Daily calorie intake is the amount of energy the body needs to function and maintain metabolism. Reducing calorie intake by 10-15% per day leads to weight loss, while to gain muscle mass you need to increase the caloric 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, ultimately, the formula calculation does not take into account that a person’s caloric needs always vary.
Calorie intake per day
The daily calorie intake depends not only on a person’s gender, age, and weight but also on the level of physical activity and the number of steps taken on a particular day. In addition, the calculation of calorie intake is also influenced by the goal – losing weight, maintaining existing weight, or gaining muscle.
The average calorie intake per day (for people aged 17-60 years, with a standard build and an average level of physical activity) is 2400-2800 kilocalories for men and 1800-2200 kilocalories for women. The daily needs of children and adolescents are lower.
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 the figure can only be calculated with an error of 200-300 kcal per day.
Average calorie intake:
- 2400-2800 kcal for men
- 1800-2200 kcal for women
Is calorie counting the basis of a diet?
It is important to understand that calorie intake is a relative figure. Both the calculation method itself and the figures indicated in the calorie tables may vary. It also plays a role that the absorption of nutrients from food is rarely 100%, and energy needs on a given day may be higher or lower.
The daily calorie intake is only a general guideline for creating a diet, while in practice it is more convenient to calculate the consumption rates of BZHU (proteins, fats, and carbohydrates). It’s also important to consider the glycemic index of carbohydrates—how quickly they raise your blood sugar.
Daily energy norms – tables
Accordingly, if you are a woman, you are 30 years old, you work in an office, and regularly play sports, then your calorie intake will be from 1800 kcal to 2200 kcal. A more accurate figure for calculations using the formula will only be a random choice that does not guarantee additional accuracy.
Among other things, the level of absorption of plant 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 packaging is considered exclusively mathematical.
Calorie norm table for women
| Age | Activity level | Calorie norm |
| 14 – 40 | Short Average High | 1800-2000 kcal 2000-2200 kcal 2200-2400 kcal |
| 41-60 | Short Average High | 1600-1800 kcal 1800-2000 kcal 2000-2200 kcal |
| Over 61 | Short Average High | 1600 kcal 1800 kcal 2000 kcal |
After reaching the age of 40, women’s metabolic rate usually decreases. Against this background, a decrease in estrogen levels after menopause leads to a change in the body’s sensitivity to carbohydrates – and the associated excess weight gain. On average, women gain from 5 to 7 kg.
Calorie norm table for men
| Age | Activity Level | Calorie norm |
| 17 – 40 | Short Average High | 2400-2600 kcal 2600-2800 kcal 3000-3200 kcal |
| 41 – 60 | Short Average High | 2000-2200 kcal 2400-2600 kcal 2600-2800 kcal |
| Over 61 | Short Average High | 2000 kcal 2200-2400 kcal 2400-2600 kcal |
Male metabolism is characterized by testosterone levels – this hormone helps maintain muscle mass and burn fat. However, after 30-35 years, testosterone begins to fall – against the background of a sedentary lifestyle and poor nutrition, this leads to the growth of belly fat.
Calorie norm table for children and adolescents
| Age | Activity level | Calorie norm |
| 4 | Short Average High | 1000 kcal 1200 – 1400 kcal 1400-1600 kcal |
| 5 – 8 | Short Average High | 1200-1400 kcal 1400-1600 kcal 1600-1900 kcal |
| 9 – 11 | Short Average High | 1500-1800 kcal 1800-2000 kcal 1900-2200 kcal |
| 12 – 16 | Short Average High | 1600-1800 kcal 2000-2500 kcal 2500-3000 kcal |
The reason for the growth of the belly in teenagers is the love of sweets and snacks. Children eating fast carbohydrates (sugar, honey, cornflakes, candies, chocolate) provokes negative hormonal changes, including those related to brain function.
Calculation of calorie intake – formula
Calculating your daily calorie intake begins with determining your basal metabolic rate (BMR)—the energy your body needs to function. The figure includes calorie needs for brain function, maintaining body temperature, digesting food, and metabolic processes.
However, 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 everyday movement. Depending on the level of load, an additional human activity coefficient is selected (from 1.2 to 1.9), by which the BMR figure is multiplied.
Harris-Benedict formula
The first version of the formula for calculating calorie intake was presented in 1919 by anthropologists James Arthur Harris and Francis Gano Benedict. To compile the formula, they studied 239 subjects of different genders and ages with different percentages of body fat. The formula was revised and refined in 1984.
Formula for calculating the basic 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)
Accordingly, to determine the body’s daily caloric needs, you need to multiply the BMR corresponding to your gender, age, and weight by the activity factor. In turn, this coefficient is determined depending on the level of physical activity on a particular day.
Daily activity rate
The Harris-Benedict formula for calculating daily calories defines five types of physical activity. Minimum level (no exercise), low level (physical activity 1-3 times a week), medium level (3-5 days a week), high level (6-7 times), and very high level (exercise more than once a week). day).
However, it is in the activity coefficient that the key problem with any calorie calculation formula lies. Once your BMR is accurately calculated (eg 1765 kcal), you need to multiply the figure by your activity factor, which ranges 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 calorie intake:
- Minimum activity level – 1.2
- Low activity level – 1.375
- Average activity level – 1.55
- High level – 1.725
- Very high – 1.9
How to calculate your daily calorie intake?
Here are some examples of calculating daily calorie intake using the Harrison-Benedict formula:
- Male, 25 years old, height 178 centimeters, weight 72 kilograms, plays sports three times a week, the rest of the days he works in the office:
BMR = 88.36 + (13.4 x 72) + (4.8 x 178) – (5.7 x 25) = 1765 kcal
Calorie Value = BMR x Activity Level = 1765 x 1.55 = 2735 kcal
- Woman, 25 years old, height 172 centimeters, weight 50 kilograms, goes in for fitness four times a week, leads an active lifestyle, being on the move most of the day:
BMR = 447.6 + (9.2 x 50) + (3.1 x 172) – (4.3 x 25) = 1333
Calorie Value = BMR x Activity Level = 1333 x 1.725 = 2299 kcal
Calorie intake norm – calculation using gadgets
Trying to calculate your daily calorie intake using gadgets and entering your height, age, and weight into a fitness bracelet, you will only get an approximate figure. Even if the Harris-Benedict formula will be used as a basis, it is difficult to say which activity coefficient will be used in the calculation.
“Smart scales” also determine the calorie intake very conditionally – most often, solely based on body weight. Such devices are also very approximate for measuring the percentage of body fat – often using a plastic caliper is easier. A reliable figure can only be obtained using professional equipment.
We also note that calculating calorie intake is only suitable for people of average build. For excessively thin, overweight, or even muscular people, the Harris-Benedict formula cannot be used, since with a high body mass index, ballast fat weight does not require energy.
Conclusion
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, it is necessary to know a coefficient that cannot be determined accurately. That is why any methods for calculating calorie intake per day have an error of 200-300 kcal.