Nutrition 101: Calories

by Elle Penner, MyFitnessPal Registered Dietitian

This article explains the relationship between calories and just how they add up to pounds, kilos or stones.

Calories come from macronutrients, which you may know as carbohydrates, proteins, and fats. Macronutrients differ from micronutrients in major two ways: they are required in large amounts by the body and provide energy. Micronutrients are required in much smaller amounts (hence the micro-) and have important structural and functional roles but don’t provide energy.

A diet balanced in these three macronutrients is essential for meeting the body’s broad needs. For example, carbohydrates largely fuel our brains and physical activity, proteins are used to build and maintain lean muscle, and dietary fats contain necessary building blocks for all cells in the body.

You’re probably well aware that consuming too many calories leads to weight gain. Eat too many calories from any of the three macronutrients, and they’ll be converted to fat. Conversely, consume fewer calories than you expend and those fat stores will be used up to produce energy. Weight maintenance is the fine art of energy balance.

It seems very calculated, but equating calories to pounds of fat is just an accurate approximation.

Here’s a quick overview of the math:

• 1 pound of fat tissue weighs 454 grams
• Approximately 87% of fat tissue (or 395 grams) is fat. The composition of fat tissue may vary slightly from person-to-person
• 1 gram of fat provides about nine calories of energy, though studies have shown it ranges from 8.7 – 9.5 calories per gram
• 395 grams of fat at nine calories per gram adds up to 3,555 calories per pound of body fat, which is rounded to 3,500. 1 pound is roughly equivalent to 0.45 kilograms or 0.07 stone.

If you use MyFitnessPal to track your nutrition intake, you know just from inputting portion sizes that this is also an approximation. At the end of the day, though, being able to look at a rough estimate of calories consumed from carbs, proteins and fats, compared to what our bodies roughly need, is an excellent way to find the balance in energy balance.

See our Calories Infographic (English only).