Studies show that eliminating 3,500 calories largely overestimates how much weight someone will lose, as well as how much of that weight will be from fat. Researchers explain that much of the discrepancy is because the way body expends energy (calledmetabolism) changes with weight fluctuations. Plus, as Dr. Foster notes, all of the lost weight comes from a combination of fat and lean tissue, which is mostly muscle. While multipledietandexercisevariables determine how much comes from fat versus muscle, caloric deficits never target fat exclusively. So, when a company or program claims to help with fat loss, that’s a fallacy.
It’s also important to look at the overall nutritional value of a food, rather than calories alone, especially when on a weight loss journey, says Foster. “You can lose weight eating 1,200 calories of anything; but in order to be healthy, the kinds of calories you eat matter.” Foster advises choosing more foods that are high in protein, unsaturated fats, and fiber — and fewer that contain lots of saturated fat and added sugars.
Doing the Math With a BMR Calculator to Make Weight Loss Work for You
To lose a pound, you need to have a good idea of how many calories you burn — that is, use for energy — on an average day. According to the Dietary Guidelines for Americans 2020–2025, the average adult woman expends roughly 1,600 to 2,400 calories per day, while the average adult man expends 2,000 to 3,000. (The Centers for Disease Control and Prevention reports that the average height of an adult American woman is 5 feet 3.5 inches, and their average weight is 170.8 lb. For American men, the average height is 5 feet 9 inches and average weight is 199.8 lb.) Ultimately, age, activity level, body size, and body composition all influence how many calories a person burns throughout each day.
To get a more accurate idea of your daily caloric requirements, you can turn to an online metabolic rate calculator. These determinebasal metabolic rate(BMR), which refers to the number of calories the body burns every day for energy just to maintain basic biological functions. It’s based on your height, weight, age, and sex, according to Diabetes.co.uk. When multiplied by an activity factor (how much you move in a day), you get your daily metabolic rate. This is an estimate of how many calories you actually burn in 24 hours — and how many calories you need to eat every day just to keep yourweightconstant, saysSari Greaves, RDN, of LBS Nutrition in East Brunswick, New Jersey, and the author ofCooking WellHealthy Kids. Some BMR calculators allow you to enter your body fat versus lean mass, a percentage that accounts for a large amount of the variations between any two people’s basal metabolic rates. But, while accurate, these calculators require you to have a tool like calipers (the “fat pinchers” your doctor may use) or a smart scale that estimates your body composition.
Once you know your current daily caloric requirement, you can create your own formula for losing weight. Simply put, as long as you are eating fewer calories than that number, or you increase your daily caloric burn with exercise, you will lose weight, explains Audra Wilson, RD, CSCS, a bariatric dietitian and strength and conditioning specialist at theNorthwestern Medicine Metabolic Health and Surgical Weight Loss Center at Delnor Hospitalin Geneva, Illinois.
For example, you might eat 500 fewer calories, work off 500 more calories through exercise, or do any combination of the two to achieve a deficit of 500 calories. For example, you might choose to eat 250 calories fewer than your daily caloric requirement and then do a workout that burns another 250 calories, she says.
In terms of the 3,500-calorie rule, that means that if you achieve that 500-calorie deficit at the end of each day, you will lose 1 lb of fat in seven days. Unfortunately, that equation tends to oversimplify — and overestimate — losses, so don’t expect to drop that much that fast.
Wilson also cautions that caloric reduction doesn’t always guarantee weight loss. “It is a start, but it’s impossible to simply create a deficit and calculate certainty with weight loss,” she says. “There are many more factors involved, not least of all compensatory measures our bodies take in an effort to maintain homeostasis.”
Still, if you’d like to crunch the numbers that predict your personal weight loss equation (and remember, the word is predict, not guarantee), you certainly can. While the math is complicated, the Pennington Biomedical Research Center in Baton Rouge, Louisiana, one of the top nutrition research centers in the United States, has created aweight loss predictor to help you more closely estimate how much weight you will lose with a given daily calorie deficit. It uses mathematical models based on your age, height, weight, and sex, as well as the size of your daily caloric deficit.
When It Comes to Losing Weight, Easy Does It
The size of your caloric deficit affects how fast you lose weight, with larger deficits leading to faster weight loss.
Yet experts typically agree that losing 2 lb per week is the healthiest and most sustainable pace ofweight loss, Wilson explains. If you are losing more than that in a given week, it is likely that you are significantly cutting into your lean muscle mass. By lowering your metabolic rate, that sets you up to eventually regain all of the weight you lost, and possibly more. When losing more than a couple of pounds per week, you’re also at a higher risk of not having enough macronutrients (protein, carbohydrates, andfat) or vitamins and minerals in your diet, explains Greaves. That’s not because fast weight loss itself deprives the body of nutrients. Rather, when you cut calories to the point of rapid weight loss, your overall food (and therefore nutrient) intake, can be unhealthily low. Astudy published in 2018 in Nutrientsanalyzed three commercialdiet plansdesigned for rapid weight loss, and the authors reported that participants experienceddeficienciesin nutrients such asvitamin D, B vitamins,vitamin E, selenium, and zinc.
