This week's "What's Ailing You" report looks at fad diets.

The diets often promise fast results. Registered dietitian Jill Castle says it bothers her when fad diets eliminate a specific type of food or an entire food group.

She says you're better off designing a diet around the foods you like. Castle says to fill a quarter of your plate with meats like chicken and turkey, a quarter with whole grains, and half with fruits and veggies. She says it's important to eat food from all of the food groups to feel satisfied.

"Find things that work for you, you can sustain, things you can live with for the next 10 years, not the next 10 days," says Castle.