With special thanks to Gareth Wallis at the University of Birmingham, UK.

First, you may want to read up on what exactly a calorie is, and why our bodies need energy in the first place. To figure out how many calories you require on a daily basis you need to understand your basal metabolic rate (BMR)—the amount of energy you burn while you’re in a resting state. Several factors shape your basal metabolic rate, and the best way to learn about those is to calculate your own. Here’s a good explanation from the Mayo Clinic on the role that metabolism plays in burning calories.

All this helps us build up a clearer and more detailed picture of how many calories each of us needs every day—though the averages by gender are a good starting point. Everyone is unique, however, and that means we need a unique number of calories too, dependant on our age, height, weight, gender, and levels of physical activity. The right number of calories can help you achieve an energy balance, so it’s good to know how many you actually need. You may want to use the Mayo Clinic’s calorie calculator, which will tell you if you’re consuming too little, too much, or just the right amount. And, if you’re interested in finding out how many calories are in your food before you eat it, you can type almost any product into this counter, or this one. Both will estimate the amount of energy your food contains.

But remember, it’s not all about energy intake: nutrition is an important factor in what we eat, as well, because it provides us with the variety of vitamins, minerals, and other ingredients we need to remain healthy. If you’re keen to learn more about this topic, you can take a look at TED-Ed’s selection of nutrition videos, where you can explore everything from the effects of sugar on the brain, to the chemistry of cookies.