Do fatty foods cause acid reflux?

This is part two of the ten part mythbuster series on acid reflux myths. If you missed part one the series, you can read it here. Today’s post dissects the question: do fatty foods cause acid reflux? I’ll present the conventional wisdom behind the myth, as well as what the research has to say. I’ll use the myth-buster scaling system of totally true, a little bit true, or not true at all.

So, fact or fiction: do fatty foods cause acid reflux.  Read on to find out!

Fat 101:

Fats are one of the three macronutrients in the diet along with protein and carbohydrates. Macronutrients indicate a nutrient that contributes calories and that we need a large quantity.

From a chemical standpoint, fats are made up of three fatty acids and one glycerol molecule.

fat moleculte

Fat contains 9 calories per gram, making it the most calorically dense of all the macronutrients. Conversely, carbohydrates and proteins provide 4 calories per gram. According to the USDA, the adult diet contains between 20 and 35% of the total calories from fat. This means that if you eat 2000 calories per day, you’ll end up consuming 44 to 78 grams of fat each day. 

There are different kinds of fat. Below is a list of fat types including unique features and specific examples. Keep in mind, an oil or fat source may contain many different types of fats, but the major fat type directs the “category.”

Fat Types- 

  • Saturated Fat
    • Fat molecules with no double bonds, making them tightly packed. Typically found as solid at room temperature. 
    • Found in butter, coconut oil, palm oil and animal meat
  • Monounsaturated Fat
    • Fat molecules with ONE double bond, making them less packed together and typically liquid at room temperature. These fats are also known as a heart-healthy fat. 
    • Found in olive oil, peanut oil, canola oil, safflower oil, and sesame oil
  • Polyunsaturated Fat
    • Fat molecules with more than one double bond, typically liquid at room temperature. These fats contain omega 3s and omega 6s, the two essential fats in the diet. 
    • Found in fatty fish, soybean oil, walnuts and flax
  • Trans Fat
    • These fats are naturally occurring and artificially created. Artificial trans fats are banned from the food system due to their harmful nature. 
    • Partially hydrogenated vegetable oils and margarines

With the exception of trans-fat, eating fat has many health benefits. Fats are required for proper absorption of fat soluble vitamins like A, D, E, and K. Fat is also necessary for the synthesis of cholesterol, which keeps the brain healthy, produces sex hormones, and keeps joints lubricated.

To learn more about saturated fat and heart disease, click here.

So, does eating fat impact acid reflux? And if so, does it matter what kind of fat we eat?

Conventional Wisdom About Fatty Foods & Acid Reflux

Conventional wisdom says that fatty, rich foods cause acid reflux along with foods like tomatoes, citrus, caffeine, alcohol, chocolate and spicy foods.

For example, WebMD indicates that eating a large, fatty meal (e.g a burger and fries) causes heartburn. The site explains that a high fat meal sits in your stomach longer, causing more stomach acid release. In addition, the stomach expands after a large meal, putting pressure on the LES (the valve between your stomach and esophagus). This pressure allows stomach acid to get through to the esophagus, causing heartburn and acid reflux.

While this logic makes sense, WebMD does not cite any studies that back this up.

Keep in mind that the example meal of a burger and fries is high in trans and saturated fats. A meal like salmon in olive oil is also high in fat, but the poly- and mono-unsaturated types, which may produce different findings.

The question remains: is it the fat content of foods that causes acid reflux? And if so, does the type of fat matter? Or, is it really the amount of food we eat?

Let’s see what the science has to say…

Scientific Review of Fatty Foods & Acid Reflux

Research studies on this topic show mixed results.

Some studies indicate that a low fat diet may be helpful for those with acid reflux. Others find that body weight in combination with a high fat, calorie dense diet are to blame for reflux. While other studies find no correlation!

While your body knows best when it comes to specific acid reflux triggers, let’s dive into some of these studies…

Research Review- 

A cross sectional study published in Gut, the official journal of the British Society of Gastroenterology, found that high saturated fat and cholesterol intake was correlated with GERD, but only in those with a BMI over 25 (classified as overweight). Additionally, a high fiber intake was linked with fewer incidences of GERD.

Another study found that being overweight, but not a high dietary fat intake, increased hospitalization (esophagitis or hiatal hernia) in those with GERD. This may be due to the fact that obesity is an independent risk factor for acid reflux.

A different study indicated that those with obesity are 2.5 times more likely to experience GERD than their peers who have a BMI <25.

Yet another review published in 2009 indicates mixed results on whether a high dietary fat intake leads to acid reflux and GERD. One of the studies indicates that high percentage of calories from fat (saturated fat and cholesterol) is associated with acid reflux. Another found no difference between a high fat and a low fat meal, though a higher caloric load increased esophageal exposure to stomach acid.

Key Takeaway-

While the research is inconclusive, the takeaway is that a high saturated (and likely trans-fat), high calorie intake, in addition to being overweight or obese may provoke more acid reflux. So, eating a high fat diet alone may not give you heartburn, but pairing that with obesity AND high calorie meals, it’s a good bet you could be reaching for the TUMs.

Mythbuster Rating:

Rating – A little bit true

The research indicates that for most people, a high fat diet probably doesn’t cause acid reflux, but more likely contributes to it when paired with other factors (being overweight or eating a lot in one sitting). Additionally, the research shows that the kind of fat we eat does matter. Most of the studies indicated high saturated fat as the culprit.


Acid reflux is complex and multifactorial. Acid reflux can be caused by various issues from too little stomach acid to obesity. Determining your triggers can feel confusing.

The good news is that you don’t have to do it alone! Schedule your free consult and find out the nutrition program that’s right for you. 




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