Calculate calories - you have to evaluate the daily requirement of calories the body with utmost precision, unfortunately, is impossible. Even the best calorie calculator can be wrong. The reason is simple - all people are unique and impossible to put them in a certain framework and formula. 
  
Note that a calorie calculator that focuses on those who are not dieting has a few formulas for calculating calories. You can choose any of them: the formula Mifflin San Zheora, the Harris-Benedict, but in the latter case, you need to know your percentage of fat tissue from total body weight. Also, you can calculate your calories based on the basic metabolic rate (BMR), on which takes into account the amount of energy that you actively spend the day. 
  

Formula Mifflin - San Zheora very "young", she bred in 2005, according to the American Dietetic Association (ADA), is today considered the most accurate counting calories for a healthy person. 
  
Men: 
10 x weight (in kilograms) + 6.25 x height (in cm) - 5 x age (in years) + 5 
  
Women: 
10 x weight (in kilograms) + 6.25 x height (in cm) - 5 x age (years) - 161 
  
Harris-Benedict formula 
Harris-Benedict formula was derived in 1919, and is characterized by large errors in the application of modern people with their way of life. As a rule, the calculation of calories according to this formula gives an increase of about 5%, consider this. 
  
Men: 
66.5 + (13.75 X weight in kg) + (5.003 X height in cm) - (6.775 X age in years) 
  
Women: 
655.1 + (9.563 X weight in kg) + (1.85 X height in cm) - (4.676 X age in years) 
  
Calculate calories - After the calculation of basic metabolic rate, the calculator takes into account the activity level of your lifestyle. Depending on the level of activity, BMR is multiplied by a factor ranging from 1,2 to 1,9. So, you know the number of necessary, so to speak, serving calories. To find the standards that are at the same fat loss, you must subtract from the sum was 20%. For very obese people - 40%. But remember that there is a lower limit; it is assumed that it is equal to 8 calories per 450 g of body weight.

If the calories obtained by a person with meals is less than it consumes them, then people lose weight. If the same number of calories consumed from food exceeds energy expenditure, the unused calories are deposited on the body as fat.