I think for people who have no clue about nutrition, a program like Weight Watchers which is heavy on the group support, could be useful if they can stick with it. So many people just don't want to go thru the trouble of learning about their bodies, planning their food (look how many posters here get whiny when told to plan in advance!), eating sensibly, etc.
I'm sorry for your aunt, in a way, cuz it's very frustrating to tbe told such stupid advice (1 chip, my ass) and feel like a failure all the time.