Personally, I think it's a good thing to alter your carb levels up and down.... your body will adapt to any plan if you stay on it long enough. Going up to 40 carbs for a while is fine.... when the weight loss slows down, you may want to go back down to 20 again. When it slows down, go up to 60....then back to 20. Why not? Play around. See what works for you!