"Much" is kind of meaningless here. If you increase your BMR by 100 calories a day that's huge because losses or gains are made at the margins. My main point i

"Much" is kind of meaningless here. If you increase your BMR by 100 calories a day that's huge because losses or gains are made at the margins. My main point is that you need something that's not optional. If you cycle to work once a week that might be a 300 calorie deficit and it's not some sort of task you can "fall behind on", it's an integrated part of your routine now that you'd have to deliberately not do. The specific example doesn't really matter, more just that it's not some fad "I'll make myself suffer at the weekend on the treadmill" or whatever.