Commonsense, my dear, I have followed your blogs since forever and usually marvel at how much you seem to know about EVERYTHING, but methinks you have traversed into an area about which you're not quite as learned. People do gain weight for a variety of reasons other than overeating and no exercise. Thyroid disease is one. Medications taken for various illnesses are notorious for causing weight gain. There are many others, but I won't bore you with the list.