From my experiments with the JVM that is not really true. Keeping memory usage below 1GB is pretty easy. It's only getting tricky when you want to go below 200MB. You'll have to deal with the overhead the JVM introduces. As a result I often just use lua for really simple programs and I am rewarded by creating programs that use less than 2MB of RAM.

Which Lua kind/runtime you're using that give you such frugal programs? I'm intrigued (pun with your name intended).