Diet
Rattleshakes naturally crave food related to their contents. For example, one with a hot chocolate core will find itself munching mostly on chocolate and drinking milk. While this does not replenish the liquid inside in quantity, it will help keep it well saturated and healthy. Returning to the hot chocolate core example, the brown of the hot chocolate may grow less saturated over time if the individual is not eating enough. A lemonade core may be watered down without lemons, etc. This affects health, and will make the lamia sluggish until they refuel.