My mother talked me into a very similar program when I was just out of college with my bachelor's degree. The "weight loss" doctor had an almost holyman reputation in our area. I was prescribed a half dozen pills including an amphetemine diet pill, the pill for "nerves" (basically to mask the "shakes" you get from the amphetemine), the thyroid medication, a water pill (diuretic to make you pee) and I forget what the other two were for. There were also vitamin B-12 shots every month.
I did lose weight, but I was buzzing like a hummingbird. I felt like the whole world was moving in slow motion and I was the only "normal" person. My heart also would race any time I tried to exercise. (Oh, that's right, I think one of the pills were to help me sleep at night - didn't help much). I wasn't on the program very long, because my supervisor called me on my odd behavior. I was working on the mental health and substance abuse floors of a hospital. While I wasn't told that I HAD to quit the diet program (because it was technically doctor sponsored), but I was strongly encouraged to stop because she felt my obvious "excelleration" would appear to be induced by illicit rather than prescription drugs (I tend to talk a mile-a-minute anyway, so the uppers apparently made me incomprehensible).
I really think even the short term use of the thyroid medications screwed up my thyroid, because now even though my thyroid hormone levels are always within normal range, every year I have more and more low thyroid symptoms. Also I test postitive for anti-thyroid antibodies which means there is some type of autoimmune process in the works regarding my thyroid, it just hasn't done enough damage to show up definitively yet (at least that's how one rheumatologist explained it to me).