Basics of Nutrition: Calories

Books, magazines, the Internet, TV, all of them are full of nutrition “facts”. So much of it is misinformation or disinformation. Sometimes it helps to get back to basics. That’s what we aim to do with this new special.

Each week we’re profiling one of the building blocks of dietetics. Whether you’re new to nutrition or a long-time healthy eater, we hope you’ll enjoy this weekly primer on the basics.

This week we’ll talk about calories.  What is a calorie? Fundamentally, it’s a measure of energy. But not all calories are made equal.

Read on to learn more and at the very least you’ll be prepared for the next trivia night.

What are they?
A calorie is the standard unit for measuring energy.  More specifically, it is the amount of heat energy needed to raise the temperature of one milliliter of water from 15 degrees Celsius to 16 degrees Celsius.When we talk about a calorie in nutrition, however, we’re actually talking about a kilocalorie, which is 1,000 times the energy of a true calorie, i.e. 1,000 calories.
Why are they important?
Calories are energy and our bodies require energy to survive.  Without energy, our lungs would not breath, our hearts would not pump, our blood would not flow… you get the picture.
What foods are they found in?
Carbohydrates, proteins, fats and alcohol all provide calories.

  • 1 gram of carbohydrate = 4 calories
  • 1 gram of protein = 4 calories
  • 1 gram of fat = 9 calories
  • 1 gram of alcohol = 7 calories
How much of it is safe to eat?
There is no right answer to this question because everyone’s energy needs are different and are dependent on body size, body composition (muscle versus fat), age, hormones (stress, pregnancy, thyroid conditions), medical conditions and diseases, environmental temperature, diet composition, and activity level.  Research centers and hospitals often use costly methods to estimate energy requirements, but these aren’t usually available to the rest of us.  Instead, we use equations, like the Harris-Benedict formula, to roughly estimate how many calories we should eat.  These formulas take into account resting energy expenditure (REE), which is an estimate of how many calories your body needs to function at rest, and your activity level.
What’s the most common myth about them?
In my opinion, the most common misconception about calories is that they’re all nutritionally equivalent.  For example, a serving of gummy bears has roughly the same number of calories as a medium sized banana, but these foods are hardly interchangeable.  The gummy bears provide a whopping 20 grams of added sugar (See “Beware of added sugars!”) and zero nutritional value.  A banana provides important vitamins and minerals, like potassium, and fiber to slow the absorption of sugar.  Plus, a banana is much more satisfying whereas a handful of gummy bears will leave you hungry for more.
Anything else I should know?
Eating more calories than your body needs on a regular basis will cause you to gain weight.  It doesn’t matter if these calories come from carbohydrates, protein, fat or alcohol. Pretty basic.

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