Given the recent thread on Paleo and low carb, I thought it would be relevant to post this latest study showing the superiority of low carb diets in treating metabolic syndrome:
This follows on the NEJM study, and a number of other studies showing more or less the same thing.
My personal point of view here, having used low carb strategies along with weight training and cardiovascular work, is that the low carbohydrate diet, and particularly the LC Paleo diet, is by far the best strategy for fixing the aftereffects of overweight and obesity secondary to insulin resistance caused by the high refined grain modern American diet.
If you are already lean, and you have been lean for some time, there are various Paleo templates that will fit the bill for you, with strong evidence of traditional societies in good health, ranging from high carb (California Natives, Kitava) to high fat (Inuit, northern Native Americans), to anything in between. All avoid refined, processed food, high carb diets make high nutrient tubers the center of the diet.
If you are carrying extra weight, particularly around the middle, you need to fix the underlying metabolic issues, and LC eating, and particularly LC Paleo eating, is by far the best way to do this. Depending on how far gone your metabolism is, you may need to stay on a relatively LC diet the remainder of your life, although you may be able to tolerate, over time, more and more paleo carbs, particularly depending on how much glycogen work you do.
You are unlikely to be able to go back to bread, cereal, and the like (I know for me, whenever I start, my body switches back into massive craving mode unless I carefully manage the process from a severely glycogen depleted state).
What I think creates much of the controversy here is people who used LC eating to fix their metabolism and get in control of eating and health, who then proclaim that LC is the only healthy lifestyle.