Lots of exercise and physical activity is the most important thing for maintaining a healthy bodyweight. Sedentary lifestyle is the No.1 cause of obesity... If you are extremely active then your body will use everything you eat for energy and your body won't even have a chance to store enough fat to make you obese. Splitting hairs and debating about what the proper macronutrient percentages are, is BS. As for paleo, there is enough evidence that starch was part of human diet long before humans settled down and became farmers. So yes, eating starchy roots is very paleo.