then click "Calculate BMR". Write this number down.
Using me as an example: I am female, 5 foot 6, 128 lbs, and 31 years old. My BMR is 1376.3 calories/day.
How much should you eat on a normal day?
Now that you have your BMR calculated, the next step is to factor in calories burned during daily activity. Depending on how active you are, you will multiply your BMR by the appropriate activity factor to get your daily caloric needs. This is the number of calories needed to maintain your current weight (we will go into weight loss/gain soon!).
Sedentary (little to no exercise): Activity factor = 1.2
Lightly active (light exercise 1-3 times per week): Activity factor = 1.375
Moderately active (moderate exercise 3-5 times per week): Activity factor = 1.55
Very active (hard exercise 6 to 7 times per week): Activity factor = 1.725
Extra active (very hard exercise & physical job): Activity factor = 1.9
Depending on how you are planning to track your intake, there are two ways that you can apply this activity factor. Each method has its pros and cons!
If you want an easy estimate of the number of calories you need to maintain your weight, read the description for each activity level and decide which fits your lifestyle.
Pros of this method: Much simpler calculation. No need to track each workout. Easier for meal planning since your calories are spread out evenly every day.
Cons of this method: If your activity level varies greatly from day to day, spreading your intake evenly each day may leave you hungrier on some days (e.g. if you do a big workout) and more full on other days (e.g. lazy Sundays spent in front of the TV).Using me as an example: I currently exercise 4 times a week and walk to work every day, but my job involves sitting at a desk 5 days a week. I apply the “Moderately Active” activity factor of 1.55.
1.55 x 1376.3 (my BMR) = 2133.3 calories/day to maintain my weight
If you prefer to manually add calories burned from every workout, choose the activity factor that would apply to you if you did not exercise. That way, you won’t be double-counting calories burned from exercise.
Pros of this method: This is a more accurate way of determining your daily caloric needs, since it accounts for the actual exercise that you do. If you do an extra workout or if you skip a workout, it will be reflected in your numbers. You will be eating more on days when your body needs more energy.
Cons of this method: Takes more effort since each activity has to be tracked.This is the method that I use since I use my Apple watch to track things like runs, bike rides, walks, and gym workouts. I chose an activity factor based on sitting at a desk 5 days per week, since the calories burned from my workouts will be factored in separately. I apply the “Sedentary” activity factor of 1.2.
1.2 x 1376.3 (my BMR) = 1651.6 calories/day to maintain my weight on days when I don’t exercise
Factoring in Exercise
If you used method #1 in the section above, you can skip this section. If you used method #2, keep reading.
The next step is to figure out how many calories you burn during exercise. Some brilliant scientists have assigned Metabolic Equivalent of Task (MET) values to every type activity (from running to washing dishes!) to help determine calories burned based on activity, duration, and a person’s weight. Don’t worry, you don’t have to reference this list of 600+ activities (source, and direct link to the list because I know you’re all curious)! There are plenty of resources out there that will do the calculation for you:
Wearable activity trackers - There are a ton of options on the market, with the leaders being Fitbit and Garmin. Ideally, you want a device that uses your heart rate to calculate calories burned. This will give the most accurate data.
Online calculators - Use a website that asks for your weight, type of exercise, and total time spent doing the activity. There is an easy one to use at bmimedical.com.
Apps - Yes, there is an app for that! Most apps will be all-in-one resources that will help you calculate everything I am talking about in this blog post. I recommend that you calculate your caloric needs manually just to ensure that you are confident with the numbers you are working with.
Today I walked to work and back (70 min total), and then went for a 30 minute run. My watch tells me that I burned 240 calories from the walk and 300 calories from the run. Based on the calculation we did in the last section, my caloric intake today should be 1652 (my resting calorie goal) + 240 (walk) + 300 (run) = 2192 calories (to maintain my weight).
If I didn’t go on the run, my intake should be 1652 + 240 = 1892 calories.
Adjusting for Weight Gain / Loss (Calorie Surplus / Deficit)
Everything I have talked about so far has dealt with maintaining weight. In order to lose weight, you need to have a calorie deficit (calories burned is more than calories eaten); in order to gain weight, you need to have a calorie surplus (calories eaten is more than calories burned. Mathematically, all you need to do is subtract or add from the number you calculated above. This is where things can get a little tricky (read: unhealthy) - How much should you add or subtract? Especially when it comes to weight loss, it is incredibly important to ensure that you take it slow.
The greater the calorie deficit, the quicker the weight loss. At the same time, the greater the calorie deficit, the bigger the shock to your body and the more miserable you will be. You will be hungry, irritable, tired, and far more likely to quit! This is how “yo-yo dieting” happens - people set out unreasonable expectations for themselves, stick to a diet for a short period of time, then ultimately fall back into their old habits when they can’t take it anymore.
My suggestion is to start with a 10 to 20% deficit for weight loss, and then go from there. Same goes for weight gain: 10 to 20% surplus of calories. Try this out for 2-3 weeks and see how you feel before making more adjustments. It will feel slow to begin with (don’t expect big changes on the scale), but it will allow you to ease into the process.
For me, a 15% change to calories would mean 1404 calories for weight loss (1652-248) and 1900 for weight gain (1652+248).
Note: A 3500 calorie deficit is needed to lose 1 pound of fat. With a 165 calorie daily deficit, it would take me 14 days to lose 1 lb.
How to Count Calories
Now that you are through the hard part - actually figuring out how many calories you need - you can start to actually count your calories! The most important thing to do when counting your calorie intake is to read the nutritional label, especially the serving size. A serving of oats is a 1/2 cup, but what does 1/2 a cup look like? Until you are comfortable with serving sizes, it may be a good idea to actually measure your food a few times. This will allow you to have a more accurate count of what you are eating.
Be sure to keep track of all the food you eat throughout the day - including that extra handful of cashews you ate while preparing breakfast, or that cookie your coworker gave you at lunch. Everything counts, and your body is keeping track! As I mentioned above, the most popular app for logging calories is MyFitnessPal. They have a huge database of foods, and you can add your own foods and recipes.
Tips for success
Don’t obsess. I cannot stress this enough. It is easy to go a little crazy about the numbers, but remember that all of these numbers are approximations. Food fuels your body and allows you to do the incredible things that you do every day. Your body is literally a machine, and some fluctuations from day to day will not ruin your progress. Try to keep consistent, but don’t freak out if you’re off one day.
Adjust if needed. If you find that you have no energy and are constantly hungry, increase your intake a little until you are comfortable. If you find yourself overeating at night, this is a sure sign that you are not eating enough during the day. Keep your eye on the long-term goal of hitting your goal weight and maintaining it!
Focus on whole foods. This entire post has focused on calories without any mention of the quality of foods that you eat! I am a huge advocate for eating whole, unprocessed foods as the key to a healthy lifestyle - but this is a topic for another blog post!
Treat yo’self. I always allow myself one day of eating whatever-the-heck-I-want. I still listen to my body’s hunger and fullness signals, but these planned days of freedom make it easier to stick to my plan the other 6 days a week.
Still confused? Feel free to send me a message and I’d be happy to help!