At the very least it seems to me like the average value is roughly balanced. Anecdotally, people seem to change their eating/exercising habits more frequently t

At the very least it seems to me like the average value is roughly balanced. Anecdotally, people seem to change their eating/exercising habits more frequently than they undergo dramatic shifts in their weight. In the long run, you can expect your net calorie balance to be zero - you'll lose or gain weight until your BMR equals your net calories. Based on that, and using [1], a 5'10", 25-year-old male weighing 150 pounds would have a BMR of ~1720. If they add 250 calories (approximately 1 snickers bar) per day, they would initially gain about 2 pounds per month and asymptotically approach their new, heavier weight (~190 pounds, >40 pounds more!). If instead they added 250 calories per day worth of exercise without compensating with more food, the opposite would happen, and they'd eventually lose 40 pounds. It's not like you never see this sort of thing, but it seems to me like most people tend to maintain a pretty stable weight, which makes me think that on average we have some natural inertia when it comes to weight loss or gain. 1. http://www.bmi-calculator.net/bmr-calculator/ http://www.bmi-calculator.net/bmr-calculator/