Quote:
Originally Posted by Lori Bell
This is a tricky question. Every year thousands of Doctors preform bariatric surgery on hundreds of patients each. (In the US alone) Patients are put on extremely low calorie diets before and after the surgery, and for some reason these people lose massive amounts of weight. Seems to me that if a low calorie diet was so terrible for a person, that all those Bariatric surgeons would be getting sued out the ying-yang. It also would seem that WLS would be totally unsuccessful if eating too few calories caused people to binge, and stall and go into starvation mode, and all the other things I hear people say about a 1200 calorie diet. But, for some reason each year the number of WLS patients dramatically increases. I wonder why that is?
I would argue that the wls statistics actually confirm compromised metabolism. By most estimations at least 50 to 60% of wls patients eventually regain to their prior weight or HIGHER. If metabolism weren't affected this shouldn't be possible - at least not unless the person were to eat significantly more than they ever did before the surgery. For surgeries in which a good bit of the digestive system is either removed or bypassed, "logically" even if the person didn't change their eating or exercising habits at all, they should see a dramatic weight loss, just from the effects of rerouting the digestive system - but that's not what happens.
From what I've read (and people I've talked to), the folks who regained all or most of the weight, say that they must eat far less than they did before the surgery (though certainly more than they were able to imediately after surgery). Again, if their metabolism hadn't been reduced, they should have maintained at least some of their loss by the just by the effects of the bypass itself.
Very low calorie diets "work," (in that they produce weight loss) even WITH metabolism decline, because while metabolism can be SLOWED, but it can't be stopped. You will always be able to lose weight if you cut calories far enough, because your metabolism can never reach zero.
However, if you can lose all of your weight by gradually reducing your calorie count, and end up (just for argument's sake) being able to maintain your weight on 1800 calories, it would be better (by most people's definition) than losing all your weight on 1000 calories, and end up having to eat fewer than 1500 calories to maintain your weight.
There's a good deal of evidence that metabolism CAN be reduced by low calorie dieting (especially very low calorie dieting - under 1200 calories), and also repeated gain/loss or yoyo dieting. What isn't so clear, is whether the effect is inevitable, who may be more or less likely to experience metabolism decline, and whether the changes are permanent or what factors can minimize the effects or change the course.
I've read some research that suggests that metabolism can rebound by increasing muscle ratio through exercise (though it can be difficult to exercise on very low calorie levels). Very low calorie diets also increase the risk of dieting-related complications (some dangerous, some just unpleasant) such as pulmonary hypertension, mitrovalve prolapse, cardiac arrythmia, water intoxication and other electrolyte imbalances, mild to dangerous low blood sugar drops, blood pressure changes, gallstones and other gallbladder issues, hair loss, vitamin and mineral deficiencies or malabsorption problems).
There may be others, but those are all the ones I can remember.
The best reason against very low calorie diets, is that there's a great deal of research support for them being the least effective (at least without weight loss surgery that removes or bypasses a good deal of the digestive system).
There was just a recent study that I believe found that the most effective dieters in the groups tested only reduced their daily calorie level by about 250 from their maintenance level (I haven't read the actual article yet, so I may be wrong here, though there's a good deal of other research that has found "in general" that gradual changes often are more successful than drastic ones).