I'm interested in this as well...I read something about it before but it's been a while...I gotta have me some hot sauce in SoCal...Maybe one of out friends will chime in here
Hot sauce is not bad for you! Unless it contains oil. But hot sauce and garlic are good for you. Hot sauce by it's very name is thermogenic and heats you up. This meands you burn more fat. Just pick the brands that do not contain oils or too much sugar and enjoy!
Hot sauce will speed up your metabolic rate. Like the above says just don't have loads of the stuff. It's what I usually use to add to flavour to my chicken. Usually I marinade it with a mixture of hot sauce (tiny bit), lemon juice and thyme.