Powdered meals are a great replacement diet for many types of reptile.
These are often popular for many types of gecko including the Day Geckos and Crested Geckos as well as many other omnivores (those that eat plants and insects).
The powdered foods are mixed with water to make up these nutritious diets.
There are many different types of flavours to choose from, you may find that your reptile has a preference for one type over another, so you can stick with what you know they like or offer them a little of everything.