In its most basic definition, a calorie is a unit of energy. Whether you’re sitting on the couch or training for a triathlon, everything you do requires energy. Energy can come from the calories you eat or the calories stored in your body.
Eating more calories than your body needs over time ultimately leads to weight gain while eating below your calorie needs results in weight loss.
A calorie deficit occurs when the number of calories you eat is less than the number of calories you burn. Therefore, creating a calorie deficit over time will help you lose weight.
According to the 2020–2025 Dietary Guidelines for Americans, the daily recommended caloric intake for adults can range from 1,600 to 3,200 calories per day.1
More specifically, the recommended calorie range for women is anywhere from 1,600 to 2,400 calories per day. For men, the amount is somewhat higher, ranging from 2,200 to 3,200 calories per day.
However, your individual calorie needs are based on a variety of factors, including your age, sex, general health, body size, height, activity levels, body composition and health goals.
One way to calculate your calorie needs is to use a prediction equation such as the Harris Benedict, Mifflin St. Jeor or Katch-McArdle to determine your basal metabolic rate (BMR). Your BMR is the number of calories your body needs to perform basic physiological functions like breathing, digesting, and blood circulation.
Here’s an example of how to calculate your estimated basal metabolic rate using the Harris-Benedict formula.2
For women, the following BMR formula is used:
655 + (4.35 × weight in pounds) + (4.7 × height in inches) − (4.7 × age in years)
For example, if you weigh 140 lbs, are 5'4" height, and 40 years old, your BMR is 665 + (4.35 × 140) + (4.7 × 64) − (4.7 × 40) = 1,376.8 calories.
This means that you would need a minimum of 1,377 calories to perform basic functions as part of your daily life.
For men, the following BMR formula is used:
66 + (6.23 × weight in pounds) + (12.7 × height in inches) − (6.8 × age in years)
For example If you're 180 lbs, 5'10" tall, and 43 years old, your BMR is 66 + (6.23 × 180) + (12.7 × 70) − (6.8 × 43) = 1,784 calories.
Your BMR is the number of calories you burn per day regardless of what you do. You’ll also burn calories with normal daily activities like bathing, walking, typing, and standing.
Once you know your BMR, you can use that number to calculate your recommended daily intake to maintain your current weight.
The following calculations will provide an estimate of your recommended calorie intake:
- Little to no exercise: BMR × 1.2
- Light exercise (1-3 days per week): BMR × 1.375
- Moderate exercise (3-5 days per week): BMR × 1.55
- Heavy exercise (6-7 days per week): BMR × 1.725
For example, if your BMR is 1,376.8 calories, and you live a sedentary lifestyle, you would need to eat roughly 1,652 calories (1,376.8 x 1.2) to maintain your current weight.
However, if you’re looking to lose weight, you’ll need to create a calorie deficit to help your body burn stored fat for fuel.
The dotFIT Program automatically calculates the daily number of calories you burn and how much to eat to achieve your goal, whether it’s weight loss, muscle gain or improving athletic performance.
Once you know how many calories you need each day, you can create a calorie deficit.
One pound of body fat contains around 3,500 calories. If you want to lose 1 pound of fat in a week, you would need a deficit of 3,500 calories, or 500 calories per day.
However, it’s recommended that you shoot for a weekly weight loss rate of 1-2 pounds a week if you’re overweight or obese, and up to half a pound a week if you’re not overweight.
There are three ways to create a calorie deficit, which include eating fewer calories, burning extra calories by increasing activity, and combining the two.
Eating Fewer Calories Than You Burn
After calculating your daily calorie needs, you’ll have a rough idea of how many calories you need to maintain your current weight. Eating fewer calories, but ideally more food, will create a calorie deficit that can help support your weight loss effort while managing hunger.
Ways to reduce your caloric intake but increase the volume of food you eat include eating more fresh fruits, vegetables, and whole grains, drinking more water, eating lean protein, and reducing your intake of ultra-processed “junk” foods and sugar sweetened beverages like regular soda, juices and coffee drinks.
Another evidence based strategy to reduce calories is to replace 1-2 of your normal meals or snacks with a protein rich meal replacement shake or smoothie. Doing so has been shown to accelerate weight loss and support weight loss maintenance. The dotFIT LeanMR was designed specifically for this reason and includes added fiber, which slows digestion and helps increase the feeling of fullness, thus managing hunger levels.
Increase Your Physical Activity
Increasing your daily physical activity can include intentionally exercising more, and also adding more movement into your daily lifestyle. Tracking and increasing your daily steps is an effective method for increasing your daily calorie burn. For example, taking the stairs rather than the elevator at work, parking far from an entrance when running errands, or doing squats while listening to a podcast.
A Combination of Eating Less and Exercising
The most effective way to create a calorie deficit is to combine eating fewer calories and increasing your activity level. Research has shown that this technique can create sustainable weight loss more successfully than just implementing one method.3
For example, if you reduce your calorie intake by 200 calories per day and burn 300 calories per day through your workout, you could lose approximately 1 pound per week.
The Problem with Eating Too Few Calories
Many weight-loss diets encourage people to drastically reduce their calorie intake. While the bigger the calorie deficit, the more weight you’ll lose, eating too few calories can prevent long-term success and may even impact your health.
It’s Not Sustainable
Creating large calorie deficits can lead to short-term weight loss. However, they are generally not sustainable as people understandably become hungry, tired, and burnt-out.
Eating too few calories can lower your metabolism, which according to research, may persist long after you end your low-calorie diet.4
Can Lead to Muscle Loss
Eating fewer calories than what your body needs can promote both fat and muscle loss.
One way that calorie-restricted diets can slow your metabolism is by causing muscle loss. Overweight and obese individuals can afford to lose weight faster in the initial period whereas lean and normal weight individuals tend to lose more muscle with aggressive weight loss. This is exacerbated if your low-calorie diet is also low in protein and not combined with resistance training and proper multivitamin and mineral supplementation.
Can Lead to Nutrient Deficiencies
Eating too few calories may lead to nutritional shortages and even deficiencies, particularly if the foods you choose aren’t high in vitamins and minerals.
For example, following a low-calorie diet does not provide adequate amounts of iron, folate, vitamin B12, vitamin D, and omega-3 fats, which can lead to irritability, fatigue and compromise the immune system.
Summary
While it may be tempting to create a huge maximum calorie deficit when trying to lose weight, this approach can often sabotage your efforts.
In general, a calorie deficit that exceeds 1,000 calories per day can negatively impact your health and set the stage for weight gain down the road.
Slow, steady, and sustainable weight loss is achieved through a lifestyle that supports sustainable eating habits and a consistent, enjoyable exercise routine.
