Food Combining Myths Busted: What Science Really Says About Eating Right

"Food combining" is a dietary trend that suggests specific foods should and should not be eaten together. Proponents claim that following these guidelines maximizes digestion and weight loss. This article explores the principles of food combining, examines the evidence supporting it, and provides a balanced perspective on its potential benefits and drawbacks.

What is Food Combining?

Food combining is a nutritional approach that involves eating certain foods together while avoiding others, based on how they digest in the body. At its core, food combining is a nutritional strategy that focuses on how different foods interact in your digestive system. This isn’t a new trend. Food combining has roots in Ayurveda, Traditional Chinese Medicine and natural hygiene principles popularized in the early 20th century.

The basic idea behind food combining is that different food groups require different digestive environments and enzymes. For example, protein-rich foods like meat, eggs, and cheese require acidic digestive environments, while starchy foods like potatoes, rice, and bread require more alkaline conditions. The diet claims that by providing rules and guidance for how to consume foods in combination, their impact on digestion and weight loss is maximized.

Food combining charts separate foods into 3 basic categories. Fresh fruit is best consumed by itself and on an empty stomach. Any two foods in the same “category” (i.e. (and so many more rules! So, basically? That fruit, yogurt and granola parfait you love? Outta the question. Apparently our bodies can’t digest that appropriately… or can they?

Historical Roots

Unlike many other diet trends, food combining has a long history. It is rooted in the ancient Indian practice of Ayurvedic medicine, which is one of the planet’s oldest holistic healing practices. Ayurveda defines every food by its taste, energy (heating or cooling) and post-digestive effect, and food combinations based on these principles are essential for optimal digestion.

The next historical round of food combining came from a physician named William Howard Hay who viewed and adapted the concept from a medical perspective. Popularized in the 1920s, the Hay Diet drew from Hay’s own personal experience with food and healing and had several strict guidelines to help a person achieve optimal health. Current food combining advocates have taken principles from both Hay and Ayurveda to create appealing food combining charts under the notion that this eating pattern will heal the gut.

Common Food Combining Principles

Food combining principles vary from expert to expert, so I’ll share a simplified version, as it’s a good starting point.

Here are some of the most common food combining rules:

Fruits: Eat fruits, especially melons, alone and on an empty stomach, as they digest rapidly. Melons are particularly fast-digesting. They don’t pair well with other fruits or any other food. Other fruits move through the body in about 30 minutes, and bananas and pears typically take about 40 minutes.
Proteins and Starches: Avoid combining proteins and starches in the same meal. Choose a protein or starch for each meal, but not both.
Fats and Proteins: Fats should not be eaten alongside proteins unless a green salad is also included.
Acids and Starches: Acidic foods like tomatoes, vinegar, citrus or fermented vegetables can interfere with the digestion of starchy foods.
Variety: Avoid too much variety in one meal. Three to four different types of foods are best.

Does Food Combining Really Work?

I won’t lie, on the surface this should make sense, right? Giving our digestive system less to “focus on” should allow it to work more efficiently… right? I won’t get into the specific details about enzymes or pH regulation (we’d be here all day) but basically our digestive system is actually a HIGHLY sophisticated process. It’s made to functions all on its own, uniquely metabolizing all the macronutrients and micronutrients our bodies need.

While traditional medicine systems have long emphasized food synergy and digestive balance, scientific evidence on strict food combining is still emerging.

Limited Scientific Evidence

Research on food combining is very sparse. Only one human study has been done to assess the health effects of this way of eating. The researchers split participants into groups to receive either a low-calorie “balanced” diet or a low-calorie “dissociated” (food combining) diet. Overall, they found significant decreases in weight, fasting blood sugar, cholesterol and blood pressure in both groups. This means that food combining didn’t make things better or worse-the outcomes were most likely the result of calorie deprivation among all participants rather than the difference in diet composition.

There is only one study to my knowledge that discusses this myth on the above mentioned food combining diet. Participants of the study were given very low calorie diets on either a food combining diet or balanced eating pattern that proved that there was no significant difference in weight loss.

