What is the nutritional requirement for a frog?

Answer 1

They need plenty of water and sleep.

Answer 2

Nutrition for Tree Frogs:
"Crickets are the main diet. They must be gut- loaded and dusted. Larger frog species will eat pinkies, feeder fish, and zoophobas. Variety if possible is best. Frog diets are not well researched and it is believed that an eye disease called Lipid Keratopathy that leads to blindness is caused by nutritional deficiencies. Wild caught insects such as June bugs, moths, grasshoppers and pill bugs that are not exposed to pesticides or herbicides may help alleviate the problem."
from this site:
http://members.aol.com/Mite37/TPFROG.html

Nutrition for Horned Frogs:
"In the water dish you can provide some feeder fish for them until they are big enough to eat pinkies. Pinkies can be fed, but remember they are high in fat and can contribute to the Lipid Keratopathy problem that damages the eyes. Some books recommend that you do not have to feed pinkies at all and that feeder fish will be enough to provide the calcium derived from animal bones that's needed. Gut loaded and vitamin/mineral dusted crickets are a good food for them as are earthworms, cockroaches, any number of insects will make a great diet for them. Variety in diet is the best way to ensure that they are getting what they need."
from this site:
http://members.aol.com/Mite37/TPFROG.html

And the Frog Doctor gives this information on Nutrition:
"Frogs found in nature have a very wide variety in their diet. For example, poison frogs lose their toxicity when they are bred in captivity because their diet is no longer as diverse as it would naturally be. Realistically, we can't provide the complete variety that would be best, but keeping this in mind is a good idea. Crickets tend to be the most available food, and generally make the basic staple for frogs. (Some frogs require much bigger lunches, even mice! For that type of info you're best bet is to look it up yourself, since I am considerably too squeemish to deal with that sort of subject. See my Suggested Reading List for some great written sources.) Crickets can, and should, however, be supplemented with special calcium gut pellets, like "Calcium Plus, food for Crickets", that provide the frogs with necessary minerals. These can be found in most pet stores. The best way to do this is to drop some of these pellets in with the crickets several hours before they get fed to the frogs. Then when you go to feed them to the frogs, they will be full of good stuff for healthy froggies! For more info on this: read the section on dealing with Crickets. There are also different types of powders that can be sprinkled on the bugs before you feed them to your frogs. "
Plus lots of other information
http://allaboutfrogs.org/info/doctor/sick.html

Hope this helps