Most of us know that the amount of calories we consume has a direct effect on our weight, but why? What are calories, and what is their function in terms of health and weight management?

These important questions highlight how crucial it is to understand the calorie and how consuming them impacts your body. That’s why, in this installment of Simple Food Terms Explained, we revisit the term “calorie” and take an in-depth look to help you make smart dietary decisions.

What Are Calories?

Calories are a unit of energy both consumed by eating and expended through physical activity. Everything we eat and drink contains a certain number of calories based on three essential macronutrients:

  • Carbohydrates
  • Protein
  • Fat

Each of those macronutrients has a specific calorie value per gram. While carbohydrates and protein contain 4 calories per 1 gram, fat contains 9 calories per 1 gram. These numbers are key when calculating a food’s nutritional value.

Not only does the number of calories you consume play a huge role in overall health, the quality of those calories is important as well. Humans are great at survival, but we function best with a balanced ratio of carbs, protein and fat from healthy sources. Sadly, the carbohydrates in the candy bar you had for lunch are not the same nutritionally as the carbohydrates from a banana.

What Role do Calories Play in the Human Body?

When we eat blueberries or drink orange juice, those calories become the fuel for the day’s physical activities. We all require a certain amount of calories (energy) to support the body’s essential functions. Even when we sleep, our bodies consume calories to pump blood from the heart, keep our lungs functioning and to fuel several other important processes.

Because calories are a unit of energy at their core, it is true that consuming 2,000 calories per day from ‘junk food’ will have the same effect on your weight (not health) as 2,000 calories from nutritionally dense foods. This is because one pound in terms of body weight is equal to 3,500 calories. So, we must burn or consume that amount in addition to the calories our bodies need to function healthily to either lose or gain just one pound.

The reason you should choose to get your calories from foods rich in nutrients relates to your body’s general health. If you’re purely counting calories and eating the foods that are lowest in them, you will miss out of essential vitamins and minerals that come with a higher calorie content.

Safely Reducing Calorie Intake

It may seem difficult to pin down your exact dietary needs, but safely reducing your calorie intake is relatively simple, with the help of a registered dietitian. The best approach for safe calorie reduction is:

  • Determining how many calories you need per day to maintain your weight,
  • Deciding how many calories you need per day in addition to gain or lose weight, and
  • Adjusting your diet to reflect your caloric needs.

In general, those aiming to reduce calorie intake can safely lose about 1 pound a week; weekly weight loss above two pounds is not recommended without supervision from a doctor.

This translates to a 3,500-7,500 weekly calorie deficit (or 500-1,000 calories per day), depending on your calorie reduction goals. This deficit also has to come from your daily maintenance caloric needs, which is most likely not exactly 2,000 calories a day.

How do you calculate the amount of calories your body needs to maintain your current weight? The easiest way is to use an online caloric intake calculator from a reputable source. Keep in mind these values are still estimates, so be sure to track your progress to make sure you are meeting your goals healthily.

For a more accurate number, a visit to a nutritionist. A nutritionist can run tests and/or use equipment to give you the most accurate caloric intake number that is currently possible. Or, if you are not in a hurry, slightly adjusting your diet weekly and tracking the results will work as well.

Healthiest Foods (per Calorie)

Cutting back on calories doesn’t mean you need to cut back on filling and nutritious foods. There are some power foods readily available that can help you meet your weight goals and provide a healthy diet.

Some of the healthiest foods per calorie are:

  • Salmon: high in Omega-3 fatty acids, protein, magnesium and other various vitamins
  • Kale: very high in vitamins C, A and K
  • Garlic: high in various vitamins and Allicin, a nutrient that helps to lower blood pressure and cholesterol
  • Liver: very high in vitamins (especially the B vitamins), protein, and excellent for metabolism
  • Blueberries: high in antioxidants and vitamin C, and some studies suggest they may help fight cancer in the body