A Personal Trainer's (Expert) Take on the Food Combining Diet

diet digestion food health wellness Apr 15, 2024

As a certified personal trainer with 35 years of experience guiding clients toward their fitness goals, I've encountered almost every type of diet.

The Food Combining Diet has piqued my interest due to its potential benefits for digestion and overall well-being. In this article, we'll delve deep into this diet, exploring its origins, principles, science, and real-world implications.

Does the Food Combining Diet really stack up?

Read on to find out.

Understanding the Food Combining Diet

The Food Combining Diet, commonly known as the Hay Diet, dates to the early 20th century. William Howard Hay, a New York doctor, developed the idea in response to his own health issues.

He thought his health problems stemmed from eating the wrong foods together. In 1930, he wrote a book titled "Health via Food," which outlined the tenets of the Food Combining Diet.

Dr. Hay's central thesis was that various food kinds necessitate various digestion conditions in the stomach. For instance, he said that proteins and carbs shouldn't be consumed because their digestion requires different pH levels and enzymes.

He contended that eating these items together would cause bloating, indigestion, and other health issues. Dr. Hay developed the following rules that have become the foundation of the Food Combining Diet:

Do not eat proteins and carbohydrates together.
Eat fruits on their own
Eat dairy products on their own
Separate starches and acidic foods (i.e. breads and tomatoes)
Eat veggies first, then proteins, and then carbs
Do not drink water with meals

There are two underlying beliefs with this diet:

Different types of food are digested at different speeds. This can cause congestion of the digestive tract.
Different types of food need different enzymes, with different pH levels, to break them down. Combining them creates a less-than-ideal pH environment that prevents proper digestion.

Proponents of the diet believe that improper food combining creates a toxic build-up that results in disease and distress.

Does Science Support the Food Combining Diet

The concepts underlying the Food Combining Diet have not yet been extensively studied in science. In fact, there has been just one study, from 2000, on the subject, and it was focused on weight loss.

Two study groups were fed either a balanced diet or a diet that followed the food combining principles. Both diets totaled 1100 calories daily.

After six weeks, participants in both groups had lost an average of 13 to 18 pounds (6 to 8 kilograms). There was no significant difference between the two groups, suggesting that Food Combining does not improve weight loss.

What about the claims that food combining promotes improved digestion and can prevent disease and illness?

Even though there are no specific studies to substantiate these claims, we do know a lot more about digestion and nutrition than when Dr. Hay created the Food Combining Diet.

And it appears that many of the ideas of food combining appear to be directly at odds with modern knowledge in the fields of fundamental biochemistry and nutritional research.

Consider the two underlying precepts we identified in the last section:

Mixed-Meal Digestion

One foundational idea in food combining contends that the body has trouble processing meals that combine proteins, carbs, and fats. The biological reality, however, runs counter to this claim.

Nearly all foods contain all three macronutrients to some degree. So, fruits contain some protein, steak contains some fat, and chicken contains some carbs.

As a result, the digestive system was designed to process all three macronutrients simultaneously.

The breakdown of proteins and lipids (fats) begins as soon as food enters the stomach when gastric acid and digestive enzymes such as pepsin and lipase are released. Research has found that these enzymes are still secreted even when the meal is low in fat or protein.

As food enters the small intestine, stomach acid is neutralized, and the area is flooded with enzymes that speed up the breakdown of proteins, lipids, and carbs. As a result, the human body can easily manage the digestive process of mixed meals.

Combining pH Levels

The idea that the wrong meal combinations might change the pH levels to impede digestion is another premise underlying food pairing. Although eating foods with varied pH levels has a minimal influence on the pH of the digestive tract, enzymes still require particular pH ranges to function properly.

However, the body has systems in place to keep the pH of each section of the digestive system in the desired range. For instance, the stomach maintains a highly acidic environment that is necessary for the breakdown of proteins and the eradication of bacteria.

Even if a meal initially causes the pH to rise, extra stomach acid is quickly generated to quickly bring back the required acidity.

It's a popular misconception that mixing meals improperly causes stomach putrefaction or fermentation. According to this theory, when fast- and slow-digesting foods are taken together, the fast-digesting portion stays in the stomach for an extended period of time and causes fermentation.

But that's not how the body operates. When bacteria begin to break down food, fermentation and rotting ensue, but the stomach's extremely acidic pH makes this environment unfavorable for these bacteria.

Instead, the colon, commonly known as the large intestine, is home to trillions of good bacteria that use undigested carbs to produce healthy short-chain fatty acids and gas.

From these examples, we can see that our knowledge of human physiology directly contradicts the principles of the Food Combining Diet.

My Experience with the Food Combining Diet

Over the years, I've encountered several scenarios where former clients tried the Food Combining Diet but found it too demanding and impractical for various reasons. Here's an overview of their experiences:

Many clients lead busy lives with demanding schedules. For them, adhering to the rigid rules of food combining, such as consuming fruits separately from other meals, often proved impractical. It's difficult to manage when you're constantly on the move or have limited access to specific foods.
Clients often faced challenges when dining out or attending social events. The diet's strict guidelines made it challenging to enjoy meals with friends and family without constantly worrying about food combinations. This social aspect can lead to feelings of isolation and frustration.
Despite committing to the Food Combining Diet, some clients found that their digestive issues, which initially prompted them to try the diet, persisted. This was disheartening, as they had high hopes that the diet would alleviate their discomfort.
From a fitness perspective, the Food Combining Diet can sometimes result in nutritional gaps. Some clients struggled to ensure they were getting a well-rounded intake of essential nutrients when certain food combinations were off-limits.

