i think the suggestion of yogurt is for the ones specifically with live bacteria like Lactobacillus acidophilus
, which might help to repopulate the area involved/help get and keep the balance right. bacteria are funny things though, if they don't like the environment that you put them in, they won't stick around, and it can be really hard to persuade them to colonise.
anyway, plain old pasturised supermarket strawberry yogurt aint likely gonna do it, and cheezewhizz or some other icky products wouldn't be any help either. regular dairy products don't generally contain these cultures from what i've seen.
you can get the same probiotics in other food products though, plus in tablets, powders, etc. you might not notice the taste if you put yogurt in a smoothie, either.
i think cutting way back on sugar is a very sensible option. if you still want sweet stuff, xylitol
has been shown to starve bacteria in ear infections, so you never know, maybe it'd help elsewhere.