Every food has a caloric value. This value quantifies the energy that a specific food will provide you.

Caloric values should be taken with caution and viewed as reference points rather than absolute measures. In practice, the energy value of food is determined using a calorimeter, where we measure the heat released by combustion. Naturally, a piece of bread does not burn in the human body, energy is derived from breaking down the molecules of fuel, which generates energy.

Energy is measured in calories, more precisely in kilo-calories (kcal) or kilojoules (kJ). Both units are commonly used, and it is true that 1 kcal = 4.184 kJ. For simplicity, if you see the value in calories on the packaging and multiply it by 4, you will obtain the energy in kilojoules.

Each food contains 3 macronutrients:

• fats: 1g of fat has 9 kcal
• carbohydrates (starches and sugars): 1g of carbohydrates has 4 kcal
• proteins: 1g of protein has 4 kcal

The human body has certain energy needs to maintain basic functions. We refer to this energy as basal metabolism. There are various formulas for calculating it, but this is not an exact science either. You can calculate your basal metabolism, for example here. This will provide you with information about how much energy you need per day when you are at rest.

Then multiply the data obtained in this manner by the coefficient that reflects your level of physical activity:

• x 1.2 = sedentary lifestyle (minimal or no physical activity)
• x 1.375 = light activity (exercise 1-3 times a week)
• x 1.55 = moderate activity (exercise 3-5 times a week)
• x 1.725 = high activity (intensive exercise 6-7 times a week)
• x 1.9 = very high activity (physically demanding work or training twice a day)

This will give you the amount of energy you actually consume per day.

Logically, if you consume less energy daily, you should begin to lose weight, if you consume more, you should gain weight; and if you consume the same amount, your weight should remain stable.

Let's consider a man, aged 50, weighing 74 kg and standing 183 cm tall, who is moderately physically active. This man has a basal energy expenditure of 1639 kcal per day. Moderate activity corresponds to x1.55, so the daily energy intake for weight maintenance should be 2540.45 kcal. If this man aims to lose weight, he can set a goal for his daily caloric intake not to exceed 2100 kcal. There is little benefit in drastically reducing calories, as such a plan is harder to maintain and can also shock the body. Therefore, 2100 to 2200 kcal is the ideal daily intake for this man to gradually start losing some pounds.

>>>