The definition of a calorie is the amount of energy needed to raise the temperature of 1 kilogram of water 1 °C. When applied to human nutrition, one calorie (aka kilocalorie) is equal to one thousand “small calories” used to measure the energy value of foods.
Long story short, calories=energy. Of course, even this oversimplification is vague and potentially confusing, so most of us grow up with an understanding that we need calories but not too many and that something about the number 2000 is important so try not to go over that. Somehow.
Some foods are high in calories, and some foods are low in calories. How quickly you work your way up to your particular calorie limit each day (if you know what it is at all) depends on the caloric content of the foods you eat. It’s hardly news that restaurant and chain portion sizes are huge and provide excess calories, but sometimes reading about it doesn’t give that clear a picture. That’s why visual comparisons can be helpful when deciding how to “spend” those calories.
This article provides a great visual comparing what 2,000 calories looks like at various chains compared to what you can prepare at home for the same amount.
Do you pay attention to calories?