Eating too much added sugar and other refined carbs is linked to inflammation in the body — which may lead to health problems. But eating more fiber may be a powerful way to reduce inflammation, with other lifestyle changes.

Inflammation is part of the body’s natural healing process.

During injury or infection, the body releases chemicals to help protect it and fight off any harmful organisms. This can cause redness, warmth and swelling.

Some foods, like sugar, can also cause inflammation in the body.

But this is not acute inflammation, like the type you’d get with an injury, which comes and goes quite quickly. It’s chronic.

And chronic low-grade inflammation can increase your risk of serious health problems, such as heart disease, obesity, diabetes, cancer, rheumatoid arthritis, and allergies, according to research in humans and animals (2, 3, 4, X, Y).

This article covers the role of sugar on inflammation in the body, and provides a few key lifestyle tips to quell chronic inflammation.

Research in animals has shown that a diet high in added sugar leads to obesity and chronic metabolic diseases, including fatty liver disease (5).

Human studies confirm there’s a link between added sugar consumption and higher inflammatory markers.

A study of 29 healthy people found that consuming only 40 grams of added sugar from just one 375-ml can of soda per day for 3 weeks led to increased risk factors for cardiovascular disease (6).

These included higher inflammatory markers and fasting glucose, and unfavorable changes in LDL cholesterol. Participants who drank the daily soda gained more weight over the study than those who didn’t, too.

Another study in people with overweight and obesity found that those who consumed one can of regular soda daily for 6 months had increased levels of uric acid by the end of the study, a trigger for inflammation and insulin resistance. Meanwhile, those who drank diet soda, milk, or water had no increase in uric acid levels (7).

Drinking other sugary drinks can spike inflammation levels, too.

One study found that people who consumed a 50-gram dose of fructose experienced a spike in inflammatory markers like C-reactive protein (CRP) just 30 minutes later. Furthermore, CRP remained high for over 2 hours (8).

Eating a diet rich in foods that have a higher glycemic index, including refined starches and refined sugars, has also been linked to increased markers of inflammation, as well as higher mortality from inflammation-related diseases in older people (10, 11).

But the effects can happen in younger people, too. Young and healthy participants in one study experienced increases in an inflammatory marker called Nf-kB after eating just 50 grams of refined carbs in the form of white bread (11).

Research shows that consuming fructose as an added sugar — mainly in fructose-containing sweeteners, sucrose, high fructose corn syrup, sugar-sweetened beverages, and food additives — has a dose-dependent impact on inflammation. This means the more you eat, the greater the inflammation in the body (42, W).

Why many studies focus on sugar-sweetened beverages

You might notice that a lot of studies look at the link between inflammation and sugar-sweetened beverages, not added sugar in general.

That may be because sugar-sweetened drinks are just easier to keep track of in research, according to experts (AA).

Observational studies in humans often measure sugar intake by asking people how many sugar-sweetened beverages they drink per day.

This is often easier to count than intake of added sugars in general, since they can come in many, many different forms.


Consuming too much added sugar and refined carbs is linked with elevated markers of inflammation in the body, as well as insulin resistance and weight gain.

Consuming excess added sugar and refined carbohydrates causes several changes in the body, which help explain why a diet high in sugar can lead to chronic, low-grade inflammation.

Excess production of AGEs

Advanced glycation end products (AGEs) are harmful compounds that form when protein or fat combine with sugar.

They form as a natural product of metabolism in your body, and you can also eat them in food — especially from food that’s been dry cooked and browned at high temperatures (A).

Eating high amounts of added sugars can cause more AGEs to be produced in your body (C).

And having a higher concentration of AGEs in your body leads to oxidative stress and inflammation (12).

There are many lifestyle choices you can make to keep your AGE levels low, but when it comes to sugar, experts recommend limiting your intake of refined carbs and high-fructose corn syrup, and keeping your fasting blood sugar less than about 90–100 mg/dL (A).

Increased gut permeability

A high-sugar diet may increase inflammation in your gut and lead to increased gut permeability, also known as “leaky gut.”