However, even with a conservative caloric deficit of a few hundred calories per day, if you are drastically cutting down onprocessed foodsor carbohydrates, you may quickly losewater weight, Greaves says.
Factoring in Diet and Exercise to Shed Unwanted Pounds
Whatever your weight loss goal may be, losing 1 lb should ideally involve both diet and exercise. Pursuing one without the other is setting yourself up to regain the weight later.
“Diet and exercise go hand in hand,” Wilson says. “Diet is more impactful for weight loss in the short term and exercise is more beneficial in the long term to maintain weight loss.”
Not to mention, most people find it easier to cut 500 calories from their diet than to burn 500 calories through exercise. But without exercise, a larger portion of any weight lost will be from lean muscle, meaning that as you lose weight, your body fat percentage could actually increase. In the long term, reduced levels of muscle lower your body’s metabolic rate, meaning that over time your body may actually gain fat, she explains.
One way to stay on target is to track your food using a journal or app. Many allow you to keep tabs on both calories consumed and calories expended through exercise and everyday tasks. According to one study, that can be useful in the management of weight loss.
Again, unfortunately, it’s rare for calorie counters to get things perfect, and they typically overestimate energy expenditure, Wilson says. In fact, someresearchshows that women, on average, underestimate caloric intake by 25 percent.
And if you don’t weigh or measure every ingredient you eat (which can be a challenging undertaking), you can easily think you are in a large caloric deficit when you’re actually in a surplus. That means you’re consuming more calories than you’re burning, thus effectively gaining weight, she says.
Onestudy suggests that every fitness tracker studied incorrectly estimated caloric burn by at least 20 percent.
Greaves adds, “I don’t disregard the value of having a tracker. They can keep you accountable and reinforce healthy dietary choices.My advice, however,is to use these trackers as tools. Track for mindfulness, not for calorie counting.”
Small changes that increase your activity and reduce your caloric intake can lead to slow, steady, lasting weight loss.
Diet and Exercise Tips That Help With Weight Loss
These diet andexercisetips can help you create the daily caloric deficit that will help you lose 1 lb:
Eat whole grains.They fill you up and take longer to digest than thesimple carbohydrates in processed flour or whiterice. Choose whole-grain bread, brown rice, andoatmeal. Whole grains also contain lots of healthyfiber, which may further aid weight loss, according to a wealth ofresearch. According to theU.S. Department of Agriculture(USDA),1 cup of cooked brown rice offers 3.23 grams of fiber, making it a good source.
Think before you drink.Sodas and fruit juices contain tons of calories and added sugar, which can contribute to weight gain and hurt your health in a variety of ways, according to theHarvard T.H. Chan School of Public Health. For example, theUSDAnotes that 8 ounces of fruit punch contains 110 calories and 26 grams of sugar. Simply switching to water (plain or sparkling) can decrease your caloric intake almost effortlessly, she says.
Alcohol is another source of calories to keep in mind. A typical 5-ounce glass of red wine contains about 125 calories, and a 12-ounce beer has around 155 calories.
Eat regular meals.“Skipping meals can cause dips in yourblood sugarand make you more prone to overeating later on in the day,” Greaves says. Stick to three meals and one or two snacks per day. If you tend to forget or miss meals, set reminders on your phone for all meals and snacks.
Do regular strength training.Muscle at rest burns slightly more calories than fat at rest. Increasing your muscle mass helps you lose weight more efficiently. The more muscle you have, the more calories you will burn, even at rest. What’s more,strength trainingwill help ensure that you are losing the bulk of your weight from fat, rather than muscle, Foster explains. Yes, it’s possible to actively build lean muscle while still losing fat.
Break up your workout.Try to engage in at least 30 minutes of moderate-intensity exercise a day for five days a week or 75 minutes of vigorous-intensity aerobic activity per week. Keep in mind thatcurrent federal guidelinesshow that you don’t have to do it all at once for weight loss benefits. For example, you could take a brisk 10-minute walk around the block in the morning, then do a 20-minute strength-training workout later in the day, Wilson says. That way, even the busiest people can squeeze in calorie-burning activities. Top-rated app options for tracking activity includeMyFitnessPal,Simple Workout Log, andFitNotes.
Now that you know what it takes to lose 1 lb of fat, your weight loss plan will be more effective, and you’ll start building the motivation to lose more and more.
Additional reporting byDennis Thompson Jr and Sarah Garone.
