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Written by: Anne Hogan and Kristen DiFilippo, PhD, RDN

Sometime today, pick up a food package and look at the Nutrition Facts. Most likely, the biggest number you’ll see is the number of calories. This is intentional – the number of calories is big so consumers can easily see this information (FDA, 2022). Understanding what calories are and how they apply to your personal needs is an important step in building a healthy diet.

So, what are calories?

Simply put, a calorie is a measure of energy. In food, calories make up the total energy our bodies can get from a food item (Osilla et al., 2022). Calories are not the “bad guy” of nutrition or something we should avoid. By itself, the calorie is neither good nor bad, it is a very useful tool we can use to determine how much food we are eating.

In the United States, reducing calorie intake is often emphasized because habitually eating too much food can lead to becoming overweight and obese (FDA, 2022). On the other hand, consuming too few calories can also lead to negative outcomes. Weakening of the heart, reduced bone density, low blood sugar, and even interrupted sleep can all be caused by under-eating (NCED, 2019).

 How many calories should I eat?

Individual calorie needs are highly variable, as no two people are exactly alike. Some people may not need to consume 2,000 calories every day, while others may need more depending on a variety of factors. (FDA, 2022). Those with certain medical conditions, such as those undergoing cancer treatments, may be prescribed a diet high in calories so they can maintain their weight and health (Piersol, 2019).

There are several reliable resources like the USDA MyPlate Plan, which can give you a decent estimate of your calorie needs (2020). However, be wary of building your whole diet around one single calculator (Le, 2018). Asking your provider or registered dietitian to help you determine your ideal calorie intake is even better than using an online calculator, as they can help you tailor a plan to meet your needs.


Calories are a tool to help measure the amount of energy we are consuming. While the number of calories you eat is only a single factor of overall diet quality, it is important to consider when building a balanced diet.


Center for Food Safety and Applied Nutrition. (2022, February 25). Calories on the new nutrition facts label. U.S. Food and Drug Administration (FDA).,easier%20to%20find%20and%20use.

Le, T. (2018, July 13). Ask the rd: Can I trust calorie calculators?. MyFitnessPal Blog.,use%20different%20calorie%20prediction%20equations.

Osilla, E. V., Safadi, A. O., & Sharma, S. (2022, September 12). Calories. National Library of Medicine: National Center for Biotechnology Information.

Piersol, B. (2019, January 15). Expert tips for adding calories and overcoming appetite loss during cancer treatment. Memorial Sloan Kettering Cancer Center.

The effects of under-eating. National Centre for Eating Disorders (NCED). (2019, September 2).

United States Department of Agriculture (USDA). (2020). MyPlate Plan. MyPlate.


Image from Pexels by Daniel Reche.