Is An Apple A Fast Digesting Carb? (A Dietitian Answers)

If you’re looking for a pre-workout snack to fuel your training session or a snack to hold you over in the afternoon, then you may be wondering if apples are a good choice; but this depends on how quickly they digest.

A whole unpeeled apple is a slow-digesting carb. While it contains simple sugars, it also contains fiber (especially in the skin) which is the nutrient that slows down the digestion process, leading to a slower rise in blood sugar levels. This means the glycemic index (GI) is relatively low, at around 40. 

Knowing how quickly apples digest can help you decide when is the best time to consume these foods, which can assist you in reaching your goal.

Key Takeaways

• Apples are made up of sugar and fiber; because of the fiber content, they probably take around 1 hour to digest and are not a fast-acting energy source.
  
• Different types of apples can have slightly different fiber content (per 100g, Granny Smith and Pink Lady have 2.5-3g compared to Honeycrisp at 1.7g).
   
• You can make apples a faster-digesting carb by cooking, peeling, or blending them, making them easier to digest.

Understanding the Glycemic Index

The glycemic index (GI) is a scoring system used to understand how quickly carbohydrates in food affect blood glucose (sugar). It categorizes foods on a scale of 0 to 100 based on how much they raise blood sugar levels, with a higher score indicating a rapid spike in blood sugar. 

The rate at which carbs raise blood sugars is related to how quickly they digest and absorb. 

Fast-digesting carbs raise blood sugar more quickly, produce fast-acting energy, and have a higher GI rating. 

Slow-digesting carbs cause a slow and steady release of sugar into the bloodstream, more stable energy, and a low GI rating.

Foods with a low GI (1-55) and medium GI (56-69) are slower-digesting because they take longer to break down, as they contain more fiber and starch and less simple sugars.

Conversely, foods with a high GI (70-100) consist mainly of simple sugars and/or refined carbohydrates and are broken down and absorbed at a faster rate.

Having said this, there are also other points to mention when talking about the digestion of carbs, such as the number of carbs in a food and whether such food contains fiber, protein, and fat. These factors can also impact the rate at which carbohydrates are digested.

How Long Does It Take Apple To Digest?

According to research that looked at the digestion of 350g of whole apples in one sitting, it takes around 65 minutes for this quantity of apples to leave the stomach. Based on this, a medium-sized apple (80-100g) would probably take less than 65 minutes to leave the stomach, considering the smaller quantity.

It is hard to pinpoint exactly how fast apples digest because it also depends on ripeness, variety, and how it is prepared or eaten.

The ripeness of an apple impacts the digestion speed, as a ripe apple will digest more easily than an unripe apple because of the higher fiber content and lower sugar content in unripe apples.

An apple will also digest more quickly if it’s peeled because most of the fiber is in the skin of the apple.

Lastly, eating an apple with foods high in fiber, fat, and protein (like chicken) slows down the digestive process because there is a larger volume of food to digest and these nutrients (fiber, fat, and protein) digest more slowly than sugar.

For example, if you add a chopped apple with a bowl of oatmeal and nuts, the food particles will take longer to break down, therefore delaying sugar absorption.

• Related article: What Are Fast Digesting Foods? 10 Examples & When to Eat

Is Apple A Complex or Simple Carb?

It’s tricky to classify apples as simple or complex carbs since they contain both. 

Simple carbs mainly consist of simple sugar molecules and are low in fiber and resistant starch, making them easy to digest and quick to absorb. Think fruit juice.

Complex carbs are made up of larger molecules that mainly contain resistant starch and fiber. This leads to slower digestion and energy absorption, often resulting in longer-lasting satiety. Think whole wheat bread.

An 80-100 gram apple with the peel intact contains about 2-3 grams of fiber, which makes it a good source of fiber and therefore slower to digest.

This is why it is placed in the low GI category, at 40.

So, how does an apple compare to other types of carbs?

The following table shows a few different types of carb foods with their GI score, according to the International tables of glycemic index values.

*Remember that low GI foods are 1-55, medium GI foods are 56-69, and high GI foods are 70+. 

As you can tell, an apple is slower digesting than many carb foods, such as white bread, ripe banana, flavored instant oats, and pineapple, which have more sugar than apples; but faster digesting than barley and beans, which are even higher in fiber than apples.

Types of Apples: Ranking From Fastest To Slowest Digesting

Most of the evidence around the GI of apples does not distinguish between different varieties, as seen in the International tables of glycemic index values.

So, it is impossible to rank different types of apples based on their GI. However, it is possible to rank them based on minor differences in nutrient composition, such as fiber content (which we know slows down digestion).

The following table shows a few different types of apples with their fiber content (per 100 grams), according to the U.S. Department of Agriculture Food Data Central.

Pink Lady apples have the highest fiber content, whereas Honeycrisp has the lowest content.

Based on these differences, it’s safe to assume that Pink Lady Apples likely digest the slowest, and Honeycrisp varieties likely digest the fastest.

These minor differences in fiber content probably occur because some apples have thicker skin than others, and as the skin of apples is where most of the fiber is, this might contribute to slower digestion and a lower GI rating.

