The body shot, or liver shot, is one of the most underutilized techniques in modern MMA. Too many fighters get caught up In looking for the one shot knockout. Too many fighters have hurt their opponent only to wear themselves out by swinging for the fences. When you hurt someone with a strike to the head they are naturally going to cover their head. They expect you to attack the part of them that is most vulnerable, it's a very predictable thing to do.
Choosing to strike the body also has the benefit of,not only hurting your opponent, but also taking away their cardio. By continually striking your opponent to the body you will eventually wear them down. You are not only causing them pain, but making them tired as well. This is not the same as strikes to the head, of course you can cause damage but you will not wear them out as much as if you go to the body.
The body is also not nearly as easy to move as the head is. It takes minimal effort to move the head and considerably more effort to move your whole body. Forcing an opponent to move to avoid a body shot will also wear the opponent out. Not only does the body shot have direct effects, it also has indirect effects. It gives your opponent another thing to think about and opens them up to other strikes and possibly takedowns.
So please, take a page out of Bas Rutten's book and use more liver shots!