Pointing out something that either IS obvious or SHOULD be obvious:
There are plenty of ways to construct a vegetarian diet poorly, so those are mistakes you should watch out for and be on guard against.
Processed carbs are pretty much garbage. For whatever reason, once you process a grain into a flour, it becomes less filling and easier to overeat. I dont care if its wheat flour or rice flour or oat flour — still kinda junky in my book.
Intact carbs are fine in moderation, like brown rice, potatoes, rolled oats and the like. But! Obviously if you use a grain as a base, and then dump crap all over it, then the whole thing winds up being a bad idea.
Like, a “loaded” baked potato can easily become a cardiac event on a plate. Or, a bowl of oatmeal can turn into a monstrosity when the oats become a backdrop for five different kinds of sugars and fats.
I am a longtime vegan, and it is not so much the exclusion of meat that has been a positive thing, but rather, the exclusion of processed calorie-rich junk, that has made the difference. So a simple stance against eating animal flesh is fine, but won’t in itself improve your health in any way.
Some of the vegan athletes seem to do it mostly right (sage canaday, rich roll), but there are countless other people overdoing it on junk and pretending it’s a “better” way to eat.