Mice fed ad libitum eat most food at night and gain weight, become diabetic, have high plasma fatty acids, and are prone to heart disease.

“When we give mice ad libitum access to food, they can eat anytime, then they will eat nearly 85% of the food during nighttime when they're awake, 15% to 30% of food during daytime when they typically sleep. And in this lifestyle, the mice will slowly gain weight. They will slowly become diabetic, they will have high plasma fatty acids that will make them prone to heart diseases, and many other bad things will happen.”