Hello??? I don't know where you got that from my friend but I've been looking at the content of wild snake and lizards scats for years and I can assure you they are actually scavengers in their natural state. As well as favouring specific flowers, nettles, insects and spiders they will eat pretty much everything they come across they consider edible including small snakes and lizards, they'll even take small rodents.
The staple diet for all my lizards (including, different species of beardeds, water dragons, large and small skinks and even monitors) for the past 30 odd years has been canned puppy food and I've had animals live, breed and maintain excellent health well into their late teens to early twenties depending on the species. I think you'll find that despite what you might be led to believe it's also the staple diet for most lizards in Australian fauna parks and zoos.
I mix broccoli, soft peas and grated carrot every three or four meals but they will gladly munch down on straight canned puppy food. They also love their little treats of hoppy mice every other week.
Cheers,
George.