You're Accustomed to Overeating
One of the major reasons a person might over eat is because they have become accustomed to it. Some people simply over eat out of habit. Thankfully habits can be broken and changed and scientifically it takes only 30 days to break them. Therefore, start forming some new and healthy eating habits.
You're Unaware of Your Calorie Intake
Many people are not aware that they are consuming more calories than they burn and as a result over eat. Being aware of your food's caloric content is one of the most effective ways to curb over eating and make your exercise attempts effective. In addition, it also helps you maintain a healthy eating lifestyle.
You Find Food Comforting
Often times, people eat not because they are hungry but to comfort themselves or make themselves feel better when tired, depressed etc. It's important you try to avoid this as much as possible because it inevitably leads to over eating. Rather than eating a myriad of sweet and sugary foods to make yourself feel better, exercise or hang out with family or friends for comfort. These two actions help to significantly increase your mood as much as indulging in sweet sugary foods.
You Eat Too Fast
Slow down when eating. It takes about 20 minutes for the digestive system to report to the brain that you're full and eating with lighting speed doesn't help this process. Eating fast does not allow your brain react to the satiety signal coming from your body, and this leads you to believe you are still hungry when your body just needs some time to tell your brain that you are full.
You Snack Frequently
If you want to eat, eat real food. Try to avoid snacking and if you must snack, make sure you are physically hungry and that you ready to forfeit eating actual food for the snack (but ensure this isn't done often). A lot of people tend to snack when they are not hungry or worse right after meals. Try to avoid the habit of eating snacks right after meals. Snacking in the absence of hunger can cause just as much weight gain as consuming high calorie foods or oversized portions.