Food Combining

Some people try to follow a balanced diet and count calories to improve their health and/or lose weight.

Others believe that mixed meals are bad for their health – that meat and potatoes or bread and cheese should not be eaten together because it is bad for gut health, etc.

They believe that for optimal digestion carbohydrates, fats and proteins should be eaten separately.

Here we look at whether food combining can improve our health and help us lose weight, or is it just another fad diet?

First, a little history

Unlike many other diets, food combining (eating certain foods in combination and avoiding certain combinations to optimise digestion and overall health) has a long history. Its roots can be traced back to ancient Indian Ayurvedic medicine, one of the oldest holistic healing practices.

1. Ayurveda, a traditional Indian system of medicine that goes back more than 5,000 years, emphasises the importance of combining foods to keep the body in balance (to prevent digestive problems and promote health), for example, it recommends avoiding eating dairy products with meat or fruit.

2. Traditional Chinese medicine, which has a history of more than 2000 years, includes food combining principles based on the balance of Yin and Yang, as well as the theory of the five elements, and recommends combining foods that harmonise with the body’s energies and avoiding those that may cause internal imbalances.

3. Hay diet. In the 1920s, William Howard Hay developed the “Hay diet”, a system of food combinations that aimed to improve health. Howard Hay divided foods into three groups: alkaline, acidic and neutral and recommended not eating protein and carbohydrates together in one meal and eating acidic and alkaline foods separately.

4. Herbert M. Shelton, one of the most prominent members of the Natural Hygiene movement of the mid-20th century, continued to promote the principles of food combining. Shelton focused on optimal digestion, advocating the separation of protein and starchy foods and eating fruit separately.

5. In the 1980s, Harvey and Marilyn Diamond introduced the concept of food combining to a wider audience with the bestseller “Fit for Life“. It recommended eating fruit on an empty stomach and combining foods according to their compatibility with the digestive system, for example by not mixing proteins with carbohydrates.

What is food combining?

Food Combining is a nutritional model that combines certain foods and avoids certain food combinations to improve digestion and overall health.

The concept is based on the idea that different foods are digested at different rates and require different digestive environments (different enzymes, pH levels, etc.), so combining them incorrectly can cause digestive problems and reduce nutrient absorption.

In other words – the mixed food we traditionally eat is poorly digested due to the conflict between different digestive enzymes, causing fermentation of carbohydrates, putrefaction of proteins in the stomach and thus intoxication of the body with all the consequences that this entails.

Food Combining diets became popular in the early 1990s with the rise of the Natural Hygiene movement. A new branch of science was even created to promote this concept – “trophology”, the science of food combining.

Food Combining diets divide foods into food groups and determine how these groups should be combined in meals. Typically, foods are divided into carbohydrates and starches, fruits (and more specifically sweet fruits, sour fruits and melons), vegetables, proteins and fats.

But.

In some Food Combining diets, foods are also classified as acidic, alkaline and neutral.

Basic principles of food combining diets

1. Combining different types of protein (e.g. meat, fish, eggs and legumes) should be avoided and protein should not be eaten with starch/carbohydrates (e.g. bread, potatoes, rice and pasta). Mixing these products is thought to cause digestive upset, as protein is supposed to require an acidic environment for digestion and starch/carbohydrates an alkaline environment.

2. Fruit, especially sweet fruit, should be eaten alone or in combination with other fruit, as if eaten with slower digesting foods they can ferment in the stomach and cause bloating and gas.

3. Fats (such as oils, butter and avocados) can be eaten with protein.

         However.

         Fats can slow down protein absorption, so they are recommended to be eaten with protein in moderation.

4. Vegetables (such as leafy greens, broccoli and peppers) can be combined with protein or starch. They are considered neutral and well-digestible with both protein and starch.

5. Acidic foods (e.g. citrus fruits, tomatoes and vinegar) should not be combined with starch as the acidity may interfere with the digestion of starch.

6. Dairy products, especially milk, should only be consumed on an empty stomach.

Beliefs behind the food combining

The rules of the food combining are mainly based on two assumptions:

1. Foods are digested at different rates and combining fast-digesting foods with slow-digesting foods causes “congestion” in the digestive tract, which negatively affects health and digestion.

2. Different enzymes are needed to break down different foods and these enzymes work at different pH levels (acidity levels) in the gut. In other words, if two foods require different pH levels to be digested the body cannot properly digest both simultaneously.

Proponents of food combining believe that following these principles is essential for good health and digestion and that ignoring them leads to negative consequences such as digestive disorders and disease.

What does the science say?

The only study I could find on the principles of food combining was one conducted in 2000, which looked at whether a diet based on food combining affected weight loss.

Participants were split into two groups and given either a diet based on the principles of food combining or a balanced mixed diet (the calorie intake was the same in both cases – 1100 Kcal/day).

After 6 weeks, participants in both groups had lost an average of 6-8 kg of weight. In other words – food combining had no advantage over a balanced mixed diet.

In fact, there is no evidence to support most of the principles of food combining.

Furthermore.

Many diets based on food combining were developed about 100 years ago when much less was known about nutrition and digestion.

Current knowledge of nutritional science and biochemistry directly contradicts most principles of food combining.

On avoiding mixed meals

The term “mixed meals” refers to meals containing a combination of all three macronutrients – protein, carbohydrate and fat.

The rules of food combining are largely based on the idea that the body is not adapted to digest such a mixed diet.

However.

This is not the case, as the human body has evolved over thousands of years to process a complete diet, which almost always contains carbohydrates, proteins and fats.

Vegetables and cereals, for example, are generally considered sources of carbohydrates.

However.

They also contain protein.

Meat is considered a source of protein.

But.

Even lean meat contains a certain amount of fat.

