Food Combining: Does It Work? Nutritionists Give Us the Real Answers

Food combining is a recent trend based on the belief that certain foods pair well and others do not. Although the term “food combining” is somewhat recent, its principles aren’t: The idea that some foods work better with others has been used in Ayurvedic medicine for thousands of years. In the 1920’s, the concept was incorporated into the Hay diet. But this concept has also seen a resurgence in popularity — and when it comes to certain ingredients, that’s for good reason.

Read next: How to Add Turmeric to Your Diet (and Why You Should)

Here, we’ll break down what goes into food combining and why this method of eating has seen a rise in interest lately.  

What are the primary principles of food combining? 

There are a lot of rules when it comes to food combining — and they vary — but there are two primary principles that many agree upon:

• Foods are digested at different speeds. There are fast-digesting foods and slow-digesting foods. Eating them together will disrupt digestion and can negatively impact health. 
• Foods need to be broken down at different pH levels. Ingredients require specific enzymes to break them down, and these enzymes work at varying pH levels. For optimal digestion, you shouldn’t consume foods that will need to be digested at different pH levels.

Is food combining legit? 

Does food combining have any proven value? Maine-based culinary nutritionist Kristy Del Coro, MS, RDN, LDN says that there are some parts of food combining that are valid — but she does feel that the timing doesn’t need to be as strict as some diet plans would have you believe. 

“There are certain combinations, particularly for entirely plant-based eaters, that may be worth paying attention to in order to minimize risk of nutrient deficiencies,” says Del Coro. “Some are fun to know about to enhance or maximize what you get from your foods, but are not absolutely essential.”

California-based nutritionist and founder of Belly2Baby Nutrition, Karlee Rotoly, agrees that certain foods can help unlock others’ nutrients, but finds some flaws in food combining as an overall strategy. “In my opinion, this diet goes against the principles of intuitive eating and encourages the individual to scrutinize everything they consume throughout the day — including water,” Rotloy says. “Any diet or food philosophy that creates strict guidelines about what kinds of foods to eat, particularly when excluding natural foods like sweet fruits, is not one I am in support of. All foods can be enjoyed in moderation.”

The bottom line? Take food combining with a grain of salt and consider the following food combos that do actually work.

The food combinations that definitely work

Turmeric + black pepper

One seriously valuable pair in food combining: turmeric and black pepper. Curcumin, the active polyphenol found in turmeric, has been found to have multiple health benefits, including anti-inflammatory and antibacterial properties. And when consumed with black pepper, turmeric is more easily absorbed by the body — in fact, black pepper has been demonstrated in scientific studies to increase turmeric’s bioavailability by 2000%. So, how does this work? 

“Unfortunately, curcumin is rapidly broken down by the liver and generally poorly absorbed — but that’s where black pepper comes in,” Rotoloy says. “Black pepper contains an active ingredient called piperine that increases the bioavailability of curcumin significantly. It does this by assisting curcumin in passing through the intestinal wall and entering the bloodstream.”

Sodium + potassium

While our bodies need sodium to function, the American diet includes more than enough. In fact, the average American consumes about 3,400mg of sodium a day, which is about 50% more than the Dietary Guidelines for Americans recommends. While health experts often talk about lowering sodium intake to manage or reduce the risk of high blood pressure, Del Coro says it is also important to increase potassium intake. 

“Potassium intake helps offset the negative effects of sodium and plays a role in bone health, kidney health, and cardiovascular health,” Del Coro tells Clean Plates. “Luckily, the latest dietary guidelines require that potassium is labeled on foods so now consumers can actually see how much potassium is in a packaged food. Daily potassium intake should be more than sodium intake, so when reading labels, it’s a good sign if the potassium content is equal or greater than the sodium. But potassium is also increased by eating more minimally processed whole foods (that don’t necessarily contain food labels!).” The takeaway? Look for foods high in potassium, like potatoes, spinach, jackfruit, kiwi, and yogurt (all of which have more potassium than a banana, by the way — although bananas are still a great source of potassium). 

Iron-rich foods + citrus

Plant-based iron-rich foods, like spinach, tofu, lentils, sweet potatoes, and beans, can benefit from being paired with citrus. Rotoly explains that there are two types of dietary iron: heme (from animal sources) and non-heme (from plant sources). Heme iron has a significantly higher bioavailability than non-heme iron. 

“Citrus contains ascorbic acid which increases the body’s ability to absorb specifically non-heme iron,” Rotoly says. “Ascorbic acid does this by creating a bond with the iron molecule in the stomach and assists the iron in entering the small intestine which is where nutrients are absorbed.” Needless to say, this proven combination is especially noteworthy for anyone who follows a plant-based diet.

Vitamin D + calcium

Ever since we were little, the importance of calcium (and drinking your milk) was stressed to us. Calcium is a critical nutrient for heart, muscle, bone, and nerve health. But did you know that your body needs vitamin D to absorb calcium? Without enough vitamin D, you can’t form enough of the hormone calcitriol (aka “active vitamin D”) which results in insufficient calcium absorption. Not to worry, though — vitamin D is relatively easy for the body to get. You can get vitamin D through sunlight, supplements, and diet. Foods highest in vitamin D include mushrooms, especially cremini and portabella, and fish, particularly salmon and swordfish.

Vegetables + healthy fat

It’s no secret that vegetables are typically packed with vitamins and minerals. While some of the vegetables’ vitamins and minerals are easily absorbed by the body, others need a little assistance. Fat-soluble vitamins, like vitamins A, D, E, or K, are better absorbed in the body when combined with some amount of fat. While any fat will improve absorption, Del Coro says it is best to select sources of healthy unsaturated fats, like olive oil, avocado, or nuts and seeds.

Complementary plant-based proteins

When following a plant-based diet, it’s important to consider your protein sources and how they play together. As Del Coro points out, many plant-based sources of protein, including many grains, legumes, nuts, and seeds, do not contain sufficient amounts of all nine essential amino acids to be considered a “complete protein.” 

“The good news is that when these proteins are combined — grains and beans, or grains and seeds — you do get enough of the amino acids you need because the amino acids in these food groups are complementary to each other,” Del Coro explains. “What is lacking in one, is found in higher amounts in the other.” And although experts used to say that these proteins needed to be combined in the same meal, Del Coro says that the new understanding is that they just need to be eaten on the same day. 

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