I use the Telephone brand psyllium husk. It's basically 0 g carbs per serving because that's all dietary fiber. You can buy it on Amazon: Telephone Brand Psyllium Husk (Sat-Isabgol) 200 Gram https://www.amazon.com/dp/B002MY9E86/ref=cm_sw_r_cp_apa_i_TyD9CbG8VHC3M but I buy it at a local international foods market. I like this brand because it doesn't turn the food I make with it weird colors like those brands that contain the hulls.

I like to add a bit to chobani Greek yogurt with some sugar free maple syrup and toasted nuts for a snack. Provides good fiber.