This is nonsense. The healthiest populations in the world eat large volumes of carbs and have for millenia. Lumping all carbohydrates under the bucket term "carbs" makes as much sense as lumping all drugs under a single term.

Eating complex, unrefined carbs is overall the healthiest way to get the calories you need to keep your body fueled.

I can only recommend that you go and do some research on the difference between whole-food carbs and processed carbs, because that is a very unhealthy (and unscientific) view on probably the single most important nutrient for the human body taking into account the fact that carbs is literally what evolution selected as our preferred brain-fuel, not ketone bodies.