I have tried a zillion different things to get weight off and keep it off and to be completely honest there is only one thing that ever works for me but it works every time. That is, stop eating junk and stop eating as MUCH. This is of course the most difficult thing to stick to for most people lol. It just takes willpower. I am only 38 but I have had a problem with heart arrhythmias for about 10 years now. As a result, I went through a long period of fear and anxiety, mostly because I didn't yet understand exactly what was going on, and as a result I became sedentary. I sat home in front of the computer for the majority of the day with the phone close by and went out very little. Of course it didnt take long before I gained a bunch of weight. I tried some pills (generally not good when you have heart issues) and even some herbal stuff but nothing seemed to work. Finally I just started eating no more than twice a day and when I did eat, I would eat rhy bread with lowfat butter on it, fruit, carrots, very lean meat etc. and in small amounts. I ate very small portions too. Just enough as to not starve myself or cause other health problems. In about 1 week I noticed a difference. Not only was I not bloated from eating greasy gassy junk food but I actually had more energy and just felt a heck of alot better. In about 2-3 weeks my stomach was getting flatter and my face was already thinning. Mind you this was with almost zero exercise. I'm not recommending that you don't exorcise, in fact you absolutely should unless your medical problems say otherwise. Ask the doctor about that part of course.
There really is no pill to help you lose weight and keep it off. Losing weight is about lifestyle changes including a doctor supervised diet and exercise program. That's how to lose it and keep it off, pills only offer temporary weight loss, it's a way of life.
You can do it, I lost over 80 pounds and still losing by changing what I eat and sticking to a daily exercise routine designed to burn more calories than I take in. It's all about calories in and calories out.
Hope this helps,