A calorie deficit is when the number of calories consumed is less than the number of calories burned in a day, causing the body to use its fat stores for energy and leading to weight loss.

Maintaining a calorie deficit involves controlling the number of calories in your diet in addition to engaging in regular physical exercise, which can help you achieve the best weight loss results as well as maintain your current weight.

While a calorie deficit is a good tool for weight loss, this type of diet should only be done under the supervision of a registered dietitian who can help you maintain a healthy, well-balanced diet and avoid nutritional deficiencies.

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Achieving a calorie deficit requires limiting caloric intake and engaging in regular physical exercise.

Step 1: Calculating a calorie deficit

Calculating a calorie deficit involves figuring out the total amount of energy the body spends in a day, including calories needed to support basic functions like breathing and heart rate as well as the energy spent during daily activities like working and exercising. This is the number of calories needed to maintain your current weight.

Next, subtract your daily calorie deficit goal from the number of calories necessary to maintain your current weight. For example, if your daily calorie requirement is 2000 calories and your deficit goal is 500 calories, your daily calorie goal will be 1500 calories (2000 – 500 = 1500). Reducing daily calories by 500 can result in a weight loss of about 0.5 kg (1 lb) per week.

To lose weight, a daily calorie deficit of between 250 and 1000 is recommended. However, calorie deficit goals will vary based on starting weight, goal weight, sex, BMI, the duration of the diet, and the number of calories burned per day.

How to calculate your personal deficit

To calculate your own calorie deficit, it is first necessary to determine your Basal Metabolic Rate (BMR), which reflects how many calories the body uses at rest. One widely used formula is the Mifflin-St. Jeor equation:

For women: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
For men: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5

Once the BMR is calculated, it is multiplied by an activity factor (e.g., 1.2 for sedentary, 1.55 for moderately active) to estimate the Total Daily Energy Expenditure (TDEE). Subtracting 500–750 calories from this number typically results in gradual and sustainable weight loss.

Step 2: Engaging in regular physical exercise

While diet can make it easier to achieve a calorie deficit, practicing regular physical exercise is also recommended. This is because the combination of diet and exercise yields better weight loss results in addition to helping maintain your current weight.

A person weighing 50 kg (110 lb) burns about 600 calories per hour running on a treadmill, while someone weighing 80 kg (175 lb) burns 1000 calories with the same activity. This is because a higher body weight requires more effort during exercise.

Some of the best exercises to lose weight include aerobic exercises like swimming and dancing as well as resistance training like weight lifting, Pilates, and calisthenics.

Common pitfalls and mistakes

Some common mistakes when trying to create a calorie deficit include extreme calorie restriction, which can slow down metabolism and cause muscle loss, and overestimating calories burned during exercise. Others may fail to consume enough protein, which is essential for preserving muscle mass during weight loss. These errors can hinder results and negatively affect overall health.

Foods to include

When following a calorie deficit diet, it is important to choose healthy, natural foods such as:

Fruit, like apples, pears, papaya, oranges, pineapple, lemons, and grapes;
Vegetables and leafy greens, like tomatoes, zucchini, squash, cabbage, lettuce, and okra;
Whole grains, like brown rice, whole grain bread, oats, and whole wheat pasta;
Lean protein, like fish, chicken, eggs, and tofu;
Legumes, like beans, lentils, chickpeas, and soy;
Low fat dairy, like plain fat-free yogurt, low fat cheese, and skim milk;
Healthy fats, like olive oil, linseed oil, and avocado;
Root vegetables, like potatoes, cassava, and sweet potatoes;
Nuts and seeds, like sunflower seeds, pumpkin seeds, chia seeds, cashews, and Brazil nuts.

It is also recommended to drink lots of fluids, including water and unsweetened tea.

Does it matter what foods you eat in a deficit?

