Food combining describes how mixing different types of food in one meal supports or stresses digestion. It has practical recommendations to improve digestion. Good digestion means feeling well, having energy and being slim while needing less food. A bad digestion can cause illnesses. Food combining is not a diet because it doesn’t prescribe types of food or quantities. (People do turn it into a diet however; the Hay diet is related.)

Interesting thought
The book I read about food combining starts with a discussion that our body is not designed for lots of foods we currently eat. This includes many agricultural products such as grains. People eat them because they are so practical in building a complex society (=cheap to produce) but they need to be processed before the body has a chance of extracting nutrients. Herbs and spices improve digestion but problems such as obesity, bloating and acid reflux remain and are accepted as normal.

Fortunately just paying some attention to how digestion works solves most of the problems while not having to change diet. Food combining doesn’t say “eat berries”

Scientific basis
The scientific basis for this is not clear to me (Wikipedia is currently biased). Many ideas sound very reasonable however and like many people I feel improvements. Use your own judgement. It’s easy to try: just keep on eating what you currently eat but change the timing.

Basic principles
There are two main ideas underlying food combining: dominant nutrients and acid-base balance.

The enzymes that digest nutrients like proteins and starch work best in different (acidic) conditions. According to food combining the body creates those different conditions depending on the dominant nutrient in the food being digested. Usually that’s the nutrient that’s most abundant. If for instance both proteins and starch are abundant this implies that it’s not possible to create the optimal conditions for both and digestion suffers. Some combinations are compatible while others conflict.

Acid-base balance is about balancing concentrated food (nuts, grains, most protein sources) with less concentrated food (vegetables, anything with a lot of water in it). Since I can’t find supportive information about it and I don’t see how it’s so important you’ll have to read elsewhere if you want to know more hehe.

Practical recommendations

• Most natural foods have a dominant nutrient. Eating only one food item at a time and waiting before the stomach is finished is always a good combination. (Legumes are an exception because they contain a lot of proteins and starch at the same time. That explains why they are inherently hard to digest. Tofu is an exception.)
• Sour food and starch don’t combine well because the sour inhibits amylase in the mouth. So no sour drinks, fruits or sauces when eating potatoes, pasta or rice.
• Eat fruits before the meal, not after it. They are processed faster than other food and their sour can conflict with the digestion of other nutrients.
• Don’t eat significant quantities of proteins and starch in the same meal (yes, this is very common).
• Don’t eat too much at a time. Smaller quantities are processed more efficiently.
• Use your own judgement and don’t go too far. Eating should be fun as well (my recommendation).

More information
Related books are The New Book of Food Combining (with recipes) (Amazon USA, DE), the Food Combining Bible (Amazon USA, DE) and Handboek voeding en gezondheid (Bol.com). These books are by Jan Dries. Other books tend to be more pretentious.