to great extent, yes. According to the details given, it can contribute to obesity and high fat gain. When you finished your meal, you gain calories and blood from your brain goes down to your stomach and the digestive system to help digest your food. 650 calories not too much but if you keep on doing this every day, it might be dangerous.
Your brain process slowed down and you 'gain' unconsciousness, therefore you fell asleep. When you sleep, you did nothing and so the calories were stored in your body. Without any workout, you can't burn your calories and if it accumulate, heart diseases, stroke and other health problems might occur, so try to take a walk after finish your meal to burn the calories.
