30 January 2022
There are 860 joules in a 255 calorie snack bar. A joule is a unit of energy equal to the work done when an object's velocity changes by one meter per second. The number of calories in a food item is measured using the same unit.
How much energy do you need to power through your day?
Depending on who you are and what you do, you might burn anywhere from 2,000 to 10,000 calories per day. At first glance, that might seem like a lot of energy especially if you only get around 2,500 calories in a day.
The Correct Way to Calculate How Many Calories a Day You Need
This process will give you a rough idea of how many calories you need, but it's not perfect. One big variable is that your activity level might change from day to day. Part of the reason for measuring your body fat percentage is to adjust your calorie intake based on that level.
To illustrate how this works, let's look at three hypothetical people:
Jenny, who weighs 130 pounds and has 20 percent body fat
Andrea, who weighs 150 pounds and has 20 percent body fat
Kyle, who weighs 170 pounds and has 20 percent body fat
Each of them needs roughly 2,100 calories per day to maintain their current weight. That changes dramatically when they lose weight. Here's what happens to their calorie needs as they drop to 15 percent body fat:
Jenny now needs 1,500 calories per day. If she were to keep eating 2,100 calories a day as she continued to diet, it would take her much longer to reach her goal because she would lose weight at a slower rate.
Andrea now needs 1,650 calories per day. Again, if she were to continue eating 2,100 calories per day while dieting down from 150 pounds, she would