There are almost as many ideas about what constitutes healthy food as there are commentators on the subject. Though some of their ideas are contradictory, all are expressed with righteous fervour. Because food combining is supportive of every diet, we have chosen not to recommend any specific form of the dietary regime. If the food is combined well, and the acid-base balance is not disturbed, we can count on efficient digestion of the nutrients. If put together inan inappropriate combination of foods, it may remain undigested in the body and degrade there.

Rules for Combining Foods

The concept of food combining proposes that the way our bodies digest specific foods should guide our eating approach. Proper food combining is believed to enhance digestion and nutrient assimilation. Various sources may present slightly different rules for food combining, but the most common principles include:

  • Eating fruits on an empty stomach, especially melons
  • Avoiding the combination of starches and proteins
  • Avoiding the combination of starches with acidic foods
  • Avoiding the combination of different types of protein
  • Avoid combining protein with fat, consuming sugar only on its own, and separating fruits and vegetables when eaten.

The underlying premise of food combining is that our bodies can only effectively digest one concentrated food at a time. Food combining considers certain food categories that combine well with specific others. The alignment of the body’s digestive conditions with the specific foods consumed helps in improving digestion and overall health.

Bad Combinations 

Combining Protein and Starch 

The combination of protein and starch, such as bread and cheese, meat and potatoes, chicken and rice, and peanut butter sandwiches, is widely recognized as a suboptimal pairing. These food combinations are frequently found in industrially processed foods, which commonly include meat and meat products, fish, cheese, bread, cereals, and potatoes. Starch, being a complex carbohydrate, necessitates the action of specific enzymes to break it down into simpler sugars. The digestion of starch requires alkaline conditions, while protein digestion thrives in an acidic environment. Combining starches and proteins in a single meal may require the digestive system to operate in both alkaline and acidic states simultaneously, which can lead to disruptions in the digestion of all consumed foods. The presence of protein in the gastric environment has the potential to hinder the digestion of starch due to the potential interference of acid and enzymes required for protein breakdown with the enzymes essential for starch digestion. Consequently, this interference can lead to delays in the digestive process and nutrient absorption, resulting in discomfort characterized by symptoms like bloating or gas. However, this issue can be effectively mitigated by avoiding the simultaneous consumption of high-protein foods and starch-rich foods.

Combining Fat and Sugar 

Nut spreads, chocolate, sweetened whipped cream, ice cream, nougat, olives with bananas, avocado with sweet fruits, nuts and sweet fruits, cheese and jam are all examples of fat-sugar combinations. The combination of fat and sugar in a dietary context is known to be unfavourable for the process of digestion. Sugar is easy to digest. Industrial sugars (disaccharides) are broken down into monosaccharides and absorbed into the bloodstream fairly rapidly. But when we eat sugar together with high-fat food, the sugar is mixed with the fat which inhibits the kneading movement of the stomach wall. Sugar that is completely surrounded by fat cannot make contact with the gastric juice. It is not stabilized and quickly begins to ferment. A diet high in both fat and sugar can lead to obesity, insulin resistance, and inflammation, all of which are risk factors for chronic diseases such as type 2 diabetes, heart disease, and some cancers.

Combining Starch and Sugar 

Notable examples include honey cakes, raisin bread, custard tarts, doughnuts, and other indulgent treats, all of which can adversely affect digestion. The widespread enjoyment of these beloved sweet foods directly contributes to the prevalence of obesity observed among a significant portion of the populations in advanced countries. The key lies in the relative quantities of these nutrients. Combining starch and sugar involves juxtaposing two prominent nutrients that undergo distinct digestion processes, leading to the mixing of disparate digestive pathways. When we eat food rich in sugar (like a spoonful of honey, a ripe banana, or a lump of sugar), digestion takes place quite fast as the breaking down of disaccharides to become monosaccharides happens smoothly and effortlessly. The digestion of food rich in starch takes place slowly, mainly because of the presence of protein and fat. With starch and sugar in one meal, or even one dish, we run the risk that part of the sugar will end up in the fermentation zone of the stomach, in the middle, away from the gastric juice, and will begin to ferment. Slow and incomplete digestion lead to the presence of undigested disaccharides and starch residues in the chyme within the intestines, where further fermentation takes place, inevitably resulting in intestinal bloating.

Combining Starch and Acid 

The combination of bread or potatoes and acidic fruits or vegetables, yoghurt, buttermilk, soft drinks, coffee, and alcoholic beverages, including wines, beers, and spirits, are examples of foods with high starch content and high acidity.

Generally, starch necessitates an alkaline environment for its breakdown into glucose molecules during the process of digestion, while acid requires an acidic environment for optimal digestion.

The initial breakdown of starch occurs in the oral cavity due to the presence of the salivary enzyme ptyalin, which functions within a mildly acidic range (pH 5.5-7). When we consume foods with an acidity level surpassing 5.5, the saliva becomes excessively acidic, rendering ptyalin ineffective. The same outcome occurs when we ingest acidic beverages alongside a meal, as they also mix with saliva in the oral cavity. If the starch is not predigested, digestion has to start in the duodenum, under the auspices of the pancreas. It is a heavy burden for the pancreas, and there remains a risk that part of the starch will not be broken down and that sugar residues will undergo fermentation in the intestine, causing intestinal bloating and flatulence. However, the impact of combining starch and acid on health can be influenced by the specific types and quantities of starch and acid consumed.

Combining Protein and Acid 

Examples of protein-acid combinations include meat with vegetables that contain lactic acid, rice with curry sauce, chicken with pineapple, cheese with mustard frankfurter/sausage with sauerkraut, herring pickled in vinegar fish and cocktail onions pickled in vinegar. The combination of protein and acid in the context of digestion can have adverse effects on health.

The presence of acids, such as in highly acidic foods, can interfere with the digestion of protein in the stomach. The digestion of protein initiates in the stomach with the enzyme pepsin, operating in an acidic environment (pH 2-4). The process continues in the duodenum, where trypsin and chymotrypsin enzymes function in a more alkaline setting. However, the presence of acids hinders the secretion of gastric juice, impeding protein digestion in the stomach. Highly acidic foods can maintain excessive acidity, inhibiting pepsin function and reducing gastric juice secretion. Consequently, protein digestion remains incomplete, leading to the potential degradation of protein residues in the stomach and an unpleasant taste. This incomplete digestion further hampers protein breakdown in the duodenum, with ongoing protein degradation in the intestines. 

The combination of high-protein foods and mildly acidic foods has minimal impact on the stomach. Compared to the combination of starch and acid, the combination of protein and acid is less harmful. The presence and quantity of acid also play a significant role.

Combining Protein and Sugar 

The combination of protein and sugar is generally unfavourable, but it is not commonly encountered. High-protein foods typically have low carbohydrate content. Among meats, only non-muscular tissue, such as internal organs, contains minimal amounts of carbohydrates in the form of glycogen. In plant-based foods like nuts, seeds, and pits, the carbohydrate proportion is also very small, although there are exceptions such as cashew nuts, lupin seeds, pine nuts, sesame seeds, and leguminous vegetables. 

High-protein food on the other hand always contains a lot of fat. In this sense, the fat-sugar combination and the protein-sugar combination overlap to an extent. If we add sugar to high-fat food, we are most likely to arrive at a bad protein-sugar combination as well. Examples of protein-sugar combinations include meat with sweet sauces, fish with fruit, meat with apple sauce, and consuming a sweet dessert following a protein-rich meal. 

High-protein meals tend to remain in the stomach for an extended period and are challenging to digest. When a well-filled stomach contains sugar, it is not rapidly digested, potentially leading to fermentation.