Get it right (think about it)
Blake's (and other people's) body fat and muscle mass will not change much on a day to day basis, no matter how much they eat or exercise; true.
However, a persons weight will vary, noticeably, day to day, depending on how much they eat and drink; depending on the pattern and timing of eat/drink activity and other activity. I suggest that one night you try eating a large donner kebab, washed down with four large cans of beer. This is guaranteed to make your weight increase by at least five pounds. Within 24 hours, this extra five pounds will disappear. It's true, I've tried it, it's amazing; where does it go?