DAVID ZINCZENKO AND TED SPIKER
THE HOOK: If you've got a six-pack, you're probably healthy.
THE DIET: Lots of protein and good fats, no refined carbs. Accompanying workouts blast those abs!
NO. 1 LESSON LEARNED: Healthful meals can be tasty and easy to make.

Zinczenko is the editor-in-chief of Men's Health and the guy behind the bestselling Eat This, Not That! books. Where some diet authors wrap serious packaging around bubble-gum advice, Zinczenko has found success putting bubble-gum packaging around smart service. His strategy here is whole foods and a schedule of three small meals and three robust snacks per day. Follow the guide, Zinczenko says, and you'll lose weight without losing your mind. And thanks to lots of protein, plus the included workout plan, you'll emerge faster, stronger, and more swimsuit friendly.

I had a basic shopping list—peanut butter, chicken breasts, whole-grain bread, tomato sauce, spinach, milk, eggs—and recipes that rarely required more than 20 minutes. Plus most breakfasts were smoothies and most lunch and dinner recipes provided extra servings I could freeze or refrigerate. This diet destroys any arguments about how eating well is too time-consuming.

One big takeaway: Snacks are best used to prevent hunger, rather than to address it. A handful of nuts, a slice of melon, or peanut-butter toast a couple of hours after each meal kept my energy levels even throughout the day; whenever I worked out, I was adequately fueled.