Find out what foods you can eat together to optimize nutrient absorption plus the ones you should avoid combining.

Jessica Ball, M.S., R.D.
Updated October 03, 2019

It can be hard to keep track of all of the most trending fad diets, as they usually leave the spotlight as quickly as they come in to it. One of the newest trends is food combining for optimal digestion. But exactly what is food combining all about? Here we'll dig into what food combining is and what you should and shouldn't believe about this diet trend.

What is Food Combining?

The recent trend of food combining looks at the specific types of foods you should be eating together to improve digestion and health, plus the combinations to avoid to prevent digestive issues. Research shows that certain food combinations can have nutritional benefits when eaten together, like how rice and beans together deliver a complete protein source (which is especially important for vegans or vegetarians), while other combos can make it harder to absorb nutrients, like how having tea with iron-rich foods can decrease iron absorption (which is important to know if you're trying to increase your intake of iron rich foods to combat low iron levels).

Getty Images / Tamara Staples

But contrary to what this new diet trend suggests, there is no scientific evidence supporting food combinations that improve our digestion. And in fact, many of the principles of food combining outlined in this trend actually contradict what we know to be true about digestion.

The food combining diet suggests that fruits, protein, starches and nuts or seeds should not be consumed together and that you must wait 3 to 4 hours after a meal before introducing a different food group. The rationale is that those foods do not optimally digest when eaten in combination and can impact the acid balance of our body. But the truth is that our digestive system is very efficient at obtaining nutrients from food and not as sensitive as the people promoting the food combination diet perceive it to be.

Regardless of the combination of foods we eat, enzymes that break down protein, fats and carbs are always secreted when those foods are present. And eating foods cannot change the pH of your body in any significant way. This is a result of a phenomenon called homeostasis, which refers to the numerous safeguards that allow our bodies to involuntarily stay at equilibrium. No matter the combination of foods or the time between meals, our gut is doing its job.

The Healthy Food Combinations to Actually Try

Overall, the most effective way meet your nutrition needs is to eat a variety of foods from every food group. But if you are looking to get more of one or more nutrients from certain foods, these food combinations can actually help. Read more about these nutrition-boosting combinations and try some of the tasty food combining recipes.

Pictured: Herbed Tomato Gratin

Vegetables & Healthy Fat

Several vegetables contain vitamins that are fat-soluble, meaning they need some sort of fat source to be absorbed. Orange vegetables with vitamin A, like carrots, and green vegetables with vitamin K are good examples. Tomatoes also fall into this category. They have a chemical called lycopene that is absorbed better when consumed with a healthy fat. For this reason, enjoy your Balsamic Roasted Carrots or your Caprese Salad with Heirloom Tomatoes & Burrata prepared with olive oil.

Pictured: Turmeric-Roasted Cauliflower

Pepper & Turmeric

Turmeric is a nutritional powerhouse on its own, but black pepper gives it an unexpected boost. This colorful tuber has a powerful anti-inflammatory compound called curcumin that helps our body stave off chronic disease, like arthritis, anxiety, and heart disease. Black pepper, on the other hand, contains the compound piperine, which increases how much curcumin our body can absorb by 2000%. Our delicious dinner side of Turmeric-Roasted Cauliflower delivers a healthy dose of turmeric and black better sprinkle.

Pictured: Broccoli Salad with Bacon

Broccoli & Mustard

Raw broccoli is a good source of the powerful cancer-fighting compound sulforaphane. But cooking destroys the enzyme (myrosinase) in broccoli that makes sulforaphane available to your body. The fix? Combine broccoli with mustard (yes, the condiment) or another raw cruciferous veggie, such as wasabi or arugula—the extra dose of myrosinase will help you absorb more sulforaphane, as studies have shown.

Pictured: Snap Pea & Cherry Tomato Stir Fry

Tomatoes & Soy

For people with prostate cancer or a family history of prostate cancer, this combination may help. There have been several studies looking into how tomatoes and soy can help combat prostate cancer from advancing. A recent clinical trial in The Journal of Nutrition reported that it is likely due to the lycopene in tomatoes interacting with the isoflavones in soy, both of which are antioxidant compounds. There are many ways to enjoy this powerful combination at home, including our Sauteed Chicken and Edamame Salad with cherry tomatoes or this Tofu, Chicken & Eggplant Curry with canned tomatoes.

Pictured: Citrus-Arugula Salad

Citrus & Iron-Rich Foods

When people think of iron, they think of steak and red meat. However, certain plant foods like leafy greens and legumes are also high in iron. However, the type of iron in plants is harder for our bodies to absorb. Vitamin C can help with that, as it enhances iron absorption in the body and allows us to get more iron from nutritious plant foods, which can be especially important for vegetarians and vegans. Try sliced orange or grapefruit on your salad to reap the benefits.

Food Combinations That Don't Work Together

Conversely, certain foods can interfere with absorption, so if you're trying to get more of one specific nutrient, like calcium or iron, avoid these food combinations. If you're an otherwise healthy person and just happen to eat these foods in combination from time to time, you don't need to worry.

Coffee & Calcium

This is unfortunate news for those with a love of lattes or milk in coffee. It is well-established in the research that the diuretic effect of caffeine makes our bodies lose calcium for up to three hours after sipping. Additionally, caffeine reduces how much calcium we can absorb in the first place, making the combination especially risky for older women. This doesn't mean having dairy in your coffee is off limits; however, it could be worth trying to work in another calcium-rich food, like yogurt or milk, at another meal or snack.

Tea & Iron-Rich Foods

Remember how we said that certain foods can enhance how much iron our body absorb from a meal? Well, there are also foods that compete with iron to be absorbed. The compounds called phytates, found in tea, are one example. They enter our body through a similar pathway as iron and should not be consumed at the same time if you're looking to increase your iron levels.

Bottom Line

Research shows that combining certain foods can help you get more of certain nutrients, which is important if you're trying to combat a deficiency. But the food combination diet being promoted today isn't that, so we suggest you skip the trend. Our digestive system is very efficient at obtaining nutrients from food, so whatever the combination and whatever the time, you'll be getting the nutrients and health benefits from what you eat. What's more important is focusing on including a variety of foods from each food group, and the nutrients will follow.

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