If you have the time and they seem relaxed, you may offer to give them a 10-minute quickie introductory sample class, which includes one or two postures and a breathing technique. During this process, explain the benefits of what you are showing them. It is much easier to digest information by doing than by telling.
These types of kramas or Yoga asana sequences certainly do help to boost students’ metabolisms, burn calories and expedite weight loss. However, it is also important to balance the sympathetic and parasympathetic nervous systems of your students through a regular practice of pranayama exercises, in order to facilitate mental well-being and hormonal balance.