HOUSTON (AP) — Snack and soda makers that often are blamed for fueling the nation’s obesity rates also play a role in educating the dietitians who advise Americans on healthy eating.

Plano, Texas-based Frito-Lay, Kellogg, along with Coca-Cola and others, are essentially teaching the teachers. Their workshops and online classes for the nation’s dietitians are part of a behind-the-scenes effort to burnish the images of their snacks and drinks.