Strictly speaking, the human body doesn’t need carbohydrates, but after you’ve been eating a mainly carbohydrate diet for years, your body gets used to that, and sends you signals that it wants you to keep eating them.
I think that a first step is to try whole grains instead of refined grains; so substitute brown rice in place of white rice, wholemeal bread in place of white bread, wholemeal pasta in place of ordinary pasta. The idea is to increase your fibre intake, which slows down the rate at which the starches are converted into sugars, and the rate at which your body absorbs the sugars.
Likewise, leave the skins on potatoes, carrots, turnips and other root veg, and eat more raw foods, especially green leafy veg, like celery, cabbage and young spinach and chard.