100g a day isnt much. if its working for you rock it brother! Everyones tolerance to carbs and their insulin response is different. I think some suggest cutting carbs out totally or just veggies, then slowly adding stuff in until you realize its not keeping you lean as you want, then you know at what point you need to keep carbs under to keep lean or drop chub.
I actually take carbs at times even if Im strict meat and veggies, say a light carb sports drink with whey protein in it, and a handful of BCAAs, beta alanine, and creatine during a training session, then after a big protein shake and resume meat and veggies diet.
I think everyone is different and there is no set protocol cookie cutter for all of us to follow...surely folks have been getting lean and ripped while using wheat products, yams and potatoes, and rice for years!