One study suggests that primarily eating protein at lunch and then mostly carbohydrates at dinner could have a positive impact on diet-induced thermogenesis (the number of calories burned from digestion) and glucose levels. (source) In this study, eating primarily carbs at lunch and then protein at dinner had a negative impact on glucose, so this may suggest that timing matters when you choose a food category.

The Digestive System's Sophistication

Following a kick-start from enzymes in our saliva, carbohydrate-rich foods are primarily digested in the stomach. Proteins, however, are partially broken down in the stomach; later, the small intestine does most of the work. And fats are also primarily digested in the small intestine with the help of bile made by the liver.

The new wave of food combining also recommends separating acidic and alkaline foods for optimal digestion. However, our gut already does a good job self-regulating its acidity. No matter what is eaten, hydrochloric acid will be released in the stomach, creating a very acidic environment.

Read also: Healthy Eating on the Run

Scientists have discovered that the stomach will not empty its contents into the intestinal system until everything in it has been properly broken down. The stomach cannot select individual ingredients from your meal and send them on separately. There is a sensor in the duodenum that tests small samples from the stomach to determine if the meal you just ate has been processed enough to be sent on to the intestines. If it has, digestion proceeds smoothly. If it hasn’t, the valve is closed and the stomach works a while longer.

Potential Benefits

Despite the lack of strong scientific evidence, some people report experiencing benefits from food combining, such as:

Improved Digestion: Some individuals find that following food combining principles reduces bloating, gas, and other digestive discomforts. Careful food combining can dramatically improve the quality of digestion, support the body in receiving a deeper level of nourishment, and positively impact our overall health.
Increased Energy: By easing the digestive process, some people feel more energized and experience fewer energy crashes after meals. Fewer energy crashes or post-meal fatigue.
Weight Management: Simplifying meals and being more mindful of food choices may lead to reduced calorie intake and weight loss.
Mindful Eating: Food combining encourages greater awareness of food choices and their impact on the body.

One reason you may feel that way is that digestion takes energy. According to the Mayo Clinic, approximately 10% of the calories we consume are used for digestion and nutrient absorption. That’s where food combining comes in. I was introduced to the concept of food combining while reading The Raw Food Detox Diet. The general idea is that you can ease digestion by not eating too many dense foods all at the same meal. Instead, you’ll pick one category-such as animal protein, for example-then fill the rest of your plate with raw or cooked non-starchy vegetables, like a green salad and roasted cauliflower.

Potential Drawbacks

Restrictive: Food combining can be quite restrictive, making it difficult to maintain in the long term. The rules laid out on this food combination chart may feel overwhelming-even irritatingly complicated. But, the rationale behind proper food combining really does make sense.
Socially Inconvenient: Following strict food combining guidelines can be challenging in social situations and when eating out.
Unnecessary: The human digestive system is designed to handle a variety of foods eaten together. There is zero reason you can’t have fruits with other food.
Potential for Nutrient Deficiencies: Overly restrictive diets can lead to nutrient deficiencies if not carefully planned.

Honestly, I think one reason people do this diet is because it makes eating so freaking complicated that it’s easier to just NOT. Therefore, some see weight loss in the short term. But that isn’t from the food combining… it’s from eating less food likely due to the food fear or getting food combining “wrong”. Furthermore, about weight: I don’t advocate for intentional weight loss. If you follow me at all you know that. We now know (thanks to the HAES movement) that health promoting behaviors NOT weight are what decreases mortality and disease risk.

Food Combinations That Work

Despite what food combining advocates think, there is research that encourages the consumption of nutrients and foods in combination with each other. For example, eating a high-carbohydrate food, like fruit, with a high-protein food, like Greek yogurt or almonds, could slow the absorption of glucose into the blood. Food combining also leaves out some important combinations that may help with the absorption of vital nutrients. Combining vitamin C-rich foods, like oranges and other acidic fruits, with iron-rich foods, like animal proteins or dark green leafy vegetables, may improve iron absorption. Vitamin C is particularly beneficial for improving the absorption of non-heme iron, which is found in plant sources. Additionally, eating foods like vitamin A-rich sweet potatoes or vitamin K-rich broccoli with a high-fat food can improve vitamin absorption.

