the growth of our Uros is something that i anticipated, given the previous lizard results we have seen with monitors and Gilas. to capture, once again, what i think is THE MOST IMPORTANT bit of information i can give...
"ANY GOOD LIZARD INFORMATION is GOOD LIZARD INFORMATION FOR YOU!"
(good gravy, this is SO IMPORTANT!!!!! i hope lots of folks read this post, and really try and UNDERSTAND what this means!)
this means that with critical thought and application, you can take successful ideas from other lizard husbandry (and even snake husbandry) and apply it to your own species.
it may not apply word for word, you can't say that Uros eat greens, therefore i am going to start feeding my Afrikan monitor only greens. it is the THEORY that applies 
for example, you could take a lot of the detail from my recent Water Monitor article in Reptiles magazine and apply it to the Uros. properly and intelligently apply it, but apply it nonetheless. you can take a LOT of the info from our site's FAQ and apply it to Uros, absolutely. lizard lizards lizards, apply apply apply!
so anyway, food and growth theory...
"keep 'em hot and feed 'em a lot!"
lizards need two basic things to grow. calories(nutrition) and metabolism(heat). with enough access to proper temps, they can digest just about anything. Frank Retes from the Goanna Ranch says that with enough heat monitors could eat and pass doorknobs. that is a figure of speech, but not far off.
that is why impactions are of little concern. with proper heat gradients, lizards can digest dirt, soil, and sand (twigs, hair, bones, stems, whatever) easily.
with maximized digestion capabilities, the animals can process a lot of food. nutritional calories (as opposed to empty calories) equal health and growth. we let the growing lizards set their own diet. they can eat as much as they like. all that intake is turned into growth, and the animals really thrive, in fantastic health.
our actual diet probably isn't that much different than what most folks offer here. we have yet to offer insects or meat, it has all been veggies. greens, veggies, lentils, a bit of fruit, etc. and a good supplement (MinerAll)
i AM thinking of branching out into the meats a bit, to see what is possible there. i don't buy for a second that a Uro in the wild would turn down a rodent that has fallen into the four foot tall burrow entrance. certainly they would be opportunistic feeders to some degree (the rodent idea raised by Dr. Sprackland).
anyway, our 4 grams to 120 gram in 4 months rate didn't seem that odd to me, because i have seen it with other lizards. it is fairly common for experienced monitor breeders to raise hatchling animals to breeding size and get viable eggs within a single year. we regularly raise Blackthroat and Water monitors to well over 4 ft in a single year, no sweat.
that growth rate with Uros is much more rare, because (i believe) folks aren't idealizing their setups. once again, it is not just one piece of the puzzle (soil) that opens up that possibility, it is the whole picture.
give the animals a good setup (soil not only burrows, but helps eliminate stress!), give them great temps (our temps go near 150F) and give them plenty of food, and there is your growth.
take one of those pieces (or other more subtle pieces) away, and you have poor growth. lots of food does no good if the animal doesn't have the proper basking spot or access to the spot to get the metabolism up.
a super basking spot doesn't equal growth if there is a shortage of food.
a stressed out animal will neither bask properly or feed properly, so a stressed animal in a "great" setup may not grow either. and in that case, the setup may not be so "great" after all, right?
there is no simple answer to say, "just feed more food" or "just feed bacon and peanut butter every third day". it isn't a secret diet ingredient that gets the growth, and healthy, thriving animals. it is a great setup, and giving the animals (Uros in this case) all the TOOLS they need to achieve life events in the most efficient and healthy way possible.
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robyn@proexotics.com
Pro Exotics Reptiles
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