Calories are a measure of the energy released by food as it is digested by the human body.
The calorie intake needed per day depends on
If you are thin and underweight, then you need more calories than you burn daily. On the other hand if you are overweight or obese, then you need to intake less number of calories than you burn. People who consume more calories than they burn off in normal daily activity or during exercise are more likely to be overweight or obese.
Recommended daily calorie intake (in calorie)
Age (in yrs) 10 – 20 20 – 60
Male 2200 – 2800 2500 - 2700
Female 1800 – 2100 1850 - 2000
Caloric value of major nutrients
Fat: 1gram = 9 calories
Protein: 1gram = 4 calories
Carbohydrates: 1gram = 4 calories
Alcohol: 1gram = 7 calories
Carbohydrates are a major source of energy and should account for 50 percent to 60 percent of calories consumed each day.
Carbohydrates are found in whole grain cereals, flour, bread, rice, corn, oats, potatoes, and legumes.
Fat should account for 30 percent or less of the calories consumed daily, with saturated fats accounting for no more than 10 percent of the total fat intake. Excess calories from protein and carbohydrates are converted to and stored as fat. Even if you are eating mostly "fat free" foods, excess consumption will result in additional body fat. Fat calories in food are readily stored, while it takes energy to transform protein and carbohydrates to body fat. The only proven way to reduce body fat is to burn more calories than one consumes.
Protein should account for 10 percent to 20 percent of the calories consumed each day. Protein is essential to the structure of red blood cells, fo...