
Originally Posted by
gbrice75
It's really not possible, at least to a science. Firstly, the number is going to be different every day, albeit small changes assuming your activities change very little.
A better question would be "how is it possible to know how many calories I need to maintain my exact weight?". This is still tough to get down to a science, but if you did the exact same thing every day for let's say a month, and ate the exact same diet during that time, you would either gain, lose, or maintain. If you gain weight, reduce calories slightly until you stop gaining. Vice versa if you're losing. Once you maintain, you'll know your TDEE/maintenance calories.
However, it should be noted that THIS number too will change, based on activity and body composition changes. Also, it's unrealistic to assume that activity and diet will be exactly the same, every single day.