Dietitians say that vegetarian diets, like those designed by whole food nutrition experts, could provide preventive health benefits for those who adopt them.

In a new position paper, the American Dietetic Association says that "vegetarians tend to have a lower body mass index and lower overall cancer rates," adding that people benefit from "the diets [which] tend to be lower in saturated fat and cholesterol."

Chief among the benefits are increased levels of fiber, magnesium and various plant-based chemicals that have been linked in recent research to better health outcomes.

Vicki Piper, a dietitian at the University of Texas, says that grilling vegetables is one way to take advantage of the nutrients during the summer barbecue season.

"Try a new vegetable every week, one that you have not tried in many years,"” Piper said. "My family favorites are grilled onions, zucchini and asparagus."

To get more out of the change in diet, she says to leave vegetables unpeeled as many of the components are found in their skins.