If you've got gut problems and acne, I should be very careful about steering clear of all sugar, processed foods, vegetable oils, and cereal grains, particularly wheat. Dairy products often seem to trigger acne for people, too. Professor Cordain has informatiion specifically on acne on his site -- unfortunately, it's not free, though.
Standard dietary advice in these circles will be to cut the "white foods" though. You might take a good probiotic, too.
I think with the comment about "low fat" you've got something to consider though. If you've dropped all the bread and pasta and cut out sugar, what are you going to fuel yourself on? Protein won't be more than 15 to 20 % of calorific intake for most people. That leaves a big gap to fill with no bread. You either have to eat a heck of a lot of fruit (or sweet potatoes) - which is going to spike insulin and so cause weight gain - or be prepared to use a little olive oil, coconut oil, or ghee.