if you consume more energy than your body needs to function, you will gain weight. this can be pretty tough to do while eating primally, so you need to make fat your new best friend. with each gram of fat your are downing 9 calories, which is why it's so easy to stay satiated on the PB. so add more fat wherever you can...butter, oils, etc., and you can probably create a little weight gain with increased carbs too. sweet potatoes are the winner for me, but look at some squashes and fruits too.