Daily calorie intake is the amount of energy the body needs to function and maintain metabolism. Reducing the calorie intake by 10-15% per day leads to weight loss, while in order to gain muscle mass, you need to increase the calorie content of the daily diet.
You can calculate the calorie intake either using the Harris-Benedict formula or determine the average figure using the tables – they are presented below. However, the formula does not take into account the fact that a person’s calorie needs always vary.
Daily calorie norms
The daily calorie intake depends not only on the gender, age, and weight of a person but also on the level of physical activity and the number of steps taken on a particular day. In addition, the goal of losing weight, maintaining existing weight, or gaining muscle also affects the calculation of the calorie norm.
The average calorie intake per day (for people aged 17-60 years, with a standard build and with an average level of physical activity) is 2400-2800 kilocalories for men and 1800-2200 kilocalories for women. The daily requirements of children and adolescents are below.
For a more accurate calculation, you can use the formulas presented in the material (primarily the Harris-Benedict formula), tables, or an online calculator. However, we note that it is possible to calculate the figure only with an error of 200-300 kcal per day.
Is calorie calculation the basis of a diet?
It is important to understand that the norm of calories is a conditional figure. Both the calculation method itself and the numbers indicated in the calorie tables may vary. It also plays a role that the absorption of nutrients from food is rarely 100%, and energy requirements on a given day may be higher or lower.
The daily calorie intake is only a general guideline for compiling a diet, while in practice it is more convenient to calculate the consumption rates of macronutrients (proteins, fats, and carbohydrates). It’s also important to consider the glycemic index of carbohydrates—how quickly they raise blood sugar levels.
Daily Energy Rates – tables
If you are a woman, you are 30 years old, you work in an office, and exercise regularly, then your calorie intake will be from 1800 kcal to 2200 kcal. A more accurate formula calculation figure will only be a random choice that does not guarantee additional accuracy.
Among other things, the level of assimilation of vegetable proteins does not exceed 50-70%, and the fiber contained in the products is not absorbed at all (although it is included in the “carbohydrates” column) – that is, the nutritional value indicated on the package is considered purely mathematical.
Calorie table for women
| Age | Activity level | Calorie norm |
| 17 – 40 years old | Low | 1800 – 2000 kcal |
| Medium | 2000 – 2200 kcal | |
| High | 2200 – 2400 kcal | |
| 41 – 60 years old | Low | 1600 – 1800 kcal |
| Medium | 1800 – 2000 kcal | |
| High | 2000 – 2200 kcal | |
| Over 61 | Low | 1600 kcal |
| Medium | 1800 kcal | |
| High | 2000 kcal |
After reaching the age of 40, the metabolic rate in women usually decreases. A decrease in estrogen levels after menopause leads to a change in the body’s susceptibility to carbohydrates – and associated weight gain. On average, women gain from 5 to 7 kg.
Calorie table for men
| Age | Activity level | Calorie norm |
| 17 – 40 years old | Low | 2400-2600 kcal |
| Medium | 2600-2800 kcal | |
| High | 3000-3200 kcal | |
| 41 – 60 years old | Low | 2000-2200 kcal |
| Medium | 2400-2600 kcal | |
| High | 2600-2800 kcal | |
| Over 61 | Low | 2000 kcal |
| Medium | 2200-2400 kcal | |
| High | 2400-2600 kcal |
Male metabolism is characterized by testosterone levels, a hormone that helps maintain muscle mass and burn fat. However, after 30-35 years, testosterone begins to fall – against the backdrop of a sedentary lifestyle and malnutrition, this leads to an increase in belly fat.
Calorie table for children and teenagers
| Age | Activity level | Calorie norm |
| 14 years | Low | 1000 kcal |
| Medium | 1200-1400 kcal | |
| High | 1400-1600 kcal | |
| 5 – 8 years | Low | 1200-1400 kcal |
| Medium | 1400-1600 kcal | |
| High | 1600-1900 kcal | |
| 9 – 11 years | Low | 1500-1800 kcal |
| Medium | 1800-2000 kcal | |
| High | 1900-2200 kcal | |
| 12 – 16 years | Low | 1600-1800 kcal |
| Medium | 2000-2500 kcal | |
| High | 2500-3000 kcal |
The reason for the growth of the abdomen in teenagers is the love of sweets and snacks. Feeding children fast carbohydrates (sugar, honey, cornflakes, sweets, chocolate) provokes negative hormonal changes, including those associated with brain function.
Required calorie rate calculation formula
Calculating your daily calorie intake starts with determining your basal metabolic rate (BMR), which is the energy your body needs to stay alive. The figure includes the calorie requirements for brain function, maintaining body temperature, digestion of food, and metabolic processes.
At the same time, BMR does not take into account physical activity – and from 20 to 90% of daily calories are spent by the body not on metabolism, but on daily movement. Depending on the level of loads, an additional coefficient of human activity is selected (from 1.2 to 1.9), by which the BMR figure is multiplied.
The Harris-Benedict formula
The first version of the formula for calculating the norm of calories was presented in 1919 by anthropologists James Arthur Harris and Francis Gano Benedict. To compile the formula, they examined 239 subjects of different sexes and ages with different percentages of body fat. The formula was revised and refined in 1984.
The formula for calculating the base calorie intake:
- for men: BMR = 88.36 + (13.4 x weight, kg) + (4.8 x height, cm) – (5.7 x age, years)
- for women : BMR = 447.6 + (9.2 x weight, kg) + (3.1 x height, cm) – (4.3 x age, years)
To determine your daily calorie requirement, multiply the BMR corresponding to your gender, age, and weight by your activity factor. In turn, this coefficient is determined depending on the level of physical activity on a particular day.
Daily activity ratio
The Harris-Benedict formula for calculating daily calorie intake defines five types of physical activity. Minimal (no exercise), Low (exercise 1-3 times a week), Medium (3-5 days a week), High (6-7 times), and Very High (exercise more than once a day).
However, it is in the activity coefficient that the key problem of any calorie calculation formula lies. After accurately calculating BMR (for example, 1765 kcal), you need to multiply the figure by your activity factor, which varies from 1.2 to 1.9. The final result will be from 2118 kcal to 3354 kcal – a difference of 1236 kcal.
Activity coefficients when calculating the calorie norm:
- Minimum activity level – 1.2
- Low activity level – 1.375
- Medium activity level – 1.55
- High level – 1.725
- Very high – 1.9
Calculating the calorie norm using gadgets
Trying to calculate the daily calorie intake using gadgets, and entering your height, age, and weight into a fitness bracelet, you will only get an approximate figure. Although the Harris-Benedict formula will be used as a basis, it is difficult to say which activity factor will be used in the calculation.
“Smart scales” also determine the norm of calories very conditionally – most often, solely on the basis of body weight. Such devices are very approximate for measuring the percentage of fat in the body – often using a plastic caliper is easier. A reliable figure can be obtained only on professional equipment.
Note that the calculation of the calorie rate is only suitable for people of average build. For overly thin, overweight, or even muscular people, the Harris-Benedict formula cannot be applied, because with a high body mass index, ballast fat weight does not require energy.
The formula for calculating the daily calorie intake determines the body’s basic need for energy without taking into account physical activity. To determine the total calorie requirement, you need to know the coefficient, which cannot be accurately determined. That is why any methods for calculating the norm of calories per day have an error of 200-300 kcal.
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