Jane Says: The 'Food Combining' Diet—Fact, Fiction, or Something In Between?

Our food advice columnist is dubious that separating proteins and carbohydrates improves digestion.
Sep 26, 2012· 2 MIN READ
Jane Lear is a regular contributor to TakePart and the executive editor of CURED, a magazine devoted to the art and craft of food preservation. She was on staff at 'Gourmet' for almost 20 years.

“I’ve heard a lot recently about food combining. What are the rules and where should a novice go to learn more?” —Karyn Stanley

There are a number of historical precedents that outlaw the combination of certain foods—an Ayurvedic diet and Jewish kashrut laws, being two notable examples. But what we tend to think of as food combining has its roots in a health philosophy of the 1800s subsequently called Natural Hygiene. It centers around the belief that eating inappropriate combinations of certain foods wreak havoc on the digestive system, leading to all manner of ailments.

Fast forward to the 1980s (I know, still ancient history). Following on the heels of Judy Mazel and The Beverly Hills Diet, Harvey and Marilyn Diamond brilliantly repositioned Natural Hygiene for a whole new crowd in their 1985 manifesto Fit for Life. Appearances on The Merv Griffin Show helped catapult the book to mainstream fame. In truth, you can’t fault the book’s emphasis on eating complex carbohydrates such as vegetables, fruits, and grains rather than meats—that’s no-brainer advice these days.

But nutritionists, doctors, and scientists both then and now have dug in their heels when faced with the primary tenet of the book, which is to never eat alkaline foods like fruits, vegetables, and grains with acidic foods—meat, poultry, fish, and beans. (You can kiss a restaurant meal goodbye.) Nor should you interfere with your body’s elimination process by eating anything except fruit or juice for breakfast. Yep—that means no bowl of steel-cut oats or fragrant miso soup, let alone a fried-egg sammie or sausage biscuit.

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The food-combining theory has a number of variations, but in general, proponents do not consume proteins and carbohydrates in the same meal. The reasoning is as follows: Since protein digestion utilizes enzymes that are more acidic than the ones utilized by carbs, when you eat those two types of foods at once, the enzymes cancel each other out, thus the food can’t be assimilated. Instead, it sits in your system and rots or ferments, building up as toxic material in your colon. Eeew.

This idea may have seemed imminently logical in the 19th century, when the chemistry of food and human physiology were imperfectly understood. But for decades, scientists have had a pretty good grasp on this stuff, and have refuted the claims.

Everything you eat, after all, travels through your digestive system. The first stop, the stomach, is basically an acid bath (which kills bacteria and pathogens and begins to break down proteins). Carbs spend time in that acidic environment, just like proteins do (although not as long). The major part of digestion and absorption happens in the small intestine, or duodenum, which produces the different enzymes that digest carbs, proteins, and fats. All of those enzymes are released, no matter what food is in the small intestine. Any undigested food is passed from the small intestine into the large intestine and eliminated from the body as waste. Amazing, when you think about it.

Another point: Proponents of food combining maintain that fruit should always be eaten by itself. But the definition of the word fruit may surprise you. Botanically, a fruit is a part of a flowering plant that contains seeds, even though culinarily, it may be used as a vegetable. Examples of fruits treated as vegetables include tomatoes, squashes, peas, beans, and bell peppers. The plot thickens, in other words.

It is also important—critical, in fact—to understand that proteins and carbohydrates are not foods. They are nutrients. (The loss of this distinction is one of Marion Nestle’s pet peeves.) You will find both protein and carbs in many foods. Grains, for instance, are actually a valuable source of protein, especially for vegetarians. Potatoes and pasta contain protein, as do lots of vegetables...and breast milk. In fact, the human digestive system is beautifully engineered for the simultaneous digestion of protein and carbs.

All this aside, some people find certain food combinations distasteful from a cultural point of view or difficult to digest easily. That is fair enough; everyone is different, after all. But I, for one, am not giving up my steel-cut oats, let alone the occasional sausage biscuit, for breakfast.