Are you considering going on the ketogenic diet? Before you start filling your shopping cart with grass-fed butter and bacon, know this: While you've likely heard about this high-fat, very low carbohydrate diet - and you probably even have a friend or two who have tried it - there's still a lot of confusion about what it really takes to follow keto.

"In general, people say they're on the ketogenic diet, but it's not actually the case - a lot of times they're just doing a low-carb plan," says Ginger Hultin, RDN, a spokesperson for the Academy of Nutrition and Dietetics and a Seattle-based dietitian.

The reason for this, says Hultin, is that the diet itself is challenging to follow. "Because 80 percent or more of your calories must come from fat, if you're doing the diet correctly, you need to be calculating, weighing, and measuring what you're eating," she says.