It will all start with acid reflux, or sometimes called GERD or stomach acidity. After you eat, digestive enzymes and acids are released in your stomach to break down food further and get the nutrients and separate wastes. But because you're tired and a full stomach makes you terribly sleepy, you lay down just a few minutes after supper. So, instead of keeping all that food down in your stomach you spread it a bit around along with the acids that often find their way back to your esophagus. Thus, the "reflux" which is dangerous.
It's important to keep upright after meals, especially supper. It helps good digestion and promotes normal body functions associated with digestion. So I always keep standing up or sitting erect after meals, or better yet, walking slowly and leisurely around for a while to prevent my tummy from bulging or adding on excess weight in the wrong places.
But the best thing is to never eat tons of food during supper. The ideal thing is to eat light supper at 6 pm and get to bed at 9 pm. Experts say the digestive system settles down to rest after about 3 hours of digesting food. But the problem is, you get home from work late because of overtime, meetings, and traffic. So what should you do? Do what I did when I still had a job before I went full-time blogging Choy's Cuts and other sites. I ate some healthy snacks on my way home and ate just enough at our dinner table.
I got home at 7, ate supper, chat happily with my wife as I walked a bit around, and went to bed at 10. Anyway, my advantage was that, my work the next day started at 1 pm. So sometimes I could extend my bedtime to start at 11 pm.
It helps to have heavy, healthy breakfast daily plus a heavy lunch, minus the in-between snacks. Then eat light at 5 pm while you're on your way home (don't starve yourself and later eat a lot come dinner time) so that you eat less at home. And exercise regularly.
Now, what happens if you mindlessly eat tons during late dinners and then sleep right away so that you develop acid reflux? From acid reflux comes heartburn that feels like a heart attack (and one that can up your blood pressure), indigestion, weight gain, stomach bulge, coughing that doctors sometimes get baffled about, not knowing it's cause, hoarseness, asthma, and even cancer (cancers thrive in acidic environment). A word about heartburn--it can create a lot of ugly sensations that make you think you're dying.
What should you do if you already have reflux? The remedy is really simple. Drink alkaline water regularly. Avoid getting a full stomach after eating. Exercise regularly, don't drink water while eating or right after eating, and eat and sleep on time. Plus, zero vices. Of course, never forget consulting your medical doctor about it.
Finally, about "midnight snacks"? Avoid it at all costs.