Counting calories is a way to control the amount of food you consume daily. If you want to lose weight, gain muscle mass, or maintain your current weight, it is important to know how many calories you are consuming.

Total Energy Expenditure (TEE) is the total amount of energy the body uses throughout the day to perform all its functions, including maintaining vital activities (such as breathing and heartbeat) and physical activities. It is composed of basal metabolism, which represents the energy needed to maintain essential body functions, the thermic effect of food, which is the energy used in digestion, and physical activity. TEE is important to help understand the balance between calorie intake and expenditure, being an essential indicator for planning diets, weight loss or gain programs, and improving physical performance.

Basal Metabolic Rate (BMR) is the minimum amount of energy the body needs to maintain its vital functions at rest, such as breathing, blood circulation, body temperature regulation, and organ function. It represents the fundamental caloric expenditure for the body while in total inactivity. BMR can be influenced by various factors such as age, sex, weight, height, body composition, and genetics. To calculate BMR, specific formulas can be used, the most common being the Harris-Benedict equation, which considers sex and physical characteristics.
The formula for men is:
BMR = 88.36 + (13.4 × weight in kg) + (4.8 × height in cm) - (5.7 × age in years)

For women:
BMR = 447.6 + (9.2 × weight in kg) + (3.1 × height in cm) - (4.3 × age in years)

Calories are units of energy measurement that food provides to the body, essential for the functioning of all its vital functions, such as breathing, moving, and maintaining body temperature. The amount of calories a person needs depends on factors such as age, sex, level of physical activity, and health goals. Macronutrients are the nutrients that provide these calories and are divided into three categories: carbohydrates, proteins, and fats. Carbohydrates are the main source of energy for the body, providing 4 calories per gram, while proteins are essential for building and repairing tissues and also provide 4 calories per gram. Fats, which provide 9 calories per gram, are important for vitamin absorption and organ protection. The proper distribution of these macronutrients in the diet is essential to maintain energy balance and overall health.

Body Mass Index (BMI) is a measure used to assess whether a person has an adequate weight in relation to their height. It is calculated by dividing weight (in kilograms) by height (in meters) squared. BMI is classified into different ranges, such as underweight, normal weight, overweight, and obesity, helping to identify health risks related to excess or lack of weight. Although BMI is a useful tool for initial nutritional assessment, it does not take into account body composition, such as the proportion of muscle mass and fat, and may not be suitable for athletes or people with high muscle mass. Even so, it is widely used by health professionals to monitor and guide eating habits and physical activities.

Water intake is essential to maintain the body's water balance and ensure the proper functioning of various vital functions, such as temperature regulation, nutrient transport, toxin elimination, and joint lubrication. The ideal amount of water varies according to individual factors such as age, weight, level of physical activity, climate, and health conditions. A general recommendation is to consume about 2 to 3 liters of water per day for adults, but this need may increase in cases of intense physical activity or hot weather. Additionally, it is important to remember that fluid intake can also come from food and other beverages, such as soups, fruits, and teas. Staying hydrated is crucial to prevent dehydration, which can cause fatigue, difficulty concentrating, and other health problems.