Food Combining: Improve Digestion & Nutrient Absorption

Many meals consist of multiple organic foods, or those considered “healthy,” but if that combination is incompatible, symptoms of discomfort can arise shortly after eating. Acidity, stomach pain, fatigue, and indigestion are some of the most common warning signs the body emits. Another consequence that appears “in the shadows” is the poor assimilation of the nutrients and compounds ingested. The art of food compatibility is not simple.

Although the topic hasn’t received much attention recently, the theory underlying the correct combination of foods isn’t new: it originated in the 20th century during the hygiene movement. The creator was physicist William Howard Hay, though it was Dr. Herbert M. Shelton, a naturopath, who popularized it with the publication of his book, Combining Foods Simply.

As he explains in his work, when digestive functions are delayed or temporarily suspended by inappropriate food combinations, the conversion of these foods into vital nutrients (amino acids, vitamins, minerals) does not occur, and toxins are produced that force the organs of elimination to work harder and overload the intercellular medium, leading to undesirable symptoms.

A very similar theory is repeated in Ayurveda, where Viruddha Ahara (incompatible foods) is discussed, explains María Alejandra Avcharian, an Ayurvedic therapist trained in India, international speaker, and creator of Modern Ayurveda.

“It’s not simply about ‘this doesn’t go with that,’ it’s a much deeper look at how the qualities of foods interact within the body,” she elaborates. In this Eastern current, each food has an energy, a temperature, a digestive effect, and also a mental impact. “When we combine elements that require opposite processes, the system becomes overloaded, the digestive fire weakens, and ama is generated, which is the residue the body cannot fully transform.”

Food compatibility does not encourage prohibitive, fearful, or obsessive behaviors about what you eat, comments Matías Marchetti, a nutritionist and author of books on healthy living. For him, it’s essential to understand that the constant interaction of foods in the stomach makes it impossible to avoid some percentage of nutrient absorption loss. “Sometimes these percentages are minimal,” he adds.

Ayurveda, for example, doesn’t seek to eat with fear, but with awareness, explains Avcharian. The same is repeated by healthcare professionals from various disciplines who, like her, Marchetti, and a vast academic body of evidence, recognize some of the less favorable food interactions for digestion and nutrition. Below is a list of them:

1. Two Types of Concentrated Proteins in the Same Meal

These are heavy foods and, complex to digest. In his book, Shelton explains that the acidity, type, timing, and intensity of the secretions of different proteins are not uniform. It logically follows that the body finds it difficult to digest multiple proteins at once.

“Do not combine nuts with cheese, nor any of the following foods with concentrated protein: nuts, avocado, soy, cheese, eggs, meats,” suggests the author in the book. He also adds that alfalfa sprouts, considered a green vegetable, are a great accompaniment to a concentrated protein.

2. Alcohol with Foods Rich in Fats

According to Marchetti, on the one hand, alcohol increases intestinal permeability—the selective capacity of the intestinal wall to allow nutrients to pass through and block toxins, bacteria, and viruses—while fat delays gastric emptying—the process by which the stomach releases its contents into the small intestine—which can cause digestive discomfort.

“It’s not a critical nutritional interaction, but We see digestive,” he assures.

3. Cold Foods with Hot Foods

Habits such as drinking cold beverages while eating a hot dish or finishing with a very cold dessert immediately after something freshly baked can be harmful.

Avcharian explains that the recommendation is due to the fact that both types of foods have different digestion times and processes. “When foods with different temperatures are mixed, digestion slows down and fermentation, gas, inflammation, or accumulation of ama can occur,” she says.

4. Sources of Tannins, Calcium, and Phytates with Iron-Rich Foods

The World Health Organization reports that the absorption of iron—especially non-heme iron (of plant origin)—can be drastically reduced by certain compounds found in foods and beverages.

Among the main inhibitors, the institution mentions phytates (present in cereals, grains, wholemeal flours, bran, nuts, and legumes), tannins (infusions such as tea, coffee, mate, cocoa), and calcium (present in milk and dairy products such as yogurt and cheeses).

5. Fruits, Best Eaten Alone

It’s common to accompany them with yogurt, granola, or nuts. or to follow them with infusions such as morning coffee or tea; however, Ayurvedic medicine considers that, due to how quickly they digest, they should be consumed without accompaniment.

“If we mix them with heavier foods, their transit slows down and they can cause fermentation and bloating,” explains Avcharian. The classic recommendation, she adds, is to consume them alone or a while before meals.

The concept of food combining, rooted in traditions like Ayurveda and gaining traction in modern nutritional approaches, suggests that mindful consideration of how foods interact during digestion can contribute to improved well-being. While more research is needed to fully understand the extent of these interactions, paying attention to how different foods are paired may offer benefits for those seeking to optimize their digestive health.