Calories can be a scary term. How many should a person consume a day to lose weight or to maintain a healthy weight? The answer is not a pleasing one: It depends. It gets even more complicated because one size does not fit all,  and the answer depends on many factors, including age and size, as well as specific foods and their ingredients.

But there are ways to estimate with a fairly small margin of error. 24/7 Tempo compiled a list of some of the people’s favorite foods and the time it takes to burn off the calories in them. We used data from Nutritionix, a global nutrition database offering information on food, health, fitness, restaurants and food manufacturers, with values based on a person weighing 140 lbs. Heavier people may burn off calories in less time because it takes them more energy to perform a certain activity.

Many people have some history with calorie counting. Calories — depending on whether they come from carbs, fat, or protein — are sometimes seen as the enemy. But that is a simplistic view. These are 17 things nutritionists want you to know about calories.

A 2013 study published in the British Medical Journal showed that people were consuming more calories than they thought. At least two thirds of the 1,800 participants underestimated the calorie content of their meals, some by a significant amount. One reason might be that people simply did not look at the ingredients label; another that they did not notice the serving size.

Knowing how many calories a person is consuming is key to preventing weight gain and the negative health outcomes that come with it. But exercising and burning off energy is also crucial to maintaining a healthy weight or losing a few extra pounds.

Click here to see how much time it takes to burn off the calories from your favorite foods