Nutritional substances include three sources of energy such as proteins, fats and carbs. Entering human body, they are burned like a gasoline to provide organism with life power, energy and ability to live and breathe. Energy is measured in calories. Optimal amount of calories ensures right body type, correct muscle gain and overall wellbeing. Excess of energy, which is not used by body, is transformed into fat deposits. This results in pale skin, anemia, weight loss and indifferent attitude towards life. Conclusion: it is necessary to know how many calories you should consume per day to stay fit and ensure proper course of physiological processes in your body.
Here, we will familiarize you with main terms which define metabolism extent in both sexes, sportsmen, men and women of different age categories.
Calculation of Estimated Energy Requirement
Daily caloric intake is calculated in accordance with Desirable Estimated Energy Requirement (DEER) which is affected by the following factors:
- Basal metabolic rate or BMR is the lowest limit of nutritional value of the food, which ensures vital functioning of the human body in resting state. Energy consumption at BMR comprises 1 kcal per hour per one kilo of weight. It is not acceptable for healthy body 24 hours per day. BMR requirement should only work for the patient in coma state.
- Base factors are also complemented with non-exercise associated thermogenesis. This factor includes daily activity at home, shopping, laundry doings and house cleaning.
- International classification also notes the process called Thermogenic effect of feeding or TEF. This process signifies certain amount of calories spent to digest consumed food. This factor depends on the food content as protein and rough fibers require a greater TEF. Consumption of fats lowers amount of calories involved into metabolic processes. Attention: This factor does not depend on food consumption frequency: you can consume 1800 kcal, which is daily caloric intake, at once or consuming food 6 times per day. Caloric consumption will be the same.
- Exercise associated thermogenesis or EAT plays an important role, as well. If you are doing simple exercises in elliptical machine couple times per week, then you shouldn’t care about EAT. It only works during regular 2-hour workouts.
Thus, total and optimal daily caloric intake is defined by adding up all the four factors mentioned above as follows:
BMR + EAT + NEAT + TEF
These terms will be useful to calculate qualitative factors per common formulas accepted by nutritionists.
Nutritionists advise on daily caloric intake without going into mathematical calculations. Men, who are engaged into physical labor, were always instructed to consume from 2500 up to 2700 kcal. Women were recommended to consume from 2200 up to 2000 kcal per day. Metabolic rate, individual characteristics such as height and body type were not taken into consideration. Only American nutritionists were the first to fully consider gender and age differences as well as overall activity levels.
BMR was calculated per equation proposed by James Arthur Harris and Francis Benedict. Today it is considered a classic and outdated one as BMR has been calculated considering height and weight, but not the levels of physical and intellectual activity. After seven decades, the formula has been refined. Today, it looks like this:
- For males, BMR = 88.362 + (13.397 multiplied by weight in kilos) + (4.799 multiplied by height in centimeters) — (5.677 of age in years).
- For females, BMR = 447.593 + (9.247 x weight) + (3.098 x height) — (4.330 x age in years)
Nowadays, the following formula, which was calculated by American nutritionists led by Dr. San Zheora and Dr. Mifflin, has become increasingly popular. Equation has been named in honor of the leaders of the project completed in 2005 and it can be used for certain individual. The formula is used in modified and simplified forms.
«Simple» equation of Mifflin and San Zheora includes common parameters to conduct calculation for men and women:
- Weight in kilograms is multiplied by 10.
- Height in centimeters is multiplied by 6,25.
- Fivefold age in years is deducted from sum of these two factors.
Then, 5 units is added to result in formula for men and 161 units is deducted from result in formula for women. Simple calculation of daily caloric intake does not consider extent of physical activity. Scientists suggested to use more accurate option, where they used coefficient of physical activity (А) of five degrees:
- minimum A stands for coefficient of 1,2;
- weak A stands for coefficient of 1,375;
- medium A stands for coefficient of 1,55;
- high A stands for coefficient of 1,725;
- extra A stands for coefficient of 1,9.
The highest activity coefficient is used with sportsmen, who are professionally involved into strength training (two workouts per day) as well as with those people, who daily do heavy physical work.
To accurately calculate daily caloric intake, results, which are obtained using «simple» formula, are multiplied by value of one of five coefficients.
The World Health Organization has also developed a formula taking into consideration physical activity level. It identified three levels of physical activity. The activity coefficients (CFA) are defined as follows:
- CFA 1 stands for low activity level;
- СFA 1, 3 stands for medium activity level;
- CFA 1,5 stands for high activity level.
Calculation of daily caloric intake for men and women is done according to age categories:
- 18-30 years old: for women (0,062 × weight in kilos + 2,036) × 240×CFA and for men (0,063 × weight in kilos + 2,896) × 240 × CFA.
- 31-60 years old: normal value for women = (0,034 × weight in kilos + 3,538) × 240×CFA; normal value for men: (0,484 × weight in kilos + 3,653) × 240 × CFA.
- Over 60 years old: normal value for women: (0,038 × weight in kilos + 2,755) × 240; normal value for men: (0,491 × weight in kilos + 2,459) × 240. All obtained results are multiplied by activity coefficient.
Let’s consider an example:
28 years old woman with medium level of physical activity weighs 53 kg. Her daily caloric intake should not exceed 1660 kcal.
There is also another formula, which is used to determine MBR and considers the amount of body fat. It is the Ketch – McArdle equation. It could be considered an ideal one if it would consider a height, age and sex of a certain person in question. A person, who does not know the ratio of body fat to body weight, will not be able to take advantage of this equation.
Calculation of daily energy requirement can be done using these formulas as well as online calculator.
Daily Caloric Intake for Sportsmen
Calculation of daily energy requirement is important for those, who train intensively and are aiming at achieving the best results in sport. The goal of an athlete is to gain muscle. And his task is to get rid of the body fat. We calculate a normal value by multiplying the weight by a factor of 33 in case of a presence of a “fast metabolism”. And in case of “slow” metabolic rate, factor of 29 acts as a multiplier. Having an average metabolism, one should use a factor of 31. The calculations are provided to maintain corresponding weight and muscle mass growth.
If you want to get rid of extra kilos, then use «lowering» coefficients from 22 up to 26. Nutritionists and sports coaches recommend to keep the food diary once individual caloric intake has been established. One should mark his weight, consumed calories and overall feelings in such a diary. Remember that even 100 kcal affect weight and muscle gain.
Next step towards healthy nutrition is calculation of nutrients. Bodybuilders get up to 40% of energy from proteins. Each gram of protein provides body with 4 kcal when being broken down. Fats provide body with 9 kcal. So, menu should include 10-15% of fats. The rest of energy should be obtained from carbs. Highly caloric food should be consumed after competitions or workouts.
Recommendations: when losing weight, you should consume the foods with «negative nutritional value» such as fresh cabbage, celery and ginger. Digestion of veggies takes more energy than they provide body with.
Mathematical calculations done to find out daily caloric intake are good for you as you begin to eat the “right” foods avoiding fast foods and simple carbohydrates. Calculating energy value of certain foods, you might experience difficulties at first, but then you will enjoy by benefits and energy healthy food will provide you with. Adjusting eating habits during physically active days will enable you to treat yourself with a cake, chocolate or sweet fruit without a fear of gaining weight. When you are enjoying the days during of which you don’t build your body, it is advisable to reduce foods consumption rate by 5-10%.
Armed with a correct formula and adjustment factors, you will obtain good habits and stay fit.