There is nothing else. Basically, calorie restriction works, and nothing else does. I recommend Fight Aging! if you are interested.
We don't even know that for sure. There were two big studies in rhesus monkeys which disagreed on that.[1] Evidence from mice, where this idea originated, is dubious at best considering the mice most studies use.
[1] http://www.nytimes.com/2014/04/02/science/a-new-salvo-in-deb...
To prove "slowing aging", you need to demonstrate increase in maximum lifespan, not average lifespan. Exercise, diet, etc. increase average lifespan. There is no evidence they increase maximum lifespan, none at all.
Common sense, while harder to study in a lab than a new specific medicine XYZ, actually can serve us well in the messy real world.