Red and Yellow and Fast Food Restaurants

Have you ever noticed the phenomenon that so many fast food restaurants have red and/or yellow in their logos? McD's, Pizza Hut, Wendy's, Arby's, Denny's and more. What are your thoughts about this? The article talks about how some butterflies with the orange-red-yellow colouring have that colouring to fend off predators. Could that be an underlying reason for the red and yellow? Or are these colours just catchy? Is there something psychological about them?