If you cut calories too much your metabolism starts to slow down, but with gastric bypass you are taking someone who normally eats 3000 or so calories a day and cutting them down to 1100 or less a day. How do doctors avoid them having a metabolic slowdown and all the negative consequences associated with it like burning muscle mass and chronic fatigue?
IANAD, but I’ll give this one a shot. I don’t think the docs do stop this phenomenon; but, if you reduce caloric intake enough, you lose weight, metabolic slow down or not. Have you not seen photos of concentration camp victims? Like skeletons with skin. It’s because they got so few calories. Did their metabolisms slow? I’m sure they did. But not enough to offset the drastic reduction in caloric intake. After all, if metabolic slow down worked perfectly, no one would ever starve to death.
Also, I don’t know how significant this is, but gastric bypass is not just about reducing caloric intake, it’s about allowing the body to absorb less of certain things, like fat.