Your BMR (Basal metabolic rate) is the calories you require in a day sans any activity. It’s a starting point for the calories you need to survive in a day. Eating less than this is not advisable in the long haul since it is bad for your health. The calorie requirement is more contingent on how much body fat you are carrying rather and not just your sex, ethnicity or race .

You can’t control your BMR, it’s a basic function of your height, weight and body composition. The Cunningham equation also known as the Katch-McArdle is one of the preferred starting points for determining your basal metabolic rate (BMR). But here are the ways in which you control the number of calories you burn:

1. Calories spent digesting food - thermic effect of food
2. NEAT - non exercise activity thermogenesis 
3. Calories spent on exercise - thermic effect of exercise

For the population as a whole, height, weight and body composition are largely predictive of BMR. There is very little variance to it. Some medical conditions are the exceptions. But largely two people with identical height, weight and body composition will have similar BMR’s.

The thermic effect of food is what makes gives higher protein diets a small edge for fat loss. If you eat 100 calories of protein, anywhere between 10 and 30 calories are spent digesting the protein. This effect is less pronounced in carbohydrates which require 5 to 10 calories per 100 calories and fats which require almost no calories to be digested. The greater the protein intake in a diet, the higher the thermic effect and the calorie deficit is a little bigger everyday. This adds up.

Calories spent on exercise depends on intensity and experience. But you can find an rough estimate of the number and adjust it. 
If thermic effect of food is a pigeon pulled out a hat, NEAT is the 200 million dollar Avengers production. This is the number which people refer to as ‘a higher metabolism’. It is all the activity you do in a day which is not exercise. And it adds up. A walk to the local shop here, climbing a few flights of stairs to hang clothes, taking your dog for a walk, carrying your own groceries etc etc. An entire industry of trackers which are largely crapshoots were built on the idea that if NEAT could be measured as steps, it could be quantified. But even hand gestures, fidgeting with your leg under a desk seem to add up. And this is the biggest variable or differentiator between people. You might not be able to control how much you fidget under a desk but you can choose to make it a walk to and back to your local store instead of a car ride. It adds up.