I used to always wake up with a really dry sore throat on a regular low-fat diet. A couple of times a week I would also wake up with really bad sinus congestion.

Now that never happens to me, excpet for my carb up. when I carb load I get a sore throat and if i go too hard on the carbs my sinuses come back.

Also I used to have to drink non-stop on low-fat diets, like almost a litre every hour, but now I'm rarely thirsty!