The old adage is true: You are what you eat. That's why on some days you end up feeling more like a cream-filled Twinkie than the lean cut of beef you aspire to be.

But you probably already know that. That's why, like all of us, you're trying to clean up your act and start eating healthier. But the truth is, that's just not enough. Because if you're scarfing down salads made of iceburg lettuce, tossing back cold-pressed juices, and eating bananas by the bunch, you're eating healthy-ish—but you're not eating smart.

To get the shrink-wrapped abs and three-dimensional arms, the lightning-quick brain and unquenchable libido you need to make every bite of food you put in your mouth count. That means building your diet around the most potent, nutrient-dense, disease-fighting, muscle-growing foods around.

But where do you start? And what foods are the absolute fittest? To find out, we decided to put some of the nation's top nutritionists to the test.

First, we polled 40 of the country's most respected food experts—registered dietitians, college nutrition professors, and authors—asking them each: What are the 10 most important foods every guy should include in his diet for maximum fitness? Then, as the results rolled in, we ranked our experts' recommendations.

We not only tell you which foods made the list, but how much of each you should eat on a weekly basis. So read on to see how you can elevate your nutrition.