A calorie deficit is when you burn more calories than you consume. Research suggests that a 500-calorie deficit may help with weight loss. But this number depends on many factors and is different for everyone.

Calories are the units of energy you get from foods and beverages. Calorie expenditure refers to the amount you expend, or burn, each day. It includes three components:

• resting energy expenditure (REE), which refers to the calories your body uses at rest for functions that keep you alive, such as breathing and blood circulation
• thermic effect of food, which involves the calories your body burns digesting, absorbing, and metabolizing food
• activity energy expenditure (AEE), which refers to the calories you expend during movements, such as exercising, fidgeting, and performing household chores

A calorie deficit is when you consume fewer calories than you expend. Over time, this could lead to weight loss. Conversely, you may gain weight if you consume more calories than you need, known as a calorie surplus.

Other factors may also influence weight fluctuations, such as:

• physical activity
• hormones
• lifestyle habits
• stress
• underlying health conditions
• taking certain medications
• genetics
• sleeping habits

## How do I calculate my calorie deficit?

For most people, a calorie deficit of 300–500 is sufficient to lose 0.5 kilograms (kg) (1.1 pounds) per week. However, this needs to be re-evaluated constantly, especially as you lose weight.

To calculate your calorie deficit, you will first need to calculate your maintenance calories. These are the number of calories your body needs to support energy expenditure.

You can calculate your maintenance calories in a few different ways:

### Calorie calculators

You can use a calorie calculator, like the Body Weight Planner from the National Institutes of Health (NIH). It estimates your maintenance calories based on your weight, sex, age, height, and physical activity level.

### Basal metabolic rate (BMR)

Below are two formulas to estimate your BMR, based on sex assigned at birth:

• BMR for males: 66 + (13.75 x weight in kg) + (5 x height in cm) − (6.8 x age in years)
• BMR for females: 655 + (9.6 x weight in kg) + (1.85 x size in cm) − (4.7 x age in years)

Once you have your BMR, you can then calculate your maintenance calories using the Harris-Benedict Formula:

GroupDays active per weekFormula
sedentarylittle or noneBMR x 1.2
lightly active1–3 daysBMR x 1.375
moderately active3–5 daysBMR x 1.55
very active6–7 daysBMR x 1.725
extra active6–7 days and physical jobBMR x 1.9

### 10-day tracking

For a more precise number, track your calorie intake and weight for 10 days while maintaining the same level of daily activity. You can use a calorie tracking app to track your calories and weigh yourself daily. For an accurate result:

• Use the same scale.
• Weigh yourself at the same time of day.
• Wear the same clothes (or nothing at all).

It’s important to note that your weight may fluctuate day to day by a few pounds due to water weight.

Divide the total number of calories you consumed for 10 days by 10 to find your average daily calorie intake. Then, subtract 500 calories from this number to determine your new daily intake goal for weight loss.

For example, if you find your maintenance calories to be 2,000 per day, your new daily calorie goal would be 1,500.

As you lose weight, your maintenance calories will decrease over time. You’ll need to adjust your calorie intake based on your weight loss goals.

It’s also important to note that a prolonged calorie deficit may affect your metabolism. It may change and slow down to meet your new calorie intake. This can make weight loss more difficult in the end.

## How do I reach a calorie deficit?

You can reach a calorie deficit by consuming fewer calories or increasing your physical activity levels — or both.

Creating a calorie deficit alongside being physically active may be a more sustainable, safe, and effective weight loss method.

### Diet

Eating a well-balanced diet is important to achieving and maintaining a healthy calorie deficit.

The Dietary Guidelines for Americans 2020–2025 suggest that a healthy dietary pattern is key for supporting your calorie needs and reducing your risk of some health conditions, such as cardiovascular disease and type 2 diabetes.

A well-balanced, nutritious diet may include:

Here are some tips that may also help you lower your caloric intake without having to count calories:

• Avoid drinking your calories: Alcoholic and sugary beverages like soda, fruit juices, and specialty coffee drinks can contain many calories. However, calories from these beverages don’t provide fullness. In excess, they can lead to weight gain.
• Limit highly processed foods: The sugar, fat, and salt in highly processed foods make these foods highly palatable and encourage excess consumption. A 2019 study found that people who ate as much or as little as they wanted took in 500 more calories per day on a diet containing highly processed foods, compared with a diet containing minimally processed foods.
• Try healthy food swaps: Many healthy alternatives to everyday foods and drinks may help you reduce your calorie intake. For example, you can make coffee creamer, granola bars, and chips instead of consuming store-bought products that may contain high levels of unsaturated fats, sugar, and salt.
• Eat home-cooked meals: Eating home-cooked meals is associated with better diet quality, an increased intake of fruits and vegetables, lower body fat levels, and reduced risks of heart disease and diabetes.

### Exercise

Weight loss is just one of the many benefits of getting regular physical activity.

The Physical Activity Guidelines for Americans recommend that adults do 150–300 minutes of moderate intensity exercise, or 75–150 minutes of vigorous intensity exercise, weekly.

Moderate intensity exercise may include brisk walking, light bicycling, and yoga, while vigorous intensity exercise may include jogging and fast bicycling.

The guidelines also recommend that adults do muscle-strengthening activities involving their major muscle groups — including the back, shoulders, chest, arms, and legs — at least two days every week.

Muscle-strengthening activities can also help your body prioritize the loss of body fat rather than muscle mass.

### How many calories should you be in deficit?

A calorie deficit of 300–500 calories per day is effective for healthy and sustainable weight loss.

### How do I know if I’m eating in a calorie deficit?

If you’re in a healthy calorie deficit, you shouldn’t be experiencing noticeable signs of hunger, starvation, or energy loss. However, if you’re in too much of a calorie deficit, you may experience some of the following symptoms:

• low energy levels
• rapid weight loss
• hair loss
• mood swings
• starvation
• constipation
• feeling cold

It’s important to talk with a healthcare professional if you experience any of these symptoms related to being in a calorie deficit. They can help you develop a plan to consume more calories.

## Takeaway

A calorie deficit occurs when you consume fewer calories than your body expends. A calorie deficit of up to 500 calories per day is effective for healthy and sustainable weight loss.

Eating a well-balanced diet of whole foods and exercising or getting some kind of physical activity for 150–300 minutes per week are great ways to help you maintain a calorie deficit.

That said, speak with a healthcare professional if you’re unsure about the number of calories you need to eat. They can develop a weight loss program that’s right for you.