Caloric Intake: What are my needs?

How can you improve your body composition while improving your athletic performance? Is it possible to lose weight without always feeling hungry or tired? Yes, you can! Remember that the ultimate goal is to be healthy, not just look healthy. Unfortunately, many diets restrict caloric intake, which can lead to many side effects.

Instead of feeling fit and healthy, you will accumulate injuries and fatigue. So today I will present you with the exact calculation of the calories you need in your diet for optimal performance. This will help you avoid the side effects that can occur with caloric restriction.

Energy Balance

We already know the principle of energy balance. If you are in balance, it indicates that your caloric intake is equal to your energy expenditure. So you eat as much energy as you spend. In addition, we also know that each person has a basal metabolism. This represents the number of calories the body needs at rest to perform basic functions. The basal metabolic rate is different for everyone, but remember that you should never follow a diet where you consume fewer calories than your metabolic needs.

From the basal metabolic rate, a person’s total energy expenditure could be calculated using physical activity coefficients. Today, many smart watches also give you the total number of calories you burn during the day. So these are no longer estimates.

It used to be the way the body’s needs for weight loss was calculated. For example, if you spend 2000 calories, then you would only need to subtract 250-500 calories a day from your diet to lose weight. With a caloric intake of 1500-1750 in your diet, you were guaranteed to lose weight during the week. In addition, your diet contained more calories than your basal metabolic rate and therefore the harmful effects of restriction were avoided.

However, there is a gap in this model. If you are inactive, this method will work for you. However, if you workout regularly, it may not be enough to prevent you from being constantly tired or noticing a decrease in your performance.

Energy availability

Nowadays, a new concept has appeared to improve this model. We now talk about energy availability instead of energy balance.

Availability of energy is a recent concept in sports nutrition that equals the energy required for health more than the energy needed to achieve energy balance. It is therefore no longer a question of finding a balance between energy intake and expenditure. It is rather about meeting the energy requirements for the proper functioning of the body.

Available energy is the caloric intake remaining for the body after subtracting the energy expended by physical activity. Someone who would have 2000 calories in their diet, but spends 800 calories on a daily basis, has only 1200 calories of energy available.

Health or performance problems occur gradually during the reduction of available energy. It is a continuum and not a precise limit. Low available energy is not synonymous with negative energy balance or weight loss.

If a reduction in available energy is associated with a reduction in basal metabolic rate, it can produce a new, lower energy balance level that is insufficient to operate the body’s functions in a healthy manner. In other words, you may experience a decrease in your metabolism. Available low energy levels can also compromise short- and long-term athletic performance.

What are my needs?

How can we calculate the available energy needed by the body? What is the actual caloric intake you need? Available energy refers to the vital functions of the body and is therefore not dependent on body fat. To calculate it, we will have to measure the proportion of fat and lean body mass in our body composition. To help you, you can purchase an impedance scale at home that will provide you with the answer.

An amount of available energy of 45 calories per kg of lean body mass per day is associated with a stable energy balance and optimal health for athletes. Therefore, this is the optimal target for the number of calories in your diet to improve performance. Thus, an individual who would have 40 kg (88 lb) of lean body mass should have 1800 calories in their daily diet available. And therefore, if the individual expends 400 calories, his total intake should be 2200 calories.

Harmful Calorie Restriction

With a reduction in caloric intake below 30 calories per kg of lean body mass per day health and performance problems can occur. To use the same example, a person who would have 40 kg (88 lb) of lean body mass with an intake of 1200 calories per day would be below the minimum requirement.

This can happen when not enough calories are consumed each day. When there is a high energy expenditure or a combination of both factors. For example, the same 40 kg of lean body mass person could have a caloric intake of 1800 calories per day. If he or she expends more than 600 calories during training then he or she will have an available energy ratio of 30 calories per kg of lean body mass.

Do you understand the difference? With the concept of energy balance, a person consuming 1800 calories per day would most likely be above their basal metabolic rate and therefore would be considered to be on an adequate diet. However, if that person is expending a significant amount of calories during training, that energy intake may not be sufficient.

Deficient available energy may be associated with eating disorders, but also with a rapid weight loss program. It can also occur in competition or training when it is more difficult to make up for lost calories.

Weight Loss

Thus, for people who are active on a daily basis, slow weight loss is the best option to improve not only their physical abilities but also their body composition. This helps to maintain lean mass and reduce excess fat.

Performance and lean body mass were better preserved for athletes who lost less than 1% of their weight per week (3). For a 70 kg (154 lb) person, this represents a weight loss of approximately 0.7 kg or 1.5 lb.

The important thing to remember from this article is that many factors are important in your daily life to improve your physical abilities, body composition and therefore performance. To lose weight, many people decrease their calorie intake and significantly increase the energy they expend. You should be careful when using calorie restriction for weight loss. It can affect your metabolism and health even if you do not fall below your basal metabolic rate.

If you are struggling and want to know how you should achieve these recommendations, you can request a food plan. This will provide a detailed calculation of your needs and how to achieve them.

Sandrine Lavoie-Filion, Sandrine Santé Active


Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine Joint Position Statement: nutrition and athletic performance. Med Sci Sports Exercise. 2016;48(3):543–68.

Delk-Licata A, Behrens CE, Benardot D, et al. The Association Between Dietary Protein Intake Frequency, Amount, and State of Energy Balance on Body Composition in a Women’s Collegiate Soccer Team. Int J Sports Exercise Med 2019