So, any food we eat consists of proteins, fats and carbohydrates. Proteins are used mostly for construction of cells and tissues; fats and carbohydrates are burned in our organism and give it out their energy.
We need this energy because we use it every moment of our life: to keep the body temperature at the level of 36.6 ºC, for each heart beat, for each breath. Our organism spends energy on every movement, conversation, food digestion and performance of vital functions. And the fact that a person gains weight is explained by thermodynamics laws. The idea is that if our organism spends less energy than it receives all unused calories turn into energy supply (fat deposits that are supposed to be used in situations when our organism receives not enough nutrients).
And on the contrary, if our organism spends more energy than it receives we start to lose weight. That’s why stout people who want to lose weight are always advised to do sports and reduce their food calorie content.
So, what are nutrition calories?
Each food product has its energy value expressed in nutrition calories. The most energy-rich substances are fats: when consuming 1gr of fat our organism receives 9.3 calories while it receives only 4.1 calories from the same amount of proteins or carbohydrates.
If we assume that a person’s daily energy needs amount 3000 kilocalories but he consumes only 2500 kilocalories his organism will use fat supply to get additional 500 kilocalories. And on the contrary, if we receive more energy than our organism requires (for example, 3500 kilocalories instead of 2500) it will stock the rest energy (1000 in our example) as fat in our thighs, belly and other ‘problem’ body parts.
Nutrition Calorie necessity
Individual nutrition calorie necessity is determined by metabolism rate and physical activity. When defining it, we should also take into consideration the level of sports preparedness, age and sex. For example, a younger and more muscular person will require more kilocalories than untrained and less young one.
Food for us is not just a means to suppress our hunger but is also the source of vital energy necessary for any kind of activity. So, the amount of required calories is calculated in accordance with our activity, metabolism rate and physical loads.
Daily calorie necessity = basic metabolism X physical loads
The necessary daily calorie content is determined by basic metabolism and by the energy we use throughout a day. To calculate its amount you need to multiply your basic metabolism by physical load factor.
Basic metabolism (resting metabolism) is the very quantity of energy used by a person or animal when resting on an empty stomach and at maximum comfort temperature (18-20 ºC for humans).
Control factors for middle calorie consumption
|Women / men||1.2|
|Age: 15 to 19 years||1460||2000||2300||2600||2900|
|Age: 19 to 25 years||1390||1900||2200||2500||2800|
|Age: 25 to 51 years||1340||1900||2100||2400||2700|
|Age: 51 to 65 years||1270||1800||2000||2300||2500|
|Age: after 65 years||1170||1600||1800||2100||2300|
|Age: 15 to 19 years||1820||2500||2900||3300||3600|
|Age: 19 to 25 years||1820||2500||2900||3300||3600|
|Age: 25 to 51 years||1740||2400||2800||3100||3500|
|Age: 51 to 65 years||1580||2200||2500||2800||3200|
|Age: after 65 years||1410||2000||2300||2500||2800|
Physical load coefficient
1.2: old weakened people: exclusively fixed mode of life;
1.4-1.5: officials, fine mechanics specialists, etc.: sedentary work, relaxed or low-activity leisure-time;
1.6-1.7: laboratory assistants, drivers, students, conveyer workers: sedentary work;
1.8-1.9: housewives, salespersons, waiters, mechanical engineers: a lot of walking or standing work;
20.0-2.4: builders, farmers, people performing timber works, miners, professional sportsmen, etc.: hard physical work.
This table shows us that daily calorie necessity is defined by metabolism multiplied by physical load factor. You can easily calculate your necessary daily calorie quantity according to the following formula:
1 kilocalorie/kg X nominal weight (in kilograms) X 24 hours
The basis of this formula (the first term) is the index of average basic metabolism that amounts 1 kilocalorie or 4.184 kilojoules per 1 kilogram of weight.
Example: 1 kilocalorie/kg X 70kg X 24h = 1680 kilocalories
You can find out more exact figures of your energy expenditure if you use the energy expenditure table placed in the appendix.