When people talk about the calories in food, what do they mean? A calorie is a unit of measurement—but it doesn't measure weight or length. A calorie is a unit of energy. When you hear something contains 100 calories, it's a way of describing how much energy your body could get from eating or drinking it.

KidsHealth from Nemours, https://kidshealth.org/en/kids/calorie.html ×

This number on a food label indicates how much fat is in a single serving of a food. Limit total fat to less than 25% to 35% percent of the calories you consume each day. All fats have 9 calories per gram.

WebMD, https://www.webmd.com/food-recipes/definitions-glossary

Usually solid at room temperature, saturated fats are found in animal products such as meat and milk, as well as in coconut and palm oil. Saturated fat is often used in foods to prevent rancidity and off flavors. No more than 5% to 10% of your total daily calories should come from saturated fat.

WebMD, https://www.webmd.com/food-recipes/definitions-glossary

Polyunsaturated fat is a type of dietary fat. It is one of the healthy fats, along with monounsaturated fat. Polyunsaturated fat is found in plant and animal foods, such as salmon, vegetable oils, and some nuts and seeds.

https://medlineplus.gov/ency/patientinstructions/000747.htm

Monounsaturated fats are healthy fats found in olive oil, avocados and certain nuts. In fact, the evidence shows that monounsaturated fats have a number of health benefits. They can help with weight loss, reduce the risk of heart disease and decrease inflammation.

https://www.healthline.com/nutrition/monounsaturated-fats

Vital for building hormones and cell membranes. Your body makes most of the cholesterol it needs. Cholesterol is listed under the fat information on a nutrition label.

WebMD, https://www.webmd.com/food-recipes/definitions-glossary

Omega-3s are nutrients you get from food (or supplements) that help build and maintain a healthy body. They're key to the structure of every cell wall you have. They're also an energy source and help keep your heart, lungs, blood vessels, and immune system working the way they should.

https://www.webmd.com/healthy-aging/omega-3-fatty-acids-fact-sheet

Eicosapentaenoic acid (EPA) is one of several omega-3 fatty acids. It is found in cold-water fatty fish, such as salmon. It is also found in fish oil supplements, along with docosahexaenoic acid (DHA). Omega-3 fatty acids are part of a healthy diet that helps lower risk of heart disease. Getting more EPA in your diet has positive effects on coronary heart disease, high triglycerides (fats in the blood), high blood pressure, and inflammation.

https://www.mountsinai.org/health-library/supplement/eicosapentaenoic-acid-epa

Docosahexaenoic acid (DHA) is an omega-3 fatty acid that is found along with eicosapentaenoic acid (EPA) in cold-water fish, including tuna and salmon. DHA plays a key role in the development of eye and nerve tissues. DHA might also reduce the risk of heart and circulatory disease by decreasing the thickness of the blood, reducing swelling (inflammation), and lowering blood levels of triglycerides.

https://www.webmd.com/vitamins/ai/ingredientmono-864/docosahexaenoic-acid-dha