I don't have any terrific recipes to share just now, but I gain weight very easily, so I have to monitor my portions and fattening foods.  I learned from doing some reading that eggplant, potatoes, and lentils are entirely fat free.  The fat comes from what you put on them, and what you cook them in.  I found a neat thing to do with potatoes to make a gluten-free snack, but it's labor intensive and time consuming.  I wash and peel Russett potatoes, and then slice them to about the size of what potato chips usually are.  I try to get them as thin as possible, though that is really a challenge.  I put them on parchment paper on a baking sheet.  I pre-heat the oven to between 425 and 450 degrees F (in the U.S.).  I put the sheets on the top racks of the oven.  I have to keep a close eye on them, especially after I've baked a few sheets and the oven and sheets get really hot, but the online recipe called for about ten minutes.  They recommended turning them over after ten minutes and letting them bake for another five, but I find that between 10 and 15 minutes on one side does it for me.  Then I turn them out and let them cool, and store them.  I carry them around as snacks, and I don't put salt on them so that they're a fat-free, sodium-free, gluten-free snack.  I'm pretty sure these foods contain carbs to some significant degree, though.  I believe carbs are broken down into sugar and then converted into fat, but I don't know how fattening that is compared to processed foods or foods containing actual fat.  As for the lentils and eggplant, I boil the lentils according to directions, and I fry the eggplant using PAM or a similar spray.