Has he ever been tested for diabetes or other blood glucose conditions (Syndrome X, hypoglycemia, etc.)? Sounds like high-glycemic carbs may be the culprit. He may find simply choosing foods on the lower half of the Glycemic Index of Foods will help, as well as combining them with the appropriate amounts of fats and proteins.

I've seen my diabetic BIL do this for years after consuming a high-carb. meal without combining protein and fat to slow the uptake of the carbs.

-Grainlady

Here is a link that might be useful: Glycemic Index of Foods

My mom and I used to do this for years. I had to do research myself at the library, as there were no pc's. I came to the conclusion that it was starches and heavy carbohydrates that did it. I think you can do a search on this, some places tell you to eat a food with lots of carbs if you can't sleep at night, and you will go to sleep. With us, it was mexican food, and pasta. Now I never go to sleep after a meal, even on Thanksgiving. I avoid fried foods, and potatoes, pastas, rice, etc. There are plenty of substitues for the starch, like squash and other veggies.
darlene

There is actually a medical reason for this. When we eat blood goes to the stomach area to help with the digestion of the food and can lower the amount of blood going to the brain causing drowsiness.

Just in case you are still following this thread, I've got another possibility for you. Celiac Disease is a grossly underdiagnosed autoimmune disease estimated to affect 1 in 133 Americans. Most people have never heard of this disease. It often causes gastrointestinal symptoms, as well as vague whole body symptoms. October happens to be Celiac awareness month. I'll attach a link to the Mayo clinic. It is highly treatable. (I also had the NEED to fall asleep after high carb meals before I was diagnosed). I hope whatever it is, he finds relief.

Here is a link that might be useful: Mayo Clinic Link