I have been hypothyroid for over 20 years, also on 200mg of thyroxine for that time (which did absolutely nothing for me), my symptoms and weight got worse year by year until 2009 I had a sleeve gastrectomy (weight loss surgery to remove 80% of my stomach).

Only after that drastic a measure and *still* not loosing weight (surgery was 100% successful I still cannot eat more than a cup of food at a time) did I finally find a Dr that agreed that my weight was not related to my food intake and changed me over to T3 medication only.

Thyroid medication won't loose the weight for you, it just makes it possible (not easier) for you to lose weight, but you have to work at it, and far harder than a 'normal' person. Over the years I've done the sub 1000Cal per day, the sub 800cal per day and the fasting eat only one small meal a day diet and all it does is mess up your metabolism further making it easier to gain weight on practically no food intake.

Most people (anyone over 5ft in height) need an absolute minimum 1200cal per day of healthy nutrient dense food to keep the metabolism working - its even more important with any hormone issue like thyroid/insulin (I have PCOS as well, not uncommon with hypothyroidism and something to have checked if you havn't already).

Many hypothyroid people find that a higher protein low carb (vegies and low GI fruit only) and regular small meals keeps the blood sugar stable and allows the hormones to work properly (probably because many hypot people also have insulin resistance which requires a low glycemic diet).

Very, very few hypothyroid people will loose any significant weight (or keep it off long term) without a good diet combined with a reasonably serious excercise program including weight training to build muscle (you won't bulk up) which increases your metabolism.

Take it from someone who has been there and done that - baggy skin will be the least of your worries if you don't start eating properly and excercising regularly.