There's an actual science to cutting calories for weight-loss success. Use it to your advantage.
Photo: Getty Images/Chris Ryan
To lose weight, you need to cut calories. Sounds easy, but there's more to this age-old weight-loss wisdom than meets the eye. After all, if you're not smart about how you cut calories, you'll wind up starving (read: hangry) and unable to sustain your diet long enough to budge the scale. And if you've added exercise to your weight-loss plan, you need to know how to eat just enough to fuel your workouts without going overboard in the process.
Of course, you can always use exercise as your main weight-loss strategy, but it's typically easier to simply consume less energy than try to burn it off. "The idea that diet is a more important element for weight loss isn't necessarily because the calories from your diet are more significant, it's just that it's easier to target," says Rachele Pojednic, Ph.D., assistant professor of nutrition at Simmons College and former research fellow at the Institute of Lifestyle Medicine at Harvard Medical School.
Let's put it this way: You can run for a solid hour to create a 600-calorie deficit, or you can just cut that jumbo muffin from your diet in the first place. Either approach can lead to weight loss; it's just a matter of which is easier to manage both physically and mentally. "At the end of the day, [weight loss] is a math equation," Pojednic says. (Related: 7 Weird Things That Can Lead to Weight Gain)
To cut through the confusion, we tapped three experts to show you exactly how to slash calories for weight-loss success.
A Word on Food Tracking
When cutting calories, you'll be far more successful if you count 'em as you go. But while calorie counting often gets a bad rap, it's key to weight loss for a few reasons.
For starters, counting calories keeps you accountable. "If you need to write down and acknowledge the 400-calorie cupcake you have with your afternoon chai latte, you're more likely to make a healthier choice," says Pojednic.
In addition, chances are you underestimate just how many cals are in your go-to breakfast burrito, post-workout smoothie, or afternoon cookie (don't worry, we all do it). Logging your food will give you a better handle on exactly how many calories you're consuming, which is critical if your goal is weight loss, says Kristen F. Gradney, R.D.N., director of nutrition and metabolic services at Our Lady of the Lake Regional Medical Center and spokesperson for the Academy of Nutrition and Dietetics.
When using food tracking apps, manually enter your food items when possible to ensure accuracy, Gradney says. Many apps even allow you to scan barcodes making tracking easier than ever. Pojednic recommends MyFitnessPal and the United States Department of Agriculture's (USDA) SuperTracker.
Before You Cut
But before you start slashing calories left and right, you need to figure out how many calories you need per day just to maintain your weight. You can do this by figuring out your basal metabolic rate (BMR), or the number of calories your body burns at rest. Your BMR is determined by a host of different variables, including sex, age, height, muscle mass, genetics and even the weight of your organs. And according to a review in Medicine and Science in Sports and Exercise, your BMR is responsible for a whopping 60 to 75 percent of your total daily caloric expenditure, while physical activity and digestion account for the remainder.
The best way to get an accurate BMR number is to visit a doctor, nutritionist, or fitness facility for an indirect calorimetry test to measure your oxygen consumption. But FYI, these tests can cost $100-plus, according to Marie Spano, C.S.S.D., C.S.C.S., sports nutritionist for the NBA's Atlanta Hawks. For a woman on a budget, your quickest, easiest option is to plug your height, weight, and current activity level into this interactive calculator from the USDA.
Once you have your daily caloric estimate, Spano recommends subtracting no more than 500 calories to get your new daily total. Just keep in mind, this total is a starting point. Feel free to adjust if you find you need fewer—or more—calories than you're currently allotted. If you slash calories too low, you may lose weight initially, but you'll risk some unpleasant side effects: headaches, moodiness, and low energy, Pojednic says. Not to mention, calories are what fuel your workouts and recovery. So, if you find you're struggling with your current calorie allotment, don't be afraid to tinker with it until you find a sustainable total. Otherwise, you'll sabotage your weight loss later on. "Typically you end up overcorrecting after you've lost the weight and put it all back on. Or more," Pojednic says.
Just keep in mind that once you start dropping pounds, your daily calorie needs will also drop, Spano says. This is because simply put, smaller things require less energy to power them. Think of it this way: Your smartphone likely uses less juice than your laptop or tablet. So, if you're using the USDA calculator or another online tool, recalculate your daily caloric needs once you lose 10 pounds. This way, you don't eat more calories than you need. If you coughed up cash for an in-office test, wait until you've lost 20 pounds or more to get re-tested, and use an online calculator to tide you over until then. (Related: 6 Tricks for Preventing Weight Gain and Staying at Your "Happy" Weight)
Making the Cut
Once you're ready to cut calories, start by slimming your bevvies, Gradney says. To avoid feeling deprived, pick calorie- and sugar-free versions of your favorites. From there, cut high-cal condiments like mayonnaise, and top your salads with vinegar-based dressings instead of creamy ones. You can also reduce calories by subbing in fiber-rich fruits and veggies for your midafternoon snack, which offer the added benefit of keeping you fuller longer. Your best options include apples, bananas, raspberries, dark greens like spinach, carrots, and beets.
Spano also recommends cutting fat before carbs, especially if you're a runner or HIIT-lover. "You need a certain amount of carbohydrate for high-intensity exercise," she says, but adds that you can cut back on carbs if you have a light workout planned or the day off. You'll want to stick with general dietary recommendations, which suggest approximately 130 grams of carbohydrates per day. Limit saturated fat to less than 10 percent of your daily calories.
And (no surprise here), while you're cutting, make sure the calories you are getting aren't coming from junk foods. Swap out high-fat, high-sugar foods like muffins, chips, and processed meats for nutritionally dense options like leafy greens, whole grain breads, and lean protein. This will give you the most nutritional bang for your buck, helping you fill up while you slim down. (Related: This 30-Day Clean-ish Eating Challenge Will Reset Your Diet for the New Year)
When to Get Help
Okay, so you've calculated your daily caloric needs and dutifully tracked your food intake to stay within a 500-calorie deficit. What if, after weeks—or even months—of effort, the scale hasn't budged? (Ugh!) According to Pojednic, if you're sticking to a 500-calorie per day deficit, you should be on track to lose about 2 pounds per week. So if you haven't seen any progress after 30 days, it may be time to enlist the help of a physician or registered dietitian, Pojednic says.
According to Spano, it's not uncommon for people to calculate their calorie needs incorrectly, overestimate how many calories they're burning through exercise, or underestimate how many calories they're eating. A physician or registered dietitian can help pinpoint your problem, and advise new strategies to get you on track (think increasing exercise or meal frequency, or re-evaluating your calorie-counting method).