What is Food Combining + Should You Do It?

by | May 25, 2020 | Digestive Health, Nutrition Articles

If you’re familiar with food combining, you may have wondered if it’s beneficial to practice. In this post we’re covering what it is, how it works, and if we should do it.

There are many diet trends out there. Some that have valid principles, while others not so much.

If you keep up with the latest happenings in the wellness world on social media or otherwise, you’ve probably heard of food combining. Every now and then I receive a message or email from someone about it, and whether or not they should be doing it.

I completely get it. Like every other diet trend out there, reading about the various rules and the claims behind them creates a lot of confusion. One moment we hear one thing, and the next we hear something entirely contradictory.

Perhaps one of the most contradicting diet trends is with food combining. If you’re a follower of food combining, please know two things: 1) I applaud you for having an interest in ways that you can support your health (also, I once-upon-a-time practiced some of the rules, too), and 2) there are some food combining rules that are, in fact, useful. Although they’re not quite the same as the food combining rules we’re talking about today. We’ll get into those at the end.

But for now, let’s dive in to the topic at hand: food combining. What is it, how does it work, and should we be doing it?

What is Food Combining?

Food combining is a set of dietary rules rooted in Ayurvedic medicine. Additionally, the Hay Diet created by 1920s physician William Howard Hay, resembled today’s food combining rules. These rules outline certain foods that should be eaten together and apart. As such, it’s less about what to eat, and more about how. It suggests that the body is not equipped to digest mixed meals (meals with carbohydrates, fats, and protein).

Food combining is based on principles of enzymatic activity and rate of digestion. These principles are based on the notion that different foods require different enzymes to break them down and that these enzymes work at different pH levels (acidity/alkalinity) in your gut. Specifically, protein requires an acidic environment and carbohydrates require an alkaline environment. As a result, the body cannot properly digest them all simultaneously. It’s also based on the notion that because different foods are digested faster or slower than others (e.g. starch vs. protein), fast and slow digesting foods eaten together cause a “backup” in your digestive tract due to improper or incomplete digestion.

By following food combining rules, it’s believed that fermentation causing bloating, gas, and other symptoms of digestive distress can be prevented, and our bodies tissue and fluid pH levels can be balanced.

Food Combining Rules

There are several food combining rules floating around the internet, but here are some classic characteristics:

  • Fruit should be eaten on an empty stomach, and it should only be ripe
  • Fruits and vegetables should be eaten separately
  • Do not combine starchy carbohydrates with acid, fruit, or protein
  • Consume protein alone or with vegetables
  • Consume starch and vegetables together
  • Consume raw food before cooked food

Some examples of poor food-combining meals include granola (fruit, starch, protein), sandwiches (starch, protein), and nut butter on toast (protein, starch).

Whew! That’s quite the set of rules. Aside from a lack of evidence to support food combining (more on this below), these types of diet rules can promote stress around mealtime and potentially play a role in the development of disordered eating habits.

Understanding the Digestive Process

In order for us to debunk the principles of food combining, we first need to understand how digestion works. With the exception of underlying digestive issues or medical conditions, each step in our digestive system–from top to bottom–involves a variety of intricate processes for breaking down food without issue.

“Our body can’t digest different foods simultaneously”

On the contrary, our bodies trigger the release of the appropriate enzymes in our mouth, stomach, and small intestine as needed to break down many foods simultaneously. These include:

  • Amylase: carbohydrate-digesting enzyme secreted in the mouth (saliva) and small intestine
  • Protease: protein-digesting enzyme in stomach and small intestine
  • Lipase: fat-digesting enzyme that works in stomach and small intestine (and small amounts in the mouth)

Our bodies are are designed to multitask, meaning a mixture of these enzymes are prompted to release when we eat, since our meals are usually a mixture of macronutrients (carbs, fat, protein). The human body evolved on a diet of whole foods with a mixture of these components.

Additionally, even if we are consuming just one food at a time and effectively following a food combining rule, many foods contain a mixture of said macronutrients (carbs, fat, and/or protein) regardless. Such as nuts, legumes, and even meat.

“Eating certain foods alone eases digestion”

Eating melon by itself, for example, will be digested very quickly and is technically “easy” for the body to do (unless you have diabetes or insulin resistance, in which case, your pancreas will have trouble coping with the influx of sugar). But that’s besides the point. What I want to say here is that this food rule assumes it’s “difficult” for our body to digest a few foods together. As we already discussed, this isn’t true. Additionally, eating certain foods away from others (such as carbohydrates away from protein or fat), is a recipe for blood sugar disaster.

When we consume carbs or sweeter foods on their own, the sugars are broken down and rapidly absorbed into our bloodstream. The result is a lack of satiety, feelings of hunger soon after, and a spike in blood sugar with a subsequent crash (fatigue, cravings). Combining starch with protein and fat is not only completely fine, but an essential part of healthy eating habits because it ensures balanced blood sugar by slowing down the rate at which sugar is absorbed.

