Rubbish, people have different metabolisms. I can eat pretty much however I like and my weight always seems to stay in the 190-210 range (I'm 6'3"). Other people of a similar height might eat the same way as me and tend to be much thinner or much heavier.
In any case, from the pictures of Mrs. Edwards that I've been able to find (not many), she looks to be a fairly attractive woman who's perhaps a little on the heavy side of what is considered (unrealistically) ideal in our society.
The common scapegoat for laziness is the metabolism argument. We create our own metabolism. It's directly proportionate to the amount of exercise and the level of intensity. Force a marathoner to stop running and sit on the couch eating potato chips for a year, and he'll change his metabolism and balloon up.