You may not be making enough stomach acid. A lot of burping from when you start to eat and being constipated all the time are signs of this. You might try taking some betaine hcl, alone or with pepsin, or glutamic acid with meals, available from health food shops, and see if it helps. There are other types of digestive enzymes, such as pancreatic or plant based ones, but the insufficient stomach acid sounds more likely. First you could try sipping juice of a fresh lemon in water, or some apple cider vinegar and honey in water with meals. Doctors are trained to think that everyone makes more than enough stomach acid and enzymes, but that is not true, especially as people age. Any nutritionist will tell you that. Also, more people with heartburn actually make too little stomach acid, not too much. This is written about in every nutrition book I own, of which there are quite a few. There is a test called a Heidelberg capsule test that you may be able to get through a nutritionist that is the most accurate test of this that I have ever heard of, but if you can't get the test, the suggestions I have made would be definitely worth a try. I would stop taking the diet pill. It can only do you harm. I knew someone on a diet pill that killed her suddenly, and she wasn't all that old. I wish you well. Cynthia