1) You'll eat less.
According to something I once read somewhere, it takes about 20 minutes after you start eating for your "fullness" sensors to work properly. That means that if you finish eating in less than 20 minutes, you have no way of knowing if you ate too much. Ever get super full after the fact? Yeah, that's it. Eat slowly, and listen to your body, not outside cues like the TV or your 1pm meeting. Your body will tell you when you've had enough.
2) You'll have less stress.
Some people think that the "French paradox" (they smoke, drink a lot of wine, eat a lot of triple cream high-fat awesome foods, yet they're thin and have healthy hearts) can be partially explained by how they eat: slowly, around a table, enjoying the experience of a leisurely meal. When you're stressed, your body releases corticosteroids into your bloodstream. These stress hormones do a whole lot of no good to your body, including increasing your appetite (i.e., making you eat more), and increasing blood glucose levels (which, if chronic, can lead to diabetes). Eating slowly promotes less of a stress response during your meal. So relax and enjoy your food.
3) Eating slowly promotes thorough chewing.
One day in college, I did an experiment with a close friend. I asked them to chew some pasta and count the number of chews before swallowing. I did the same. I think I lost 17-3. I didn't realize at the time, but that was another terrible eating habit I had. I now realize that chewing thoroughly is vital to your digestive health. For one thing, it is less taxing on your stomach and intestines, since chewing thoroughly means your stomach and intestines can concentrate on absorbing nutrients instead of first breaking the food down. My guess is that your stomach will produce less acid too (ulcers or heartburn, anyone?). It's really difficult to eat fast and simultaneously thoroughly chew your food. So slow down and chomp down a few more times.
4) Eating slowly causes less of a glycemic response.
I haven't researched this one, but it seems to make sense - if you spread the food that you're eating over a longer period of time, it should cause a less severe spike in your blood glucose levels. These spikes are known to be bad for your health. Also, since you'll probably eat less food if you eat slower, the spike will be even smaller. Double win.
5) Eating slowly can be good for your brain.
Whoa whoa, hold on a second. Where'd this one come from? Well, eating slowly allows you to enjoy your food and all the amazing sensations contained therein: colors, textures, smells, flavors, even sounds. Exposing your senses to new experiences has been known to stimulate the brain and keep it healthy as you age. And focusing your attention, or mindfulness, on the sensations associated with your food can be meditative. Eating slowly also allows you to take a break from the stresses of the day, which can both boost productivity and promote greater creativity.
So there you have it, folks. Five reasons why eating slowly is good for your health. On the downside, I am now the slowest eater in my family and on my team by far. But at least I'm enjoying my food!
Eat slowly, live longer.
Disclaimer: Don't take nutrition advice from engineers.
Edit: After writing this post, I googled "eating slowly", and the first result was this other post titled "5 Powerful Reasons to Eat Slower". Credit where credit is due! http://zenhabits.net/2007/07/5-powerful-reasons-to-eat-slower/. I really didn't read that post until after writing this one, though. Looks like they share some of the same thoughts. Guess I'm not crazy after all. =)