Lassi, on the other hand, is thicker than chaach. It contains more fat and is high in calories as it is sweet in taste. To make the lassi more flavourful, rose syrup, mango, kesar and khus are added on top of it. Lassi is heavier than chaach and can make you feel fuller for a longer period of time. Being rich in probiotics, lassi also helps solve digestion issues such as bloating and constipation.