The Sun produces energy by running thermonuclear reactions. But most of it's mass are protons and proton+proton fusion is the least efficient of all. Of course there are reactions with complex atoms, but that is quite minority.
So, let's make a simple math. According to wiki and some more websites, power output is about 3,827×1026 Watts. Mass is said to be about 1,9891×1030 kg. That makes about 1,92x10-4 Watts per kg.
For ilustration, imagine a man of weight 100 kg. That man has to pull 19,24 gram thing one meter far from it's original position by one second to have the same watt/kg output. Right? Well, according to some sites I visited, human metabolism radiates heat (depends on temperature, weight and many other things) about 100-200 W, which is anyway much more heat/mass than our star.
Ok, now stop thinking about Sun made of human bodies xD. Funny fact, isn't it? So do you still think it is so powerful?