You CAN have mashed sweet potatoes - this recipe for Low FODMAP Mashed Sweet Potatoes with Candied Spiced Pecans shows you how to incorporate them safely into your diet.
Add about 1/4 cup (60 ml) of the milk and all of the butter and begin to mash. I usually start with a hand-held potato masher and then switch to a large, sturdy balloon whisk. Taste and season with salt and pepper and add remaining milk if necessary to make satiny, smooth, creamy yet fluffy mashed potatoes. Sprinkle with Candied Spiced Pecans, if desired. Serve immediately.