Half of all Americans suffer from some kind of digestive problem, such as excess gas, heartburn, diarrhea, and worse. Diet seems to play the key role in this, of course, but what role it plays may surprise you.

Studies have shown that gastric problems are just as common amongst vegans as they are amongst omnivores in the human population. About the only eating group that is more likely to have digestive worries are those that eat mostly junk food.

Most Americans, even the more nutritionally informed, are under the impression that foods can be mixed almost at will without ill effects. It's all about their nutritive content and how you get that content can be in any order you wish.

That's not exactly true.

Of course, we all know that mixing dairy products with citric fruits like pineapple is probably going to lead to stomach aches. Most of us understand the idea that putting salsa on our breakfast cereal is probably a bad plan.

The two most common gastric problems people have are indigestion and irritable bowel syndrome. Both of these are directly related to nutrition and how we manage our nutritional intake. Just two generations ago, our food intake was much different than it is today. Four generations ago, it was unrecognizable compared to what we have now.

Back-tracking to a time when America didn't really have grocery stores as we know them now, when food selection was based purely on what was available within 50 miles or so at that time of year. While the resources were much more limited than they are today, they did have one big thing going for them that we no longer have now.

Nearly all of those foods were naturally complementary. Foods that appear for harvest at about the same time of year and grow in the same climactic regions are nearly always complementary. Thus, people in those days, while they had fewer nutritional choices, had automatic complementary choices. Not so today.

Obviously, I don't think we should trade what we have now for what they had then, but it was nice not to have to think about it. Now, of course, we do.

The basic idea of modern food combination theory was created by Dr. William Hay. Finding research from varied sources that showed different connections between nutritional types (carbohydrates, sugars, etc.) and resulting problems, Dr. Hay worked out a system for combining foods. He used it to cure his own high blood pressure and early-onset diabetes.

In the second half of this article series, we'll look at Dr. Hay's combinations and what further research has found since his initial discoveries.

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