The Harris-Benedict equation is a math problem that helps you figure out how many calories you need to eat every day to maintain your weight. It does this by looking at some important info about you, like your weight, height, age, and gender.
It's kind of like trying to figure out how much gas your car needs to go a certain distance. Depending on how big your car is, how much it weighs, and how fast you drive it, it will use different amounts of gas to go the same distance. The Harris-Benedict equation does the same thing for your body - it figures out how many calories you need to use to stay the same weight, depending on your own unique characteristics.
The way it works is by taking your weight and multiplying it by 10 if you're a girl or by 11 if you're a boy. Then you add in your height, multiplied by 6.25 if you're a girl or 5 if you're a boy. After that, you add in your age, multiplied by 5 if you're a girl or 6.75 if you're a boy. Finally, you either add or subtract a certain number of calories depending on whether you're very active or not very active.
Once you've added all of those factors together, you end up with the number of calories your body needs to stay the same weight. It's important to note, however, that this number is just an estimate - everyone's body is different and might use calories differently, so it's just a starting point.
Overall, the Harris-Benedict equation is a helpful way to figure out how many calories you should eat in a day to stay healthy, but it's always a good idea to talk to a doctor or nutritionist to make sure it's the right number for you.