Calories come from all foods and drinks, except from water.
There is no such thing as "common foods". Foods are specific sometimes ot certain regions or areas, and there are so many foods out there. Please be more specific in your question, so WikiAnswers can provide you with the best possible answer.
Yes. There is no difference between the calories in fruit and in other foods. Most calories in fruits come from Sugars.
All foods have calories.
About 400 calories would be a good meal. Those 400 or so calories should come from healthy foods and drinks, too.
foods free of calories
Yes, calories from different foods are metabolized differently. The source of the calories will effect how they are metabolized.
all foods have calories in, some just have more than others!
There is a few foods that equals to 3,500 calories. You can get foods that are fresh like veggies and fruits.
calories.
It depends on what the calories are from. Some calories are from foods rich in proteins, while other are foods that have little to no protein in them at all.
Yes, it does. The total amount of calories must include all sources of calories in order to be accurate. Calories come from Fats, Carbohydrates, and Sugars. (Calories also come from alcohol, but that is usually irrelevant because most packaged foods do not contain alcohol.)
Yes. In the human body, when 3,500 calories go unused for 3 days, they are converted into fat molecules to be stored for future energy use. Calories also come from foods and drinks that we consume. Some of those foods are fats (molecularly, they are known as lipids due to their structure).