“Food combining prevents gas and bloating”

There absolutely are certain foods that can cause gas and bloating by means of fermentation. However, this occurs in our large intestine (colon) by the microbes that reside there. Whether or not you eat beans with rice, for example, or an apple with nut butter, the specific types of prebiotic fibres found in certain foods (including beans and apples) are fermented by our gut bacteria and can cause gas and bloating. For some people with IBS this is more intense due to an intolerance to FODMAPs.

That being said, there are other reasons why gas and bloating can occur, although they have little to do with the combination of foods eaten. For example, if we have low stomach acid, pancreatic insufficiency, or had our gallbladder removed, we can experience trouble with digesting foods. But in most cases, sitting down to eat while calm, chewing thoroughly, and not overeating are enough to avoid excess gas and bloating–yes, even if it’s starch that you’re eating with protein.

Food Combining Rules that Are Useful

Okay, I think we’ve sufficiently covered the basics of the food combining diet and whether or not it’s necessary. But before I go, I do want to shed some light on a few food combining “rules” that are, in fact, useful. These include:

  • Iron with Vitamin C: vitamin C helps aid the absorption of iron in the body, so consuming them together can be helpful. This looks like spinach with citrus fruits, lentils with sliced strawberries, or taking an iron supplement that contains vitamin C (if you’re iron deficient).
  • Fat and Fat-Soluble Vitamins: vitamins like A, D, E and K are all fat-soluble. This means they dissolve in fat, and as such, they’re more efficiently absorbed when eaten with a food containing fat. Beta carotene is another nutrient that’s better absorbed alongside fat. For example, sweet potatoes with a drizzle of olive oil, mango with nuts, and avocado with kale.
  • Carbs with Fat, Fibre & Protein: we already discussed this, but it’s worth mentioning here. Combining carbohydrate-rich foods (think rice, potatoes, oats) with fat, protein and also fibre, helps to slow the rate at which they’re digested so that there are no blood sugar spikes. For example, oatmeal with hemp seeds and peanut butter, apple with nut butter or a handful of trail mix, or potatoes with vegetables, beans or salmon.

The Bottom Line

There is currently insufficient viable research to support the principles and claims of food combining. To date, there has only been one study, a peer-reviewed randomized clinal trial, that was done on the food combining diet but it found no benefits of food combining that a balanced diet didn’t already provide.

I understand the desire to follow food rules. They give us a sense of purpose or that we’re doing something right for our bodies. But food combining is simply not something that we need to get worked up over. Instead, listen to your body. Become familiar with intuitive eating by learning to tune into hunger and satiety cues. Eat a balanced diet. I know a “balanced diet” sounds vague and unsexy, but it just means that you include a variety of healthy, colourful whole foods that contain those essential carbohydrates, proteins, and fats; and you eat things with a sense of moderation. This is enough to keep your body happy and healthy. And if you do have concerns about your health (for example, digestive issues), then get to the root of it with a qualified professional so that you can enjoy many combinations of foods without discomfort.

You can also learn more about my 4-week Digestive Wellness Program.

Questions, comments, or food combining experiences to share? I’d love to hear from you below.

by Meghan Livingstone


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  1. Anne

    Hi Meghan! This article is super helpful and very easy to digest the informations 😉 In my experience, if I don’t eat a meal with protein + starch + fibre + fat, I will ALWAYS have crazy cravings not so long after my meal. However, I find an element quite curious: you mentionned that the food combining rules are “rooted in Ayurvedic medicine”, but I followed a (beginners) course in Ayurvedic nutrition and it is recommanded to have a meal with protein + starch + fibre + fat. So I am a bit confused about that point. Anyways, I love when you do those type of articles and would love to read more in the future!

    • Meghan

      Hi Anne! Great question. Food combining does have some roots in Ayurveda, although an early version of the diet was created by physician William Howard Hay back in the 1920s, which resembles the food combining diet today. I just updated some information in the post about this. I’m glad to hear you notice the benefits of combining protein, carbs, fibre, and fat! It’s definitely important 🙂

  2. Francesca Donati

    Hi Meghan, lovely article. Indeed it’s very interesting what you discussed here. Many thanks. I have a weird, actually, super weird question for you.

    If I combine in the same meal a raw cruciferous veg with a cooked cruciferous veg (eg. Arugula and cooked broccoli) I’ll throw up everything within a few hours. It happened a few times before I Realized it was this wrong food combination. Do you have an idea of what this can be? I got really afraid of combining some foods after getting really sick… especially fruit with meals or like I said, raw veggies and cooked ones. Hopefully you can help. Ps. Explained that to my doctor too but So far nobody has been able to understand hwy.

  3. Natasha L

    Your explanation makes total sense and sounds well researched. I realize that I’ve intuitively learned to ALWAYS eat protein with starches or carbs (Like nut butter with apples or fish with potatoes or rice) because that is how my body feels the best and I avoid stomach troubles that way. It’s true our bodies know what we need!


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