Well actually I disagree on this When I was running 5 miles each day for the soccer team and gained 30 pounds within a month that was the worst news I ever heard. I was eating right and Running and doing weights and then the drs ran blood tests and I had hypothyroidism and pcos and pre-diabetic. So really yes weight really can come upon a person really fast. I've struggled with my weight since then and have done tons of diets and weightloss programs and none have worked. so now I'm going for my first apt with my surgeon this june and have already done 3 months of dieting.