• Related article: 17 Best High-Fiber Low-Calorie Foods

Benefits of Eating A Slow Digesting Carb Like Apples

1. Steady Rise In Blood Sugars

A whole apple with the peel intact is a great slow-digesting carb source that can offer a steady rise in blood sugars, providing more stable and sustainable energy.

Having more of these types of foods will help to balance blood sugar levels, preventing spikes and crashes in energy levels.  

These types of carbs are better for people who are trying to lose weight or those who have problems with managing blood glucose (such as people with diabetes).

To help apples stay with you a bit longer and delay hunger, they are best paired with a protein and/or fat source, like peanut butter.

2. Nutritious 

Slow-digesting fruits like apples are a good source of fiber and vitamins and minerals (if you do not remove the skin) that are essential for your overall health. 

“Apples are a familiar fruit, available at low prices year-round, and highly valued for their richness in dietary fiber, vitamin C, potassium, and other nutrients. An apple is rich in organic acids, such as citric acid, and dietary fiber, which slows down the rate of gastric emptying”

– Yutaka Inoue, MDPI Foods Journal

They are particularly high in vitamin C and polyphenols, which are thought to reduce the risk of diseases, such as cardiovascular disease and some forms of cancer.

In addition, these fruits are made up of naturally occurring fruit sugars too, so they can be a healthier choice than food containing added sugar.

Drawbacks of Eating A Slow Digesting Carb Like Apple

1. Not A Quick Energy Source

One drawback of choosing an apple over other fast-digesting fruit is that it will not provide you with fast-acting energy.  

If you are feeling low on energy and need a quick boost or need a carb immediately before or after exercise to fuel your workout and encourage faster recovery, then you shouldn’t reach for an apple. Instead, use a fast-digesting carb like a ripe/overripe banana.

2. Potential Gut Discomfort 

Apples have the potential to cause gut discomfort because they contain prebiotic fiber that feeds your gut bacteria. Though healthy for you, if consumed in larger amounts, they do have the potential to cause gas and bloating.  

If you feel you have a sensitive tummy, having fiber-rich foods in smaller portions will allow your digestive system to adapt gradually to fiber and reduce the risk of discomfort.

When Should You Eat Apple?

You can eat an apple at any point in the day; however, there are certain situations when reaching for an apple is more advantageous.

• 1 hour before a workout, eaten on its own. However, it is not ideal immediately before (15-30 minutes before) or during exercise, as it’s a slow-release energy source.
  
• 2 hours before exercise paired with carbs and protein.

• As a convenient and healthy snack in between meals. You can eat them on their own or pair them with a source of protein, such as yogurt, or nuts, to make it more complete and filling.

• If you are hungry because you have not eaten in a long time, having an apple with you can prevent you from getting caught off guard and resorting to lower-quality options.

How To Make Apples Digest Faster or Slower

1. Cook or Blend Them

Cooking apples or blending them helps to break down the fiber that apples naturally contain, making them quicker to digest. 

Part of the digestion process is chewing and breaking down your food into a pulp, so by cooking and blending apples, you no longer have to put in as much work to break them down, leading to faster digestion.

Therefore, if you blend an apple to make a cup of fresh apple juice, or if you cook and puree an apple to make applesauce, then they will become a fast-digesting carb.

For example, you could try making applesauce, apple juice, or a smoothie if you want a faster-digesting carb.

2. Combine Them With Other Foods

Combining apples with foods containing protein, fats, and additional fiber will slow down the digestion rate. 

If you want a faster rate of digestion, then have them on their own; but, if you want them to digest more slowly to hold you over for longer then pair them with other nutrients.

For example, you could have a charcuterie plate with apples, cheese, and deli meat, or dip them in peanut butter to slow down their digestion.

3. Choose If You Want Them Peeled on Unpeeled

The skin of the apple contains a high amount of fiber (as well as other nutrients), which makes apples digest slower. If you want apples to digest faster, peel the skin off before eating them.

References

Bertoia, M. L., Mukamal, K. J., Cahill, L. E., Hou, T., Ludwig, D. S., Mozaffarian, D., Willett, W. C., Hu, F. B., & Rimm, E. B. (2015). Changes in Intake of Fruits and Vegetables and Weight Change in United States Men and Women Followed for Up to 24 Years: Analysis from Three Prospective Cohort Studies. PLOS Medicine, September 22, 2015. https://doi.org/10.1371/journal.pmed.1001878

Inoue, Y., Cormanes, L., Yoshimura, K., Sano, A., Hori, Y., Suzuki, R., & Kanamoto, I. (2022). Effect of Apple Consumption on Postprandial Blood Glucose Levels in Normal Glucose Tolerance People versus Those with Impaired Glucose Tolerance. Foods (Basel, Switzerland), 11(12), 1803. https://doi.org/10.3390/foods11121803

Wojdyło, A., Oszmiański, J., & Laskowski, P. (2008). Polyphenolic Compounds and Antioxidant Activity of New and Old Apple Varieties. Journal of Agricultural and Food Chemistry, 56(15), 6520–6530. https://doi.org/10.1021/jf800510j