Calories, those little units of energy you consume, are arguably the most talked-about part of healthy eating and weight loss. The general rule is that if you take in more calories than you use, you’ll gain weight, if you take in fewer calories than you use, you’ll lose weight, and if those numbers are pretty much the same, you’ll maintain your current weight. In reality, it’s a little more complicated than that. Here, experts explain how to figure out how many calories you should eat to lose weight, and why that number isn’t necessarily the most important (or healthy) thing to focus on.
Before we get into how to calculate your calorie needs and intake, let’s talk about a really good reason you may not want to do it. Counting calories can become a slippery slope from conscious eating to disordered eating. Obsessing over what you eat, besides taking all the fun out of food, can lead some to embrace unhealthy habits. If you have a history of disordered eating, doing the math on your caloric intake is not the healthiest idea, and you should absolutely consult your doctor before you make any changes to your diet. And know that there are plenty of other ways to eat healthily that don’t involve math—for more on this, check out this piece on why you don’t need to count calories from a registered dietitian, as well as this piece on how to eat mindfully. Also important to note: weight loss isn’t for everyone, nor should it be. Whether you do or don’t want to lose weight is entirely personal, and in any case your weight is dependent on lots of factors, not just your diet. Your activity level, stress levels, hormones, sleep schedule and more all play a part, and counting calories may or may not be a helpful addition to other habit changes.
If, however, you find that counting calories is a useful tool for keeping you on track with your goals in a healthy way, then the following tips may be helpful.
In order to figure out (roughly) how many calories you should be eating in a day, you need to figure out (roughly) how many you actually need.
Start by getting an idea of your basal metabolic rate (BMR). “The basal metabolic rate is the minimum number of calories your body burns at rest,” Anna Z. Feldman, M.D., an endocrinologist at Joslin Diabetes Center, tells SELF. “This number of calories is required for involuntary functions such as breathing, regulating body temperature, digesting food, and [keeping] your circulation going. Think of this as the bare minimum number of calories you would need to keep your body alive if you were to stay in bed all day.”
Different experts use slightly different equations to figure out BMR. Feldman’s go-to for women is as follows:
655 + (4.35 x your weight in pounds) + (4.7 x your height in inches) – (4.7 x your age in years)
So if you were a 135-pound, 25-year-old, 5-foot-6 woman, your BMR calculation would look like this: 655 + (4.35 x 135) + (4.7 x 66) – (4.7 x 25) = 1,435.
But other experts use a formula called the Mifflin St. Jeor equation. Here it is, courtesy of Brigitte Zeitlin, R.D., M.P.H., C.D.N., founder of the New York-based BZ Nutrition:
(10 x your weight in kilograms) + (6.25 x your height in centimeters) – (5 x your age in years) – 161
Using the same stats as above, your BMR calculation would look like this: (10 x 61) + (6.25 x 168) – (5 x 25) – 161 = 1,374.
As you can see, the results are slightly different, but not by too much. That’s fine, because any BMR calculation you do on your own is just a general guideline, and you shouldn’t stress about pinpointing an exact number. “The actual best way to calculate your BMR is to go into a lab,” Rachele Pojednic, Ph.D., a research fellow at Harvard Medical School and professor at the Harvard Extension School, tells SELF. “They can measure the amount of carbon dioxide you’re expelling and how much oxygen you’re breathing to see how efficiently your body is metabolizing calories,” she explains.
BMR is at the root of the main hard-and-fast rule for safe weight loss: Your calories should never dip below 1,200, according to the Academy of Nutrition and Dietetics. “Most people’s BMR falls above this number, unless they are quite small,” says Feldman. So, in general, most people need more than 1,200 calories per day to keep their various physical systems healthy. What happens if you drop below that number? “When you eat less than 1,200 calories per day, your metabolism can be majorly affected, your muscle mass can start decreasing, and you won’t get the vitamins you need to sustain daily activities,” Jim White, R.D. and spokesman for the Academy, tells SELF. Point is, eating is great for you (not to mention fun), and you shouldn’t cut out too much of it whether you’re trying to lose weight or not.
To figure out how much you should eat for weight loss, you’ve got to factor in your activity.
Now that we’ve calculated how much calories your body burns in order to stay functioning, we need to take into account everything else you do that burns calories including your morning walks and regular Tuesday night yoga classes. To do that you can try the interactive calculator from the United States Department of Agriculture (USDA). This tool incorporates your activity level along with your BMR to give you a more specific number providing you with a rough estimate of how much you should eat in order to maintain your current weight (BMR + activity level).
If you want to lose weight, you’ll need to cut calories from your maintenance mode to see results. “One pound of fat is around 3,500 calories, and safe fat loss is one to two pounds per week,” says White. To lose one pound of fat per week, you’d need a 500-calorie deficit each day. Instead of creating that deficit solely by eating less, White recommends mixing in exercise as well. Beyond taking the pressure off of yourself to curb your eating too much, it’s also just good for your health.
This is a good formula to use as a guide, but weight loss is more than just calories in, calories out. “There are other factors that affect how much weight you will lose and at what rate,” says Feldman. A few of them: your age, because metabolism slows as you get older, your starting weight, because a person with a high one generally sheds pounds quickly, and your lean muscle mass, which can help spur weight loss.
Muscle matters when it comes to weight loss.
Gaining muscle is a great way to get closer to any weight-related goals you may have, and also feel healthier all around. But one thing to keep in mind: Your BMR will increase as you gain muscle. “When you have more muscle, the amount of calories your body needs to regenerate that tissue is significantly increased,” says Pojednic. There’s also the fact that muscle is very metabolically active.That means it’s great at burning calories even when you’re not using it. “Lean muscle tissue burns more calories than fat at rest. That means if you build lean muscle mass while exercising, you will be able to increase your metabolism—even at rest—which will help you with weight loss,” says Feldman.
Don’t freak out if you start strength training and see the number on the scale stay the same or go up. If you’re eating healthily, you’re likely gaining muscle, not fat. Since muscle is denser than fat, you can still see the results you’re after—while also becoming more efficient at burning calories—even if the number on the scale goes up, says Pojednic.
Although calories are important, they’re just one element of eating well.
These experts all agree that counting calories isn’t the be-all, end-all of living your healthiest life, even when it comes to weight loss. “[Counting calories] can become obsessive and makes you feel like you’re on a diet,” says Zeitlin, who doesn’t use the practice with her clients. There’s also the fact that sticking to an exact number means being strict to a point that often isn’t sustainable. Eyeballing portions usually isn’t precise enough, so real calorie counting involves reading labels, buying a food scale, measuring out portions, the whole nine yards. Also, according to an April 2015 report from The New York Times, even official calorie labels can be inaccurate. Plus, if counting calories stresses you out, you could theoretically raise your cortisol levels to the point that it’s harder for you lose weight, says Feldman. If you have a history of disordered eating, even if you’re in recovery, focusing on calories could steer you to dangerous eating patterns.
Being aware of your caloric intake can be helpful, especially if you’re trying to lose weight. But experts recommend focusing more on what you’re eating instead of how much you’re taking in. Calories are useful, but they’re not everything. “When you eat real food—fruits, vegetables, nuts, seeds, whole grains, dairy, and lean meats—the calories take care of themselves because you get full before you consume too many,” says Pojednic. “Specifically, the fiber in the plant-based food and the protein in the animal-based food send signals to your brain to stop eating before you’ve gone overboard.”
So no matter what your health and fitness goals are, being mindful about the food you choose—and listening to your body’s satiety cues—might be the best option overall.
Looking for a new workout? Try this 10-minute plyometric routine you can do at home: