Counting calories to lose weight seems like a pretty easy approach—after all, it’s simple math. But it can actually be more complex and harder to do than you’d think.

CountingCalories

“Counting calories can be a helpful tool toward helping people achieve weight loss because losing weight is a balance between calories in equaling less than calories out,” says Beth Warren, R.D.N., founder of Beth Warren Nutrition and author of Living a Real Life With Real Food. “However, this is an oversimplified approach that is not as clear cut as it seems.” New York-based R.D. Jessica Cording agrees. “This isn’t for everyone, but for people who do well with structure, it helps them figure out how to spread out intake and can help them stay organized,” she says.

There’s a lot that can go wrong if you take this approach, but it can also work out really well for you if you do it right. If you’re interested in counting calories to lose weight, keep these factors on the back-burner.

Figure out how many calories you actually need

The total number of calories a person needs every day varies depending on a bunch of things, including your age, height, weight, and how active you are. (Obviously, if you’re a half-marathoner, you’re going to need more calories than if you rarely hit the gym.) Estimates range from 1,600 to 2,400 calories per day for adult women, per the Dietary Guidelines for Americans, which is a pretty big range. If you’re not sure where you stand, it doesn’t hurt to check in with a registered dietitian for a consultation—he or she should be able to give you a good goal calorie count to start with. Or, if you don’t have the time or budget for that, Cording recommends looking up an energy estimate calculator online and getting a general idea from that. Just be a little flexible with yourself. “Some people get a calorie number in their head but it might not be the right fit for them—they’re so hungry they can’t stick to it,” Cording says.

Suss out how many calories you're having on the regular now

Once you know your goal daily calories, it’s a good idea to figure out how far you are from that now. Once you have your numbers down, you can try to suss out where you can skrimp from to get your daily calorie count down, Cording says. 

You can be off on your guesstimates

If you’re new to calorie counting, you’re probably not going to know how many calories are in certain foods right away. And, if you’re underestimating how many calories you’re taking in, that can add up. “You might think you’re taking in a lot fewer calories than you actually are,” Cording says. That’s why she recommends trying out an app like My Fitness Pal or Lose It!, which can give you calorie counts. That way, you don’t have to look them up every time you put something in your mouth.

Incomplete information is the worst

Sure, an app or online food database can tell you how many calories are in a bowl of pasta, but things get a little complicated when you have a special sauce on top and some meat thrown in. “It is hard to asses how many calories are in certain recipes, types of foods, products, or restaurant dishes,” Warren says. “You cannot always know them down to the exact number.” And, if you’re trying to lose weight just by this method, it can cause your calculations to be off.

All calories are not created equal

“Calorie counting only tells part of the story,” Warren says, pointing out that quality calories help the body function more efficiently. For example, healthy fats like avocados can fuel the body to burn calories more quickly than simple carbohydrates. “I always focus on quality of foods first and only after that, I match the quantity to take into account a person’s caloric needs for the day,” she says.

You still need to eat healthy

Sure, you could eat your daily calories in ice cream and fries, but that’s not really what you’re going for here. Plus, you’d feel like crap. “If you think about it, your body is going to feel a lot differently after eating 100 calories of gummy candy than 100 calories of avocado,” Cording says. Eating junk food as a good portion of your calories can also leave you hungrier that you’d be if you chose quality foods.

This approach isn't for everyone
Again, counting calories requires you to be organized and on your A-game—and some people love it. But, if focusing on a daily number isn’t your style or feels too rigid for you, this is probably not the best approach for you.