Prolonged caloric deficit and low calories

Reducing calories and maintaining very low caloric intake for an extended period can lead to a slowdown in metabolism and make weight loss difficult.

This happens because the body has adaptive mechanisms that aim to preserve energy in situations of food scarcity. When there is a prolonged caloric deficit, the body enters an alert state to conserve energy and minimize caloric expenditure.

There are several ways in which metabolism can be affected by a prolonged caloric deficit:

1. Decreased resting energy expenditure: Basal metabolism, which represents the number of calories the body burns at rest to maintain vital functions, tends to decrease when caloric intake is very low over an extended period. This occurs because the body perceives the lack of energy and reduces the pace of its activities to save calories.

2. Muscle loss: When the body does not receive enough calories to meet its daily needs, it may resort to breaking down muscle tissue for energy (catabolism). This occurs primarily in diets severely restricted in protein. Muscle loss is concerning because muscles are more metabolically active than fat, meaning that the body burns more calories to maintain them.

3. Reduction in the thermic effect of food (TEF): The process of digesting and absorbing food requires energy, contributing to the total caloric expenditure. With low caloric intake, the thermic effect of food decreases, resulting in fewer calories burned during digestion.

4. Hormonal response: The lack of calories can affect the hormonal regulation of appetite, increasing feelings of hunger and making it difficult to maintain a low-calorie diet in the long term.

5. Metabolic stress: Extremely restrictive diets can put the body in a state of metabolic stress, leading to increased cortisol levels (the stress hormone). Elevated cortisol levels can lead to abdominal fat accumulation and further hinder weight loss.

6. Modification of gut microbiota: An unbalanced and nutrient-poor diet can affect the composition of the gut microbiota, playing an important role in metabolism and body weight regulation.

7. Irritability and mood swings: Caloric deprivation can affect emotional state, making a person more irritable and emotionally unstable.

8. Hormonal issues: A diet with a prolonged caloric deficit can interfere with the body's hormonal balance. This can affect the menstrual cycle in women and lead to hormonal imbalances in both sexes.

9. Decreased immunity: Inadequate nutrition weakens the immune system, making the body more susceptible to infections and illnesses.

10. Difficulty concentrating: The lack of calories can impair brain function and the ability to concentrate and focus.

11. Fatigue and lack of energy: With such low caloric intake, the body may not obtain enough energy to perform daily activities adequately. This can lead to a constant feeling of tiredness and fatigue.

In summary, the practice of extremely low-calorie diets for an extended period can result in a series of metabolic adaptations that make weight loss difficult. It is important to remember that healthy and sustainable weight loss requires a balanced approach, with a nutritionally adequate diet and regular physical activity.