Caloric Deficit: What is it and how to calculate it? Complete Guide 2024

Understanding and correctly calculating your caloric deficit is critical to effective and healthy weight loss. Here we guide you through this process.

What is the Caloric Deficit and when to apply it

Calorie deficit is a nutritional condition in which you consume fewer calories than your body needs to maintain its current weight. It is the fundamental principle behind weight loss: by consuming less energy than you expend, your body begins to use stored fat reserves to obtain the missing energy, resulting in weight loss.

Applying a caloric deficit must be done carefully and at the right time. It is most appropriate when you have weight loss as a goal, but want to do it in a healthy way. It is crucial not to cut calories too much or too long, as this can lead to health problems such as loss of muscle mass, fatigue, nutritional deficiencies, and a slower metabolism.

Before applying a caloric deficit, it is advisable to consult a health professional or a nutritionist. I Ignacio as a sports professional can calculate your caloric deficit if you have doubts about how to do it yourself, and it is as easy as requesting your personalized training program.

Steps to Calculate your Caloric Deficit

1. Calculate your Basal Metabolic Rate (BMR)

BMR (basal metabolic rate) is the amount of calories your body needs at rest to maintain vital functions such as breathing and circulation. You can calculate it using formulas such as the Harris-Benedict or Mifflin-St Jeor formulas.

Mifflin-St Jeor formula (most current): 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

Harris-Benedict formula: For women: BMR = 655 + (9.6 × weight in kg) + (1.8 × height in cm) - (4.7 × age in years)

For men: BMR = 66 + (13.7 × weight in kg) + (5 × height in cm) - (6.8 × age in years)

2. Adjust your BMR with the Physical Activity Level

Multiply your BMR by the factor corresponding to your level of physical activity to obtain your total energy expenditure (TEE). Factors can be:

Sedentary (little or no exercise): BMR × 1.2
Slightly active (light exercise/sports 1-3 days a week): BMR × 1.375
Moderately active (moderate exercise/sports 3-5 days a week): BMR × 1.55
Very active (hard exercise/sports 6-7 days a week): BMR × 1.725
Extra active (very hard exercise/sports and physical work): BMR × 1.9

3. Set your Calorie Déficit Goal

To lose weight, you must consume fewer calories than you expend. A reduction of 500 to 1000 calories per day is generally recommended, resulting in a weight loss of approximately 0.5 to 1 kg per week. However, this number may vary according to your individual needs and goals.

4. Monitor and Adjust Your Caloric Intake

Use your GET and target deficit to determine how many calories you should consume daily. Monitor your progress and adjust caloric intake if necessary, always keeping a focus on balanced nutrition and overall health.

Remember, these calculations are estimates and may vary depending on many factors. It is advisable to consult a health professional or nutritionist for personalized advice and follow-up. I Ignacio as a sports professional can calculate your caloric deficit if you have doubts about how to do it yourself, and it is as easy as requesting your personalized training program.

Practical Example: Woman who is 1.60 m tall and weighs 80 kg.

Mifflin-St Jeor formula (most current): Let's assume this woman is 30 years old and has a moderate activity level (factor of 1.55).

BMR = 655 + (9.6 × 80) + (1.8 × 160) - (4.7 × 30) = 655 + 768 + 288 - 141 = 1570 calories/day. Total caloric expenditure = 1570 × 1.55 ≈ 2434 calories/day.

For a deficit, you could aim to consume about 1934 calories per day (500 calories les).

Consequences of Removing Too Many Calories in a Calorie Deficit

Taking away too many calories in a caloric deficit can have several negative consequences, both for your physical and mental health. Here are some of the most important ones:

Loss of Muscle Mass: When the caloric deficit is too large, the body not only uses stored fat for energy, but can also begin to break down muscle tissue for energy, leading to loss of muscle mass.
Slower Metabolism: A drastic reduction in caloric intake can cause the body to go into “energy conservation” mode, reducing the basal metabolic rate. This means your body burns fewer calories at rest, which can make long-term weight loss even more difficult.
Fatigue and Decreased Physical Performance: With less energy available due to reduced calories, it is common to experience fatigue, weakness and a decrease in physical performance and endurance.
Nutritional Deficiencies: A significant calorie deficit often means you are not consuming enough essential nutrients, which can lead to nutritional deficiencies and related health problems, such as anemia, osteoporosis, and skin and hair problems.
Psychological Problems and Eating Disorders: Restricting calories too much can increase the risk of developing eating disorders and eating-related psychological problems, such as food and weight obsession, anxiety and depression.
Hormonal Imbalances: Extreme calorie restriction can affect levels of important hormones, including those that regulate metabolism, reproduction and mood.
Decreased Immune Function: Insufficient energy and nutrient intake can weaken the immune system, making you more susceptible to infection and disease.
Weight Rebound Effect: Extremely restrictive diets are difficult to maintain over the long term. Many people end up regaining lost weight and even gaining more weight after returning to their normal eating habits.

It is important to approach weight loss in a balanced way, focusing on a nutritious diet and moderate calorie reduction, preferably under the supervision of a health professional.

Calculating your calorie deficit is a key step on the road to weight loss, but it must be done with care and knowledge. Whether through traditional methods or with the help of AI, the important thing is to find a balance that supports your health goals safely and effectively.

Let me know in the comments if you were able to do your personal calorie deficit calculation and what your results were.