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My Food Combining Diet Tips

By now, you may have realized that I'm not a fan of the Food Combining Diet. I personally would not follow this diet, nor would I recommend it to my clients. However, if you are determined to give it a try, here are some guidelines to keep in mind:

Evaluate Your Lifestyle: Consider how well the diet fits with your daily schedule and social obligations. If your way of life makes it difficult to follow the stringent rules, think about other nutritional strategies that are likely more practical for you.
Keep Track of Your Digestive Comfort: Monitor how the diet impacts your ability to maintain digestive comfort. If you discover that it doesn't offer the relief you're looking for, don't be afraid to look into different nutritional plans or speak with a healthcare provider for more advice.
Balance Your Nutrient Intake: Make sure that your food intake enables you to sufficiently meet your nutritional needs. If you're worried about nutrient deficiencies, engage with a certified dietitian to create a balanced meal plan that takes into account your unique dietary objectives.

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Food Combining That Works

Even though the general principles behind the Food Combining Diet don't stack up under scrutiny, that doesn't mean that all food combining is pointless. Here are some examples of smart food combining that can improve your digestion and absorption of those foods. Here are some examples:

Dairy Products + Spinach: Combining dairy products like yogurt or cheese with spinach can be beneficial. Spinach contains calcium-blocking compounds called oxalates, which can hinder calcium absorption. However, the probiotics found in yogurt or the vitamin K in cheese may counteract this effect by promoting better calcium utilization.
Carrots + Dietary Fats: Combining carrots with such healthy fats as avocadoes, almonds, or olive oil increases absorption. That's because the dietary fats provide fat-soluble vitamins such as beta-carotene.
Avocado + Leafy Greens: Adding creamy avocado slices to leafy green salads improves the flavor and increases nutritional absorption. The avocado's healthy fats help your body absorb the fat-soluble vitamins A, K, and E.
Black Pepper + Curcumin: Curcumin is a powerful anti-inflammatory that comes from turmeric. Adding black pepper to curcumin increases its absorption and bioavailability.
Legumes + Whole Grains: Mixing whole grains and legumes creates a complete protein source. For example, combining brown rice with chickpeas will give you all nine essential amino acids. This can be important to help vegans and vegetarians meet their body's protein needs.
Tomatoes and olive oil: Tomatoes contain the powerful antioxidant lycopene. However, it is fat soluble, so combining it with olive oil will boost its absorption.
Eggs + Spinach: Pairing eggs with spinach is a nutritious duo. The vitamin D in eggs aids in calcium absorption from spinach, supporting better bone health.
Iron + Citrus: Iron from plant-based sources (non-heme iron) is better absorbed when consumed with vitamin C-rich foods like citrus fruits. The vitamin C in oranges, lemons, or grapefruits helps convert non-heme iron into a form that your body can readily absorb, making this a smart food combination for individuals following a vegetarian or vegan diet.

For more ideas on proper nutrition, check out our guide on how to start eating clean.

Make Sure to Get Your Fruits & Vegetables

As a personal trainer, I have many clients who have established a pattern of neglecting the nutritional powerhouses of the diet – fruits and vegetables. The importance of fruits and vegetables in improving general health and well-being cannot be understated.

They ought to be a staple of any balanced diet, regardless of whether you adhere to any particular dietary rules. Include high-calorie vegetables occasionally. Consider these benefits:

Nutrient Density: Despite having a low-calorie count, fruits and vegetables are dense in important nutrients. They provide the vitamins and minerals your body needs for the generation of energy, the functioning of your muscles, and general vigor by incorporating them into your meals.
Digestive Health: The fiber in fruits and vegetables promotes a healthy gut microbiota and improves digestion.
Antioxidant Content: Vegetables and fruits are a superior source of oxidative stress and inflammation-fighting free radicals. Antioxidants are especially important for people who work out as they can help with recovery and protect muscle cells from free radical damage.
Weight Control: The fiber in fruits and vegetables will help fill you up, helping you achieve the negative calorie balance needed to lose body fat.

A well-rounded fitness program should also include resistance training and stretching. I recommend incorporating some yoga poses to your stretching routines.

One of my favorite pieces of training equipment is a kettlebell. In fact, I believe that only a kettlebell can help you pull out a great workout.

Wrap-Up

In my 35 years of experience as a certified personal trainer, I've witnessed the rise and fall of countless diets, each with its own unique promises and principles. The Food Combining Diet, with its historical roots and distinct set of guidelines, is no exception.

The diet's principles, developed over a century ago, do not align seamlessly with modern scientific knowledge. However, this doesn't diminish the importance of its underlying message: the significance of mindful and balanced eating.

From my perspective as a personal trainer, I've often found that individuals who embark on diets like the Food Combining Diet may inadvertently overlook a fundamental aspect of nutrition – the abundant role of fruits and vegetables. Dietary principles or restrictions do not bind these natural powerhouses; they are essential for everyone, regardless of their chosen dietary path.

Whether you're a fervent follower of food combining or a skeptic seeking balance, remember that no diet is one-size-fits-all. Consider your lifestyle, nutritional goals, and digestive comfort as guiding factors in your dietary choices.

Seek to embrace a balanced approach to nutrition that values the wide variety of fruits and vegetables alongside other food groups for optimal health and wellness.