I dont think he is talking about herbal or anything. Probably just normal shisha. Most people describe it as a sweet smoke, and with sweet comes sugar. Mostly because they dont know that glycerin is used to make it taste "sweet".
But regardless, the health effects are minimal. Most of us on here have been smoking for 1 year plus and i dont think i can find one problem of anyones health due to hookah. You yourself should try hookah, it is a very relaxing experience and it helps you get everything in your life sorted out. I will just sit, with some nice relaxing music, smoking, thinking about everything i have to get done in the week, sometimes write a to do list.