Calories are units of energy and is measures such that 1 calorie is enough to raise 1 kilogram of water by 1 degree Celsius. In English, calories measure the amount of energy you consume in your diet and the amount you burn during regular day-to-day activities. 

In general, a sedentary woman can burn between 1,800 to 2,000 calories per day. The amount burned varies according to age, weight, and height and does not include any physical activity such as walking, house chores, or activities done at work.  

There are three types of food energy sources: 
• Fats: 9 kcals 
• Carbohydrates: 4 kcals 
• Proteins: 4 kcals 

So, what happens to the calories you do NOT burn? Well, take carbohydrates for example, if you eat a diet high in carbohydrates and you do not burn all of it, the remainder ends up storing in your body as triglycerides (another name for fat). In the same sense, the more fat you eat and don't burn ends up storing in your body as fat as well. 

As mentioned in the "Proteins" article, proteins release acid which is neutralized by calcium. The remainder simply becomes a waste product. 

The guidelines for dietary intake in the U.S. states that an individual should consume no more than 2,000 calories per day. Those who eat more and are not physically active tend to gain weight or have a risk of becoming overweight and even obese. This is because they are consuming more calories than they are burning. 

The goal for women's weight loss is to consume no less than 1,200 calories and to burn more calories than is consumed daily, or to burn as many calories as eaten to maintain the weight.