In one human study, researchers fed healthy participants a high-sugar diet and found the permeability of their small intestine increased as a result (E).

Animals studies have also shown that gut permeability increased when researchers fed animals high-sugar diets (5).

Researchers say this may happen because eating lots of sugar throws your gut microbiome out of balance.

They say a high sugar intake changes the types and amounts of different bacteria in your gut, leading to overgrowth of inflammation-causing bacteria. This inflammation, in turn, may alter gut mucosa and tissue integrity, increasing permeability of the intestinal wall (5, D, 13, O).

Altered fat metabolism in your blood

Scientists have found that high sugar intake changes blood fat metabolism in multiple ways that increase your risk of atherosclerosis, or hardened arteries, and cardiovascular disease (F).

For example, high intake of sugar, especially fructose, appears to slow the breakdown of VLDL, a type of cholesterol that’s harmful if levels build up. Some research has found that sugar intake may also moderately increase blood concentrations of LDL, a related type of “bad” cholesterol (F, G).

These blood fat changes may have harmful downstream effects on inflammation. For example, excess LDL cholesterol has been associated with higher levels of C-reactive protein (CRP), a marker of inflammation (6, 14).

Fat gain

Higher levels of body fat, especially belly fat, are associated with increased inflammation. Researchers believe this is due to inflammatory compounds that this specific type of fat secretes into the bloodstream (K).

A lot of research has shown that drinking sugar sweetened beverages is clearly linked to having a higher body weight or body mass index (BMI) — both indirect measures of body fat percentage (H).

One study followed 3,070 people for 25 years and found that those who reported consuming more added sugar and sugar-sweetened beverages had higher body fat, including fat around their abdominal organs and hearts, than those who consumed less (J).

It’s important to note that body fat isn’t bad. In fact, it’s essential. The optimal body fat range for you depends on your own genetic background, sex, age, activity level, and other factors.

And no body fat percentage number is enough to provide a complete picture of your health.


Excess consumption of added sugar and refined carbohydrates is linked to increased AGE production, gut permeability, unhealthy blood lipid changes, and weight gain. All of these factors can trigger chronic inflammation.

Observational studies in humans have linked high added sugar and refined carbohydrate intake to many chronic diseases, including heart disease, cancer, diabetes, obesity, and more.

Heart disease

Several studies have found a strong link between consuming sugary drinks and an increased risk of heart disease (16).

A study in more than 75,000 women found that those who consumed a diet high in foods with a high glycemic load (GL) had up to a 98% greater risk of heart disease compared with those who tended to consume foods with a lower GL (17).

GL is a measure of how quickly your body absorbs sugar from portions of food into your blood stream. The term is related to glycemic index (GI). Essentially, the higher the GL or GI, the faster your body absorbs the sugar, and the higher it may raise your blood sugar levels as a result (K).

In contrast, low GL and GI foods absorb slowly, so they reach your blood sugar at a slow rate, lowering the risk of blood sugar spikes (K).

We know that foods with a high GL/GI tend to be refined carbs or high in added sugars, like white bread, white rice, and glucose. A few whole foods also have a GL/GI, including baked potatoes (K, L).

Elevated blood sugar levels are a known risk factor for heart disease (CC).

And sugar consumption may increase other heart disease risk factors, too.

Studies have shown that high-sugar diets are linked with unhealthy changes in cholesterol, increased blood pressure, obesity, insulin resistance, and increased inflammatory markers. This has been studied particularly in people who drink a lot of sugar-sweetened beverages (16, 18, F, G).


The research on sugar and cancer is mixed.

Overall, a 2022 review of research found that excess sugar consumption higher than recommended dietary limits was linked to the development and progression of cancer in humans, regardless whether it contributed to obesity (N).

The review found that high-sucrose (table sugar) and high-fructose diets led to cancer in multiple ways, including by increasing inflammation (N).

