Food-combining is extremely important issue to take note of when suffering from chronic digestive disorders. The basic idea behind food combining is that different parts of the digestive tract attend to the digestion of different classes of macronutrients and foods. Carbohydrates such as bread, potatoes and oatmeal undergo preliminary digestion in the mouth with the secretion of salivary amylase, and by mechanical digestion (chewing). Carbohydrates then pass through the stomach unaffected by the secretion of gastric juices, and then on to the small intestine where the secretion of pancreatic enzymes finish the job of carbohydrate digestion. Proteins undergo no digestion in the mouth, other than mechanical digestion by chewing, and then pass into the stomach where they are then acted upon by the powerful gastric juices than contain hydrochloric acid and pepsin. The acid and enzymes secreted by the stomach help to break down large chains of proteins in smaller peptide chains. These peptides then undergo further digestion by pancreatic enzymes into amino acids in the small intestine, where they are absorbed across the intestinal wall. Fats undergo digestion only once they reach the small intestine, where bile salts are released by the liver and gall bladder to emulsify these fats, which are then acted upon by pancreatic enzymes.

Digestion is an obviously complicated process, and one that we rarely pay much attention to unless it gives us trouble. Examining how these different classes of foods are digested in different parts of the digestive tract we can see that combining these foods may affect adversely affect the process of digestion. The biggest problem I see in my practice is the combination of carbohydrates and proteins in the diet, such as meat and potatoes, which in large part require different mediums in order to be digested properly. Enzymes that break down carbohydrates require an alkaline medium, whereas proteins require an acid medium. When carbohydrates are consumed with proteins they inhibit the secretion of stomach acid and enzymes, or inhibit the ability of these stomach juices to properly act upon the proteins, which are mixed up with carbohydrate. In some people this may delay stomach empyting, and as a result, bacteria in the stomach begin to ferment the carbohydrates, releasing gases in the process. This leads to stomach bloating, burping, nausea and heartburn, causing the stomach and esophagus to become distended. If this becomes a chronic event, it may cause the serosal membrane of the stomach to adhere to other tissues in the abdomen, such as the diaphragm, leading to hiatus hernia. Or, poor gastric motility and bloating may compromise the function of the lower esophageal sphincter, allowing stomach juices to rise up into the esophagus to promote heart burn.

The other event that may occur is that proteins undergo little digestion in the stomach because carbohydrates impair this process, and instead pass through into the small intestine largely undigested. The enzymes released by the pancreas cannot break these proteins down properly, and once again specialized bacteria act on these improperly digested proteins and putrify them. Unfortunately these bacteria release toxic metabolites in the process that damage the intestinal wall and enter into the blood and tax the detoxification systems of the body. In many cases we see clinical symptoms of both events: carbohydrate fermentation in the stomach, and protein putrefaction in the intestine. Both these events place undue stress upon the digestive tract, and set the stage for chronic insult that leads to epithelial damage, compromise the integrity of the gut wall, and leads to intestinal permeability syndrome. Patients with any chronic digestive disorder, as well as those with autoimmune diseases such as multiple sclerosis or rheumatoid arthritis, should follow the basic tenets of food combining, described below.

Animal proteins should NOT be eaten with carbohydrates, whether they are starchy foods like rice, pasta or potatoes, or sweeter foods like fruits or sweeteners. Similarly, fruits and desserts should be avoided after meals, especially protein-rich meals. The simple carbohydrates undergo rapid digestion, and even eating them after complex-carbohydrates can impair digestion and promote fermentation. Most non-starchy vegetables such as broccoli, chard, celery and asparagus can be eaten with proteins or carbohydrates, as they do not impair the digestion of either. Some foods like dairy, which are a complete food, should be eaten alone, without combining other foods.