So says a report in the New York Times: Midnight Meals – New York Times

“Eating a big meal just before going to bed has been found in studies to elevate triglyceride levels in the blood for a period of time,” Dr. Aronne said. A higher triglyceride level “has been associated with metabolic syndrome and insulin resistance,” both related to weight gain, he said.
Dr. Aronne suggested a theoretical framework for why late meals may stay with you. “If you ate 500 calories during the day but walked around afterward, your muscles would be competing with your fat cells for the calories and could burn them up as energy for physical activity,” he said. “But if you consume it at bedtime, with no physical activity, the body has no choice but to store the calories away as fat.”