Another aspect of choosing the right foods, is the information in the book "Eat Right For Your Blood Type". (go through the search box on the books page and you'll be directed to this book).
While it seems to many as an overwhelming micro-management of one's diet, it presents a strong case for the best digestion and assimilation of proteins, grains, and other foods that affect muscle strength, cardio-vascular capabilities and effective digestion.
The site
http://www.4yourtype.com provides some insights into this diet management system. You can even order a home blood test to determine your blood type.
If you feel too full, sleepy, or full too long, after eating a healthy meal, consider at least getting this book from the library and learning about this topic. It is good for the whole family.