The reason I ask is because it takes at least 20 minutes for your stomach to send the proper signals to your brain that it's full. This can be a big problem for a chronically speedy eater because it leaves a window of time for over eating. This over eating can lead to uncomfortable digestion, unwanted weight gain and depending on the person's health; increased blood sugars or cholesterol.
We all over eat on occasion and there are many reasons for it, but for some people eating fast can be a daily issue. These habits often develop early in childhood and be very hard to break. The best way to slow down though is to become more mindful of what you are doing. A couple of things you can try include:
1) Pacing yourself off the slowest eater at the table.
2) Pre-portion your first plate to what you think is an appropriate amount of food and then tell yourself you cannot go for seconds until 20 minutes has passed. (Give your stomach that time to send the signals it needs to!)
3) Set down your fork between bites or drink water between bites.
4) Make sure you eat at regular times through the day and don't go longer than 6 hours without eating too avoid becoming too hungry.
5) Avoid watching TV or working on a computer while eating. Eating while distracted makes it almost impossible to monitor your intake and over eating or eating too quickly is much more likely.
6) Try using tools to help you slow down or reduce your portions like smaller plates or the smart fork. Even just using smaller cutlery will mean your will have to take smaller bites.
Fast eating is not a habit that you can change over night and will require you to work on being mindful of your eating on a regular basis. The good new is that with regular practice your can change your eating habits.