Yes indeed. A lot of commercial GF food is, if anything, higher in fat and sugar than the "regular" gluten-containing equivalent. Just because a product is "free from" something-or-other (whether gluten, lactose, nuts, whatever) doesn't mean it's healthy.

We've gone GF at our house because my wife has coeliac disease. But we use very few commercially-prepared GF products; we cook at home from basic ingredients, and simply avoid the gluten-containing grains.

If you basically went gluten free by relying on products from the supermarket "free from" section, I can imagine it's easy to gain rather than lose weight.