Instant Knockout claims the number one spot in best fat burners for men list. And deservedly so, as it is, hands down the best fat burner on the market right now full stop. There's very little we don't like about it. It's a little bit more expensive than some options (but not by much). It's packed with glucomannan (in a large enough dose, unlike a lot of fat burners), which is the best appetite suppression ingredient currently available without a prescription.