BMR is a static formulaBMR is calculated using a static formula which takes into account one's height, weight, age and activity level. It does not consider other factors such as bone density and the amount of body fat versus the amount of muscle mass.
BMR for an athlete person with less than 10 percent body fat can be very different than for a person with 30 percent of body fat, although both might be of same height and have the same weight.
But on average, BMR is a fairly reliable number, as not everyone is an athlete, nor an obese person.
So if you are curious what is your BRM rate (by the way, BMR stands for basal metabolic rate) you should visit this link and calculate your rate with a BMR calculator.
Eat at BMR rate to lose weightNot quite true though. While eating less than your body burns is the way to lose weight, eating at BMR rate still isn't the most effective approach. It is recommended to eat 10 to 20% less than your calories consumption is. But this comsumption is not BMR alone. You need to add calories burned during your daily activities. For example - walking, standing up, sitting down, walking the stairs and so on. If you are active and do some kind of sports you need to throw those burned calories into the equation as well.
Rather eat 20% less than your daily calorie expenditure is, not the BMR rateSo, to make thins simpler. If your BMR is 2000 calories daily and you burnt additional 1000 that day that makes it 3000 total. Eating at BMR rate - meaning eating 2000 calories only - will give you a 33% deficit, which can, in turn, be bad for your organism, as such calorie intake is close to starving, and this is never good. Eat 2400 to 2700 calories per day if your daily calorie consumption is 3000 total calories. That's not so close to BMR, is it?
Always eat smart, not just less!