Gluten-free sounds hard. No bread, no beer?? Don't know if I could do that, I like my sammiches and my stout. xD Glad it's working for you guys though!
As for sugars, I keep away from trans-fats, eating less overall, and that's working for me. Trans-fat is the stuff they put in digestive biscuits and all those other delicious things, made from vegetable oil and not good for you at all! It cannot be processed by your body so it is stored and harder to get rid of. Saturated fats are much better because they are taken naturally from the animal. Plain sugary stuff is okay for me, infact, on days where I've eaten more sugary stuff, I've lost more weight.
I've been dieting like this on and off for the last 2 years, but when I was actively working to lose weight I lost around 42lbs in that time. I've started again this year to get down to a decent Body fat %age and lost another 6lbs in four weeks.