If you have a "slow metabolism" eat one candy bar's less worth of calories and you'll be fine.
Nine out of ten humans will be within 10% (less than a candy bar) of what an online BMR calculator spits out based on their sex, age, weight, and height.
The tenth out of ten humans is the person in the article you linked to, or an elite athlete.
If you are one of those one out of ten humans, you are or should be under the care of a physician.
Everyone else can count calories and adjust based on their observations.
BMR has the same factoid-spouting prigs as BMI. Yeah, we get it, you're a powerlifter so BMI doesn't work with you. Shut up and let the 99.97% of the population for who it works use it.