Root vegetables are usually higher in carbs. For my diet, i stay away from them. I second the substitution is key to stay under your carb daily limits. Instead of mash potatoes, you can make it out of cauliflower. Lost 30 pounds, over a year with lots of cheat day/weeks.
Low carb diet does make a big difference losing weight but watching net calories makes a bigger difference. If you're 500 calories under the maintain level. You'll easily drop a pound a week. Combine with some light daily exercises and you get that close to 2.
My personal strategy is not counting but ranking and never eat something worse if I can eat something better. So I could roast some potatoes, but why not just buy carrots that are practically on the same shelf at the store?