Several studies show people who eat a lot of high glycemic load foods — including many refined carbs and foods high in added sugar, like sugar-sweetened beverages — may be at a greater risk of developing several kinds of cancer, though more research is needed (19, 20, 21, 22).

Interestingly, large-scale observational studies in people have found that drinking liquid sugar, like in soda and other sugar-sweetened beverages, seems to have a stronger link to cancer than eating sugar in solid food form (L).

One study found that when mice were fed high-sugar diets, they developed breast cancer, which then spread to other parts of the body (3).

Another study looking at the diets of over 35,000 women found that those who consumed the most sugary foods and drinks had double the risk of developing colon cancer, compared to those who consumed a diet with the least added sugar (20).

One review of research found that dietary sugar directly influenced the growth of endometrial and colon cancers (M).

Some experts believe that chronically high insulin levels, which can result from consuming too much sugar, may also play a role in cancer development (24).


Studies link the increased consumption of refined carbs, sugar-sweetened beverages, and corn syrup to type 2 diabetes (25, 26, 27, 28).

A large analysis including over 38,000 people found that just one serving of sugary drinks daily was associated with an 18% greater risk of developing type 2 diabetes (26).

Another study found that increasing corn syrup intake was strongly associated with diabetes. On the other hand, fiber intake helped protect against the development of diabetes (27).


Obesity is often referred to as a low-grade inflammatory disease. Eating too much added sugar, including sugar-sweetened beverages, is linked to weight gain and obesity (29, 30, O, U).

Experts suggest that modern diets, which are often high in refined carbs and added sugar, can lead to an imbalance in gut bacteria. They believe this may partly explain the development of obesity (9, O).

A review of 88 observational studies found that a higher intake of sugary soda was associated with greater calorie intake, higher body weight, and lower intake of other important nutrients (31).

One study in mice found that a diet high in sugar counteracted the anti-inflammatory effects of fish oil and promoted obesity (4).

Other diseases

A high intake of added sugar and refined carbs has been linked to the development of other diseases, such as liver disease, inflammatory bowel disease, mental decline, arthritis and others. However, the evidence is moderate or lower quality, and more research is needed (2, 32, 33, 34, P).

In particular, excess fructose consumption has been linked to non-alcoholic fatty liver disease.

How this happens isn’t fully understood, but it may be due to a mix of increased gut permeability, bacterial imbalance in the gut, and ongoing low-grade inflammation (35).


Observational studies have linked excess added sugar consumption to the development of several chronic diseases, such as diabetes, heart disease, obesity and cancer.

It’s important to note that there is a difference between added sugar and sugar that’s naturally found in whole foods.

Added sugar is removed from its original source and added to foods and drinks to serve as a sweetener or increase shelf life in some products (Q, R).

Added sugar is found mostly in processed foods and drinks, though table sugar (sucrose) is also considered an added sugar. Any kind of sugar that’s extracted from it’s original source and added to prepared food is an added sugar — even if it’s still in its natural form, like honey (R).

There are many names for added sugar that you might see on the ingredients list of a prepared food, including high-fructose corn syrup (HFCS), sucrose, fructose, glucose, corn sugar, honey, maple syrup, agave syrup, coconut sugar, and many more.

Among US adults, around 13% of total calories come from added sugar. This is high, considering that government guidelines advise that no more than 5% to 15% of calories should come from both solid fats and added sugar (S, 36).

Excess amounts of added sugar and refined carbs have been linked to inflammation (6, 9, 10).

However, sugar that’s naturally present in whole foods has not been linked to inflammation. In fact, many whole foods containing natural sugars, such as fruits, may be anti-inflammatory (37).

Sugars naturally occurring in foods include fructose in fruit and lactose in milk and dairy products.

Consuming natural sugars as part of whole foods should not be any cause for concern. That’s because they act very differently than added sugar when consumed and digested in the body (T).

You eat natural sugar in whole foods along with other nutrients in the same bite, such as protein and fiber, which cause natural sugars to be absorbed slowly. The steady absorption of sugar from whole foods prevents blood sugar spikes.

