Hi Robina, I've had an underactive thyroid for about 10 years perhaps in diagnosed for longer than that thinking it through. Anyway, I've been on 125mg of thyroxin for most of that time. I had my bypass in July of 2011 since the surgery my levels have been monitored more regularly than in the past purely as part of our regular post op checks. There have been the odd fluctuation of the levels but nothing to require any changes to my dosage.
As for weight loss over the years I've tried so many diets, pills etc losing weight only to regain with all the excuses etc we give ourselves. Prior to application for funding I had to weigh on weekly & lost the odd kg here & there at the end of 6mths funding was applied for but I was also given vouchers for a slimming club & joined weight watchers I lost 2.5st pre-op another stone on the pre-op liver shrinking diet. Since then I have lost a total of 8st with another 12lb to go to reach my top end goal for healthy weight to height & bmi ratios. Excess skin may stop that & even my ultimate mid range goal but if I can get to 10st 7lbs & maintain it I will be happy as at my heaviest I was 19st 3lbs. I wore size 20/22 clothes now for the most part I'm in size 10. So yes it does work & we can achieve my struggles have been more in my head than my body combined with family challenges. So go for it enjoy the journey & the best of luck. I feel healthier & happier than I have done in years I have other health problems & most of these have been eased as my weight has decreased, others masked by the weight or other things are now being treated or waiting to be treated. So I'm winning in so many ways & working towards full health again.