The are a lot of people out there that do not gutload live food prior to feeding. This might work for them, but it is definitely not good for their reptile. Without food, the live feeders are empty exo-skeletons, with no nutritional value. Gutloading for feeders (crickets, mealworms, superworms) can all been done the same way.
What you need:
Container or aquarium
Bedding (Oat, Bran)
A top (Especially when dealing with crickets)
All sorts of vegetables

How to:
Gutloading is simple and easy to do.

First you must create the housing environment for the feeders. This can be a rubbermaid container, 10 gallon aquarium, or other type of container/housing.

Second, a lid must be present. For rubbermaid containers, holes should be drilled into the top, or the top center can be cut away and replaced with screening. An aquarium should have a screen lid, which fits snuggly.

Third you want a base substance for the feeders (Worms in particular). This can be Oats, Bran, and other things. I use a mixture of oats and wheat bran with my feeders. I give them about 1-2″ of area to dig into.

Forth is a type of vegetable, multiple kinds if possible. You will want potatoes, carrots, kale, collard greens, basically anything listed in the iguana salad menu. This needs to be taken out after 24 hours to prevent any spoiling.

Finally you can add your feeders.

Always keep some sort of vegetable within the enclosure, whether it is a piece of potato, a carrot, or something else. This will allow the feeders to get water.