In other words, it is impossible to separate and eat only carbohydrates, proteins or fats when eating everyday foods.

And.

Since the human digestive tract has historically evolved from eating mixed meals- it is ideally adapted for processing mixed foods:

• When food enters the stomach, stomach acid and the enzymes pepsin and lipase are released, which help initiate the digestion of proteins and fats. And, studies show that pepsin and lipase are released even when there is no protein or fat in the food.

• The food then passes into the small intestine. There, stomach acid is neutralised and the intestines are flooded with enzymes that break down proteins, fats and carbohydrates.

In other words, there is no need to worry about choosing between digesting protein, fat or starch – the body is perfectly adapted for such multi-tasking.

On food altering the pH of the digestive tract

Another claim in the theory of the split diet is that combining the wrong foods can inhibit digestion by creating a pH level that is unsuitable for the activity of certain enzymes.

pH is a measurement of how acidic or alkaline a solution is. It ranges from 0 to 14, where 0 is the most acidic, 7 is neutral and 14 is the most alkaline.

It is true that enzymes need a certain pH range to work properly and that not all enzymes in the digestive tract need the same pH.

However.

Eating more alkaline or acidic foods does not significantly change the pH of the digestive tract, and the body has several ways of keeping the pH of each part of the digestive tract within the correct range, for example:

• The pH of the stomach is usually very acidic (pH 1-2.5) and may initially rise to pH 5 after eating. However, more stomach acid is then quickly released until the pH falls back to pH 1-2.5, as this low pH helps to start the digestion of proteins, activates enzymes produced in the stomach and also helps to kill bacteria in the food.

While

• The small intestine is not adapted to such an acidic pH and as soon as stomach contents enter the small intestine, bicarbonate is added (the body’s natural balancing system). This is highly alkaline, so it neutralises the stomach acid, keeping the pH at around 6-7 the level at which the small intestine enzymes work best.

In other words, the level of acidity in different parts of the digestive tract is very well controlled by our body – when we eat very acidic or alkaline foods, it adds more or less digestive juices to the stomach to achieve the required pH level.

On food fermenting in the stomach

Another assumption about the consequences of incorrect food combining is that food ferments or putrefies in the stomach – combining fast-digesting foods with slow-digesting foods causes the fast-digesting foods to stay in the stomach so long that they begin to ferment.

However, this does not happen.

Fermentation and putrefaction begin when microorganisms start to break down (digest) the food. But, as I mentioned earlier, the stomach has such an acidic pH that almost no bacteria can survive there.

In the digestive tract, bacteria thrive in the large intestine, where trillions of beneficial bacteria live and ferment undigested carbohydrates, like fibre, and release gas and beneficial short-chain fatty acids as waste products.

And.

In this case, fermentation is a good thing, because the fatty acids produced by the bacteria are associated with health benefits such as reduced inflammation, better blood sugar control and a lower risk of colon cancer.

In other words, the gases produced after eating are not necessarily bad, but rather a sign that the friendly bacteria in our bodies have been well nourished.

Evidence-based examples of food combinations

Although the principles of food combining diets are not scientifically based, this does not mean that food combining is always pointless.

For example, many food combinations can significantly enhance or reduce the absorption of certain nutrients.

Here are some examples.

Citrus fruits and iron

Iron is present in the diet in two forms:

1. Heme iron, found in meat;
2. Non-heme iron, which is found in plants.

Heme iron is well absorbed, while non-heme iron is absorbed only between 1 and 10%.

Adding vitamin C is one of the most effective ways to increase iron absorption – in addition to promoting the absorption of non-heme iron, vitamin C also reduces the ability of phytic acid to block iron absorption.

In other words – by combining foods rich in vitamin C (such as citrus fruits and bell peppers) with plant sources of iron (such as spinach, beans and iron-fortified cereals) we can increase iron absorption.

Carrots and fat

Some nutrients, such as fat-soluble vitamins and carotenoids, require fat to be absorbed by the body.

Carotenoids are compounds found in red, orange and dark green vegetables including carrots, tomatoes, red bell peppers, spinach and broccoli.

Studies have shown that a diet rich in carotenoids can reduce the risk of certain health problems, for example, certain cancers, heart disease and vision-related problems.

However.

Eating these vegetables without fat, for example, by gnawing on a carrot or eating a salad with a fat-free dressing, might not give you the benefits of carotenoids.

Therefore.

To get more carotenoids into your body, it is better to eat vegetables containing carotenoids with foods containing healthy fats, such as nuts, seeds, olive oil or avocados.

Spinach and dairy products

Foods such as spinach, beetroot, potatoes, chocolate and tea contain oxalate – an antinutrient that can bind with calcium to form an insoluble compound.

Depending on the circumstances, this can be both good and bad:

• For people prone to kidney stones, consuming calcium sources such as dairy products with foods containing oxalate can reduce the risk of kidney stones.

On the other hand.

• Combining oxalates and calcium reduces calcium absorption. This is not a problem for most people on a balanced diet, but for those on low calcium but high oxalate diets, this interaction can cause problems.

Key takeaways

Most of the principles of food combining diets are not backed by science and there is no evidence to show that incorrect food combining contributes to disease or toxins in the body.

Modern nutritional science and research show that although some food combinations may affect the speed of digestion or the absorption of nutrients, the body’s digestive enzymes can generally process mixed food efficiently.

No evidence supports the health or weight loss benefits of food combining diets.

In addition.

The strict rules of these diets are not sustainable because they are too difficult to follow in the long term.

If you want to improve your health or lose weight there is nothing better than a balanced, nutritious diet and controlling your calorie intake.

And.

This means that you don’t have to exclude your favourite foods from your diet, but you do have to think about how much and what you eat.

Eat delicious, eat balanced and – be healthy!