A diet high in whole foods like fruit, vegetables, and whole grains can have other health benefits, too. There is no need to limit or avoid whole foods if you’re trying to reduce your risk of disease (38, 39, 40, AA).


Added sugar, which is removed from its original source and added to foods and drinks, is associated with inflammation. Natural sugar eaten as part of whole foods, like the fructose in fruit, is not.

The good news is that you may be able to reduce inflammation levels by making dietary changes.

Certain lifestyle changes, such as reducing your intake of sugary and ultra-processed foods, can lead to lower inflammation levels in the body (41, V).

In addition, a sedentary lifestyle, smoking, and high stress levels have also been associated with chronic low-grade inflammation — so making changes on these fronts may help as well (43, 44, 45).

And of course, exercise helps too. Regular physical activity has been shown to reduce belly fat and inflammatory markers in humans (46).

Focus on fiber

Fiber may be your most important tool for reducing inflammation. Maybe even more important than reducing sugar.

The research on anti-inflammatory diets tends to focus more on the benefits of fiber and a high-fiber diet than the harmfulness of sugar.

When you’re thinking about eating an anti-inflammatory diet, it may be helpful to shift your focus to increasing your fiber, while still keeping your intake of sugar and refined carbs in mind.

That’s because eating lots of fiber is clearly associated with reduced chronic inflammation.

Research has shown that diets high in fiber reduce inflammation in many different chronic conditions, including cardiovascular disease, type 2 diabetes, inflammatory bowel disease (IBD), rheumatoid arthritis, and depression (V, W, Z, BB).

Researchers believe fiber does this because it feeds beneficial bacteria in your gut that help reduce inflammation, with beneficial effects throughout the body (V, W, Z, BB).

When it comes to reducing or preventing chronic inflammation, focusing on eating more fiber may be your best bet, rather than simply trying to reduce your sugar and refined carb intake on their own.

Anti-inflammatory lifestyle tips

Here are some everyday tips to help reduce inflammation:

  • Eat more fruits and vegetables: Fruits and vegetables contain fiber, antioxidants, vitamins and minerals, which can protect against and reduce inflammation in the body.
  • Choose whole-grain carbs: These include oats, whole-grain pasta, brown rice, quinoa, and barley. They have lots of fiber and antioxidants, which can help control blood sugar and protect against inflammation.
  • Limit ultra-processed foods and sugar-sweetened drinks: By reducing or eliminating these, you’ll naturally exclude key sources of added sugar, like soda, cakes, cookies, and candy.
  • Read food labels: If you are unsure about certain products, get into the habit of reading food labels. Look out for ingredients like sucrose, glucose, high-fructose corn syrup, maltose and dextrose. Even better — focus on eating whole foods that don’t have food labels.
  • Eat lots of antioxidant-rich foods: Fill your plate with foods rich in antioxidants, which naturally help counteract inflammation. These include fruits, veggies, nuts, seeds, oily fish, tea, coffee, and olive oil.
  • Keep active: Regular physical activity, including both aerobic and resistance exercise, can help protect against weight gain and inflammation.
  • Manage stress levels: Learning to manage stress levels through relaxation techniques or even exercise can help reduce inflammation.
  • Consider fasting: A lot of research has shown that various types of fasting, including intermittent fasting, are associated with reductions in inflammation in humans and animal studies (V).

Replacing foods and drinks high in added sugar and refined carbohydrates may help lower inflammatory markers. Including whole foods in your diet can also help fight inflammation because they’re naturally packed with fiber, antioxidants, and other important nutrients to help you thrive.

The evidence suggests that eating too much added sugar and too many refined carbs causes inflammation in your body.

The inflammation caused by poor dietary habits may be linked to several health problems, such as heart disease, diabetes, liver disease, and cancer.

There are several things you can do to help fight inflammation, including eating lots of whole foods and fiber, exercising regularly, and effectively managing your stress levels.

Furthermore, cut down on ultra-processed foods and sugar-sweetened drinks, choose whole foods, and limit your intake of added sugar and refined carbohydrates.

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