You use energy no matter what you’re doing, even when sleeping. The BMR Calculator will calculate your Basal Metabolic Rate (BMR); the number of calories you’d burn if you stayed in bed all day.
If you’ve noticed that every year, it becomes harder to eat whatever you want and stay slim, you’ve also learnt that your BMR decreases as you age. Likewise, depriving yourself of food in hopes of losing weight also decreases your BMR, a foil to your intentions. However, a regular routine of cardiovascular exercise can increase your BMR, improving your health and fitness when your body’s ability to burn energy gradually slows down.
I calculated a sample BMR (basal metabolic rate) from one of my campers to be 1281 calories a day.
Your BMR is the minimum number of calories your body needs to sustain vital functions such as breathing, digesting food and keeping your brain, heart and lungs working. So with that said you don’t want to go below 1281 a day.
Here is a formula you can use daily depending on how many calories you plan on burning that day.
Take your BMR (1281) + your activity calories burned – your food calories for that day. So example 1281(BMR) + 500 calories burned w exercise – 1500 =calories consumed that day = -281 calories.
If you are eating more than you’re burning,(your BMR + activity is 2000 and you’re eating 2400) you’ll gain weight. If you’re burning more than you eat, you’ll lose weight.
So if your BMR is 1281 and you burned 800 calories with exercise and you consumed 1973 (per your food journal) your total would be = -108 so you would lose weight because you are consuming less than you are burning.
To sum it up I would stay in a calorie range from 1700-1900 calories a day. Assuming you are burning off at least 500 a day.