I am the first to admit that I used to be a total carb addict. Oatmeal, brown rice, pasta...I couldn't live without it...and probably ate way more than I should have...at every sitting. If a proper serving of rice or pasta is 1/2 cup, then I probably ate 5 servings in a single meal! I never saw this as a problem since I was firmly entrenched in the 90s low-fat trend. I kinda laugh at my diet back then, which was not only really high in carbs, but also refined sugar. I used to bake a ton of fat-free baked goods that had tons and tons of sugar. They were delicious! But now I realize, they were not really that healthy.
I probably got away with this without any repercussions because I was young, I always ate whole grains, and because I have always been so physically active. But, interestingly, as I have increasingly shifted away from endurance exercise towards strength training, I've started craving carbs less and protein more. I have also followed the research very carefully and while there is no evidence we need to completely ELIMINATE grains and carbs from our diet, there is growing evidence that we should limit them. Both quality and quantity count.
My carb-iest meal is always breakfast, because I can't live without my massive bowl of oatmeal, but then I try not to overdo carbs as much as I used to. I adore shirataki noodles, sweet potatoes and squash, and am happy to switch out rice for cauliflower 'rice' most of the time. Surprisingly, I don't miss all the carbs. But when I want bread, tortillas or regular pasta or brown rice, I eat it. There is still plenty of research linking the consumption of WHOLE grains to positive health outcomes.
Aside from Dr. Mercola, the other guy I think is a hack is David Perlmutter, who wrote Grain Brain, which garnered so much attention a few years ago. Perlmutter, who at least is an actual MD, claims that blood sugar is linked with dementia, and while this is true, its not solely carbs that are to blame. Carrying around extra body fat causes high blood sugar levels, regardless of what foods were consuming to create the excess pounds. Any diet, regardless of ratio of carbs to fat to protein, that leads to weight loss, will help decrease blood sugar levels. And science disputes Perlmutter's recommendations of replacing carbs with saturated fat. In fact, saturated fat is bad for your brain too! In addition, Perlmutter's claims that gluten is bad for your brain, is also full of shit. Some celiacs can sometimes experience related neurological problems, but this is rare and individuals not sensitive to gluten do not need to worry.
If you are still buying into Perlmutter's bullshit, feel free to pick up The Centre for Science in the Public Interest's Health Action Newsletter for Jan/Feb 2015, where they explain the way he has misconstrued all the data on the grain-brain link.
In sum, I would say the only foods that can be eaten without limit are non-starchy veggies. Go ahead, eat all you want! But pretty much everything else can be overdone...even the healthiest, whole grain carbs, so make sure you are eating an appropriate amount of servings for your individual needs.