I lost almost 60 pounds last year. Put a few back on over the holidays. I went from a size 26 to a size 18 in jeans. We went on a low fat diet (keeping the fat content under 28 grams a day). You can actually eat very well lots of fresh veggies and fruit, chicken, fish and really lean pork. I cook with a non stick spray (Pam), an very little olive oil when making stir fry. For our sweet tooth I make a really low fat crumb cake made with applesauce and skim milk. For snacks we eat fruit and munch on popcorn.
And an added plus to this all ...all my old "fat" jeans are going to be a denim quilt someday.