In part one of Dr Linia Patel’s two-part series on food combining, she looks at the common beliefs and rules involved and what the science says when it comes to the art of food combining.
Working in the nutrition world is never boring. There is a constant stream of trends for one to research and learn about. Some trends are on to something and are here to stay. Many others are simply fads and have little science-based backing. The latest trend? Separating out your macronutrients (i.e., protein, fat and carbohydrates) from meal to meal for optimal digestion. It’s more commonly known as ‘food combining’. This blog will come to you in two parts. Part one will help you understand exactly what food combining is, the common rules involved and what science says. Part two will give my clinical verdict as a dietitian and public health researcher.
Beliefs behind food combining
Unlike many other diet trends, food combining has a history that is rooted in the ancient Indian practice of Ayurvedic medicine. Although it’s important to remember that food is only one component of Ayurveda, it defines every food by its energy (heating or cooling) and post-digestive effect. The belief is that improper food combining leads to digestive distress and disease.
In the 1920s, a physician named William Hay popularised the idea of food combining, adding in his own personal experiences of using ‘food as medicine’ and proposing these principles:
- Leave at least four to five hours between meals.
- Eat whole, unprocessed foods.
- Do not combine starches or sugars with protein or acidic fruits.
- Eat mainly vegetables and fruit.
- Eat proteins, starches and fats in moderation.
The above rules of food combining are based on two beliefs. The first is founded on the different rates at which food is digested. Combining fast-digested food with slow-digested food causes a ‘traffic jam’ in your digestive tract, which leads to digestive distress and disease. The second is that different foods require different levels of acidity or pH in your gut for proper digestion.
The current food combining advocates combine principles from Ayurveda, Hay and the alkaline diet to create food combining charts and an eating pattern that aims to optimise or heal the gut.
Food combining rules
Food combining rules are based on the idea of enhancing digestion by pairing foods that require similar digestive processes. However, at the core are principles that advocate for eating whole, unprocessed foods and ensuring you are getting a balanced diet with all the necessary nutrients, even while following food combining principles.
Food combining principles include:
- Eat fruit only on an empty stomach, especially melons.
Rationale: Fruits and especially melons digest very quickly and can ferment if eaten with slower digesting foods like proteins or starches.
- Consume dairy products on an empty stomach, especially milk.
Rationale: Dairy products can be hard to digest and may cause fermentation if combined with other foods.
- Combine proteins (meat, fish, eggs) with non-starchy vegetables (i.e., green veggies, peppers, salad, etc.).
Rationale: Proteins require an acidic environment for digestion, while non-starchy veggies can be digested in both acidic or alkaline environments.
- Avoid combining starches with acid foods. Eat starch and protein at separate meals.
Rationale: Starchy carbohydrates like rice, bread and potatoes require an alkaline environment for optimal digestion, so avoid combining with proteins that require an acid environment. Combining them will lead to digestive discomfort.
- Eat fats (avocado, oils, butter) with non-starchy vegetables.
Rationale: Fats can delay the digestion of proteins, causing potential digestive issues.
- Limit liquids during meals. Drink water and liquids before or after meals.
Rational: Drinking large amounts of liquid with meals can dilute stomach acid and impair digestion.
What does the science say?
To date, only one study has looked at the principles of food combining through a science-based lens. A study by Golay et al explored the impact of food combining on weight loss. Subjects in the study were split into two groups. The control group was given a balanced diet. The intervention group was given a diet based on food combining. Both diets were 1,100kcal. After six weeks, the results showed both groups lost the same amount of weight, supporting the notion that food combining is not superior to normal balanced eating. A limitation of the study, of course, is that it didn’t report on digestive habits or include blood markers. Although the research on this specific diet is limited, many dietitians and nutrition experts are able to use basic biochemistry and nutritional science to really look at the validity of the claims. Read part two to find out more …
References:
- Golay et al (2000), Similar weight loss with low energy food combining or balanced diets, Int J Obes Relat Metab Disord., 24(4): 492-6.
Watch out for part 2 … COMING SOON!
