I am looking at getting a 6 pack backpack for college fall semester due to a full schedule which won't allow me enough time to go out and eat or go home in the day. I'd rather prepare all my meals in the morning and bring them with me to eat throughout the day, even in class. Does anyone own a six pack bag and if so whats your review on them and how long can you keep meals in them without the temperature rising? Any info would be appreciated