Yes both of these chains are fairly flexible likewise frankie & bennys, their menu has options for you to ditch the bun on burgers, salad to replace fries, double up on burgers, breakfast choices are good too, they do omelettes and egg and bacon. Recently I visited and ordered a dessert which came with either custard or ice cream, I said neither as I’m diabetic, waitress bought my dessert with a pot of cream on the side, “just in case that might be ok for you” she said, think she might have had a little bit of knowledge about LCHF maybe