Through the sports nutrition lens, we know that simple carbohydrate consumption (think fruit: applesauce, gummies and ‘white’ or refined starches: bread, pretzels, cereal) can be helpful to boost our workouts when consumed prior and during our workouts, though is highly specialized to the type of training (strength v. cardio), timing (how many hours prior to working out), and individual’s gut tolerance (using simple v. complex carbohydrates). So, sure. If you’re about to head to the gym and want some quick energy then focus on quick carbs. Actually… do the opposite of what the food combing chart says! Consuming fat (such as with nuts) with fruits that are high in fat soluble vitamins (A, D, E, K) are helpful in improving vitamin absorption. This is one of the many reasons why trail mix tastes SO good!

We know for those with hormone irregularities (think Diabetes, PCOS, and other hormone disorders), the type of carbohydrate (simple v. complex) and combining protein and fat with carbohydrate sources can help to slow carbohydrate absorption which is important to improve blood sugar regulation. We also know that carbohydrate and protein consumption following exercise is crucial to restore glycogen stores (where we store energy in our bodies), to grow muscles, and to not inhibit performance.

Consuming collagen (a protein) with vitamin C (found in fruits) is important in synthesis of collagen in our bodies during times of illness or body composition for performance. Consuming vitamin C with iron (found in poultry, meat, and fish) can also help with iron absorption. Additionally, like we already mentioned, adding protein and fat to carbohydrates for those with hormonal disorders such as diabetes (Type I or Type II) and polycystic ovary syndrome (PCOS) eating carbohydrates paired with fats and protein can be beneficial for improved blood sugar regulation.

How to Incorporate Food Combining (If You Choose To)

You don’t have to overhaul your entire lifestyle to try food combining. Here’s a one-week food combining meal plan based on the most common food combining rules, designed to support digestion, energy and potentially weight loss. Portions are adjusted to personal needs.

If you're curious about experimenting with food combining, here are some tips:

Start Slow: Don’t overhaul your diet overnight. It is usually best to embrace the idea of food combining slowly and gently, allowing plenty of time to make the necessary adaptations.
Listen to Your Body: Pay attention to how different food combinations affect your digestion and overall well-being.
Focus on Whole Foods: Emphasize whole, unprocessed foods in your diet, regardless of whether you follow food combining principles.
Stay Hydrated: Drink plenty of water to support healthy digestion.
Don't Be Too Restrictive: Remember, food combining is not about imposing black and white rules.

Food Combining Chart

The following food combining chart highlights incompatible food groups and offers suggestions for more appropriate combinations. It is meant to be a helpful guide, not an exhaustive list. In fact, you may be aware of other combinations that do not work for your body. For the incompatible food combinations listed here, you may wonder how long you should wait between consuming each separate food. Everyone's digestion is different-some people are fine with waiting half an hour while others need an hour or two between meals. Because this resource is meant to help you determine optimal combinations at a glance, there is some repetition.