Although the number of calories is important, the quality of the foods consumed also plays a role in weight loss success. Diets that include protein-rich foods, whole grains, and healthy fats tend to provide greater satiety and help maintain lean body mass. Foods with a higher thermic effect, such as protein, also require more energy to digest, slightly increasing daily calorie expenditure.

Foods to avoid

Foods that should be avoided during a calorie deficit diet include:

Sweets, like ice cream, soda, cookies, cake, and chocolate;
Cured and smoked meats, like bacon, linguiça, mortadella, salami, and prosciutto;
Foods high in fat, like french fries, fast food, hamburgers, and pizza;
Refined grains, like white bread, pasta, and white rice;
Ready-made condiments, like salad dressing, mayonnaise, and ketchup.

In addition, it is advised to avoid alcoholic beverages and fruit juices, as these beverages do not keep you full and can lead to weight gain.

When calorie deficits aren’t safe

A calorie deficit may not be safe for everyone. It should be avoided by children, adolescents, pregnant or breastfeeding women, older adults over 65 years, and people with certain medical conditions such as eating disorders, type 1 diabetes, or severe infections. Signs of an unsafe deficit include fatigue, dizziness, irregular menstruation, mood changes, hair thinning, or immune suppression.

Meal plan

The following table is one example of a 3-day meal plan for a calorie deficit diet:

Meal	Day 1	Day 2	Day 3
Breakfast	1 cup of coffee (no sugar) + ½ whole wheat roll with 2 slices of low fat cheese	1 cup of rosemary tea + 1 crepe made with tapioca flour, egg, and ricotta	1 cup skim milk + 1 omelet made with 2 eggs, tomato, and oregano
Morning snack	1 baked apple with a pinch of cinnamon	1 banana with 1 Tbsp oat bran	1 pear + 2 Brazil nuts
Lunch	1 stewed chicken thigh with 2 Tbsp okra + 2 Tbsp beans + 1 side salad of lettuce, tomato, and watercress seasoned with 2 tsp olive oil + 1 orange	1 grilled fish fillet + 3 Tbsp cabbage sauteed in 2 tsp olive oil + 2 Tbsp brown rice + 3 Tbsp black-eyed pea salad with tomato and onion + 1 kiwi	150 g (5 oz) grilled tofu + 1 cup whole wheat pasta with homemade tomato sauce + side of chickpea salad with cucumber, tomato, onion, and cilantro seasoned with 2 tsp olive oil + 6 strawberries
Afternoon snack	1 plain fat-free yogurt + ½ banana (chopped) + 1 Tbsp sunflower seeds	1 smoothie made with ¼ of a papaya and 150 mL (5 oz) skim milk or plant-based milk	Pate made with plain fat-free yogurt, tuna packed in water, oregano, and salt + 3 whole grain crackers
Dinner	1 omelet made with 2 eggs, spinach, tomato, and onion + side of cooked broccoli, cauliflower, and carrots	1 large salad made with shredded chicken, lettuce, arugula, tomato, grated carrot, and cucumber seasoned with 2 tsp olive oil	1 serving vegetable beef soup made with beef, squash, cabbage, tomato, leeks, onion, and zucchini
Evening snack	1 cup camomile tea + 6 grapes	1 cup lemon balm tea + 1 tangerine	1 cup lavender tea + 1 slice of melon

The portions and types of foods included in this meal plan will vary based on age, level of physical activity, and individual health status. For this reason, it is recommended to consult a registered dietitian who can perform a full evaluation and develop a personalized meal plan that meets your individual nutritional needs.

Long-term vs. short-term deficits

In the short term, calorie deficits can lead to rapid weight loss, especially from water and glycogen stores. Over time, however, the body may adapt by reducing metabolic rate and increasing hunger hormones, making weight maintenance more difficult. Studies show that gradual, sustainable deficits are more effective for long-term success than extreme or short-term diets.

Calorie Deficit: How to Calculate Yours + 3-Day Meal Plan for Weight Loss