Foods That Turn Into Sugar in Your Body
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Foods That Turn Into Sugar in Your Body

Foods That Turn Into Sugar in Your Body
Everyday Health
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Updated on July 31, 2025
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Your body breaks down all the food you eat into something smaller. Some foods turn into amino or fatty acids, while others turn into sugar.

It’s not the white sugar you might put into your coffee. It’s glucose, a sugar your body uses for energy.

While digestion is a complicated process that’s not totally black and white, carbohydrates, as a general rule, turn into sugars, while protein and fat do not.

How Carbohydrate Digestion Works

To understand how or why carbohydrates turn into sugar, you need to understand the digestion process.

Carbohydrates come in three major packages: sugars, starches, and fibers. Fiber isn’t digestible, which means it stays mostly in its full form, so the body doesn’t convert it into sugar.

When you eat carbohydrates in the form of sugar or starches, your body’s goal is to break them down into the simple sugar, glucose, which it can use for energy.

The body doesn’t really convert carbohydrates into glucose — they already contain the sugar in a more complex package. The body just breaks them down into smaller components so it can more easily grab and use the glucose for something else.

Think of it this way: You have a castle you built out of blocks, but now you want to use those blocks to build a car instead. In order to access the individual blocks, you have to tear down the castle so you can use the blocks to build something new. That’s how it works with carbohydrates. They always have the glucose there, but the body needs to figure out a way to access it.

So, when you eat sugars and starches, the body breaks them down using various enzymes, digestive juices, and muscle movements in the digestive tract.

 Eventually, they make their way into the blood as glucose, which is the simplest form of sugar.

The Role of Glucose

Once glucose is in your bloodstream, your body does three major things with it:

  • Uses what it needs for immediate energy
  • Takes some of what’s left over and converts it to glycogen (the storage form of glucose) in the liver and muscles until they reach capacity
  • Takes any glucose that remains and converts it into fat, which is stored in fat cells

Depending on the type and amount of carbohydrates you eat, your body may do one or all of these things.

If you haven’t eaten for a while and you eat only a small amount of carbohydrates, there may be only enough to supply you with immediate energy.

 If you eat a large sugar- or starch-rich meal shortly after another carbohydrate-rich meal, you may not need any glucose at the moment, so your body will store it as fat.

What About Protein and Fat?

Although protein and fat don’t significantly raise your blood sugar after eating, they can affect it to a very minimal degree.

Protein is made up of compounds called amino acids.

 When you eat protein-rich foods, your digestive system breaks them down into those individual amino acids and then uses those amino acids to make other proteins in the body. To understand this, you can refer back to the analogy about the blocks.
There are 20 amino acids, and most of them are kept in their natural form and used where they’re needed to build other proteins.

 The body can sometimes convert proteins into glucose through a process called gluconeogenesis.

 But this usually has only a mild effect on blood sugar levels.

Dietary fat has an even more minimal effect on blood sugar, according to the Joslin Diabetes Center.

 When you eat fat, the body breaks it down into fatty acids that move into the blood and carry out a variety of functions.

 
If you eat more than your body needs, they group together and form triglycerides, which can circulate in your blood and get stored in your fat cells, increasing your body fat percentage.

Although the body doesn’t turn fat into sugar, it can convert carbohydrates (or sugars) into fat. This means that, if you eat more carbohydrates than your body needs, there’s a chance the carbohydrates get turned into fat and stored in your body’s fat cells.

Foods That Turn Into Sugar

Now that you know how the body uses different types of foods, you’re probably looking for a list of foods that contain a lot of sugar and starch.

Keep in mind that, while the body breaks down all carbohydrates (except fiber) into sugar, the effect that a particular carbohydrate-rich food has on your blood sugar depends on the whole package.

For example, some carbohydrates, like white sugar, are highly processed and contain no fiber. These types of carbohydrates, known as simple carbohydrates, turn into glucose quicker and raise your blood sugar to a greater degree.

Other carbohydrates might contain sugar and starch but also a lot of fiber. Carbohydrates that fall into this category, known as complex carbohydrates, do turn into glucose, but the process is slower, so it doesn’t affect your blood sugar levels as much.

The Harvard T.H. Chan School of Public Health provides a list of high-carbohydrate foods that turn into sugar in your body.

 Those that become glucose the fastest include:
  • Potatoes
  • Refined breakfast cereals
  • Soda and fruit drinks
  • White sugar
  • White-flour pasta
  • Candy and desserts
  • White rice
  • Couscous

The Takeaway

  • Foods high in simple carbohydrates, like refined breakfast cereals and white rice, quickly turn into sugar when you eat them.
  • Being mindful of portion sizes and choosing mostly complex carbohydrates, like fiber, can help prevent or moderate blood sugar spikes and weight gain.
  • If you have diabetes or concerns about blood sugar regulation, talk to your healthcare provider for personalized advice.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Carbohydrates. Cleveland Clinic. March 8, 2024.
  2. Patricia JJ et al. Physiology, Digestion. StatPearls. September 12, 2022.
  3. Hantzidiamantis PJ et al. Physiology, Glucose. StatPearls. April 30, 2024.
  4. All About Carbs. Heart Research Institute.
  5. Effects of Carbs, Protein, and Fats on Glucose Levels. Beth Israel Lahey Health Joslin Diabetes Center. July 8, 2021.
  6. Amino Acids. Cleveland Clinic. December 22, 2024.
  7. Nakrani MN et al. Physiology, Glucose Metabolism. StatPearls. July 17, 2023.
  8. Quaye E et al. Energy Expenditure Due to Gluconeogenesis in Pathological Conditions of Insulin Resistance. American Journal of Physiology Endocrinology and Metabolism. December 1, 2021.
  9. Crowley R. What Do Fats Do in the Body? National Institute of General Medical Sciences. January 24, 2024.
  10. Fat: The Facts. National Health Service. April 14, 2023.
  11. Carbohydrates and Blood Sugar. Harvard T.H. Chan School of Public Health.
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Roxana Ehsani, RDN

Roxana Ehsani, RD

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Roxana Ehsani, RD, is a Miami-based licensed dietitian-nutritionist, board-certified specialist in sports dietetics, and media spokesperson, consultant, and content creator for food and nutrition brands. She is an adjunct instructor for sports nutrition at Virginia Tech in Blacksburg.

Ehsani appears as a food and nutrition expert for television stations across the nation and in national publications, including Runner's World, Women's Health, Glamour, and more, and is a contributing writer for EatingWell. She has a strong background in sports nutrition and has worked with professional, Olympic, collegiate, and high school teams and individual athletes, whom she sees through her private practice. 

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Lindsay Boyers is a holistic nutritionist with a Bachelor's degree in food and nutrition and a certificate in holistic nutrition consulting. She has a background in functional nutrition and is currently studying for her RD exam.

In addition to contributing to everydayhealth.com, she has 12 published books, including The Everything Guide to Gut Health, The Everything Guide to the Ketogenic Diet, and The Everything Guide to Intermittent Fasting.

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