Incompatible Food Combinations

Fruit with Vegetables: Fruits and vegetables at the same meal. If the digestion is feeble, the use of both will often cause distress and inability to put forth mental effort.
Bananas and Milk: Though commonly eaten together, bananas and milk are challenging to digest together because their qualities are so different. Bananas are heating while milk is cooling. That alone is problematic. Further, bananas become sour as they break down. Ever added a squeeze of lemon to milk? Or maybe you've poured a little milk into a tangy, fruity tea… only to watch it curdle instantly? When bananas and milk are eaten together, their opposing qualities tend to smother the digestive fire and can disrupt the balance of intestinal flora, which results in the creation of toxins. This combination also frequently causes congestion, colds, coughs, allergies, hives, and rashes.
Sour Fruit with Milk: A similar situation arises when we combine any sour fruit with milk. You may be wondering if this goes for alternative milks as well, such as almond milk or oat milk. This combination is simply too taxing for the digestive fire.
Nightshades with Cheese: Yes, some of these are staple combinations in many households. Pizza and a number of other beloved Italian dishes combine nightshades with cheese. Nightshades contain alkaloids, primarily as a means of defense against being damaged by insects. The alkaloids can be anywhere from mildly to fatally toxic to humans. As a result, diverse cultures around the world have long held an intriguing relationship with the nightshade family. Some have been used to make poisons, some contain incredibly addictive compounds such as nicotine, some are mind-altering, and others create an incredible sensation of heat in the mouth. The bottom line is that nightshades contain a complex array of compounds that, once ingested, lead to a potentially dramatic cascade of chemical reactions in the body.
Beans and Cheese: Beans and cheese are similar in that they both tend to be heavy and are often difficult to digest. In order to break down properly, they both require a good deal of digestive strength. But, the similarities end there. Beans tend to taste mostly astringent and sweet, can be either heating or cooling (depending on the type of bean), and usually have a pungent post-digestive effect. The post-digestive effect of different foods occurs once that food has moved into the colon; it affects the urine, feces, sweat, and tissues-sometimes even at the cellular level. This is the case with beans and cheese; when they are eaten together, they tend to overwhelm and confuse the digestive fire.

Compatible Food Combinations

Grains with Vegetables: You'll notice that grains are recommended with just about everything but fruit. Combining rice with dal results in kitchari, which Ayurveda considers one of the top easy to digest foods and recommends as the meal of choice to eat throughout a traditional Ayurvedic cleanse. Kitchari also contains ghee, digestive spices, and can be paired with several varieties of vegetables.
Fruits and Neutral Foods: Fruits and neutral foods can be combined in dishes like oatmeal with raisins or waldorf salad.
Vegetables and Neutral Foods: Vegetables can be combined with neutral foods in dishes like vegetable stew, lentil soup, and lasagna.
Vegetable Fruits with Any Other Foods: “Vegetable fruits” such as avocados, cucumbers, tomatoes, bell peppers, and olives are classified as "magic" or "star" foods and can be eaten with any other foods: Other fruits, vegetables, starches, and proteins.

Examples of Properly Combined Meals

Here are some examples of properly combined meals, choosing ONE category and only eating foods out of that category for that particular meal:

Veggie Sandwich: Start with whole-grain bread filled with avocado, mustard, lettuce, tomato, and sprouts. Serve with a leafy side salad and a baked sweet potato topped with butter.
Pasta with Vegetables
Quinoa Salad: Any grain-based salad topped with beans, veggies, and avocado will work. Try my Quinoa Black Bean Salad or Quinoa Chickpea Salad for properly combined recipes.
Baked Potatoes: Sweet potatoes or white potatoes topped with veggie chili would be a hearty option.
Soup: Hearty vegetarian soups, like Lentil Soup or Black Bean Soup, are easy options.
Meat and Fish Entrees: Serve baked chicken breasts or the best baked salmon over a large, leafy green salad, or with a side of roasted cauliflower or broccoli.
Veggie Pizza Crusts: Try my cauliflower pizza crust or zucchini pizza boats topped with cheese and your favorite toppings.
Spiralized or Shredded Pasta Alternatives: Instead of pasta, try sautéed cabbage, a bed of steamed cauliflower, or zucchini noodles with your favorite meatballs or meat-based spaghetti sauce on top. You can add Parmesan cheese on top to make it ultra-comforting.
Salad with Nuts: For a main course, try a large leafy green salad topped with dried cranberries and raw walnuts, along with plenty of extra non-starchy vegetables for added texture. I also love a shredded carrot salad with raisins and nuts, or tahini dressing for a creamy salad.
Bean-Free Hummus: Try my zucchini hummus served with sliced veggies as an appetizer for a nut-based meal.
Grain-Free Breakfast Cereal: Start your morning with a bowl of Paleo Granola topped with almond milk.
Nut-Based Desserts: Try a slice of raw cheesecake or a coconut macaroon after your nut-based meal.

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