A few months ago, I asked Alwyn Cosgrove, C.S.C.S. -- one of the world's top trainers -- to create a cutting-edge fat loss program for Men's Health. And, of course, he obliged. But a curious thing: One of the workouts in the plan featured just two exercises.

That's right: When asked to create a super-effective, calorie-torching routine, Cosgrove gave us a workout that had readers do only a kettlebell swing and a squat thrust. This confused some folks, who wondered, "How can you lose fat with just two exercises?"

Cosgrove's response: "Running is just one exercise, but no one questions that when it comes to burning fat."

(Another great way to lose fat: Avoid The Worst 20 Drinks in America.)

He makes a good point. And in fact, once you understand the philosophy behind Cosgrove's routine, you start to see why it works so well. But first, an explanation of the actual routine itself.

Here's how it works: You do 15 repetitions of the kettlebell swing (you can also use a dumbbell for this), followed immediately by 15 reps of the squat thrust. (See below for descriptions of both exercises.) Without resting, do 14 reps of the swing and then 14 reps of the squat thrust. Continue this pattern until you complete only one rep of each exercise. This is called a countdown workout.