Listening to music while eating, preferring to eat in front of the TV, getting less sleep... What if we told you that all of these can be unnoticed causes of weight gain? Even whether you eat alone or with a group of friends is important. The time you spend eating also plays a role in the excess calories you take in. Your daily life habits can cause you to gain 450-500 calories a day without realizing it and can mean a 2-pound weight gain in a month.