How does refined sugar impact health? Here’s what science has to say.

While enjoying the occasional bowl of ice cream may not be cause for concern, having too much sugar can lead to a myriad of health issues. From heart disease to cancer, here is what science has to say about the impact refined sugar has on your health.

Whether you enjoy biting into a crisp pear, savoring a gooey truffle, or cooking up a bowl of pasta, sugar can be found in almost everything you eat. This sweetener is well-loved by many, and since it’s prevalent in many foods and beverages, you may not have thought twice about how this can affect your health.

While sugar can be enjoyed in small amounts, consuming excess amounts of refined (or added) sugars over time takes a toll on your body. From inflammation to elevated blood sugar levels and weight gain, there are many negative side effects that come from a sugar-laden diet. 

Before exploring how sugar impacts health, let’s first discuss some key differences between natural and refined sugars.

white sugar, brown sugar, and sugar cubes in wooden bowls

Understanding sugar

Sugar is a soluble carbohydrate that your body converts into glucose and uses for energy. There are different types of sugar (such as dextrose, fructose, galactose, glucose, lactose, maltose, and sucrose) which can be classified as either natural or refined sugars. However, not all sugar is created equal, as the effect it has on your body depends on what type you’re eating.

Natural sugar

As the name suggests, these sugars occur naturally in fruit (fructose) and dairy products (lactose). Thanks to the fiber and protein present in these foods, the natural sugars are digested and absorbed into the bloodstream at a slower rate, thus providing a steady supply of energy to your cells. They also contain other essential nutrients, like vitamins, minerals, and antioxidants, that are needed for energy metabolism, immune function, cell health, and more. Moreover, a diet rich in fruits and vegetables can help reduce the risk of chronic diseases, such as diabetes, heart disease, and some cancers.

Refined sugar

This type of sugar is processed from sugar cane or sugar beets and is typically found as sucrose (a combination of glucose and fructose). Unlike naturally occurring sugars in whole foods that are typically paired with fiber, your body rapidly breaks down refined sugars causing insulin and blood sugar levels to spike. Additionally, refined sugars contribute a large number of calories but have little nutritional value otherwise [


]. Diets high in refined (or added) sugars can increase your risk of diabetes, obesity, heart disease, cancer, and cognitive decline. 

There is no nutritional need nor benefit from added sugars, therefore the American Heart Association recommends limiting added sugars to no more than 6% of calories/day [


]. This can equate to:

  • Men: No more than 150 calories/day (36 g or 9 teaspoons)

  • Women and children aged 2+: No more than 100 calories/day (25 g or 6 teaspoons)

  • Children under 2: Not recommended to consume added sugars

How does sugar impact your health?

According to the Dietary Guidelines, the average American consumes 270 calories (or 17 teaspoons) of sugar/day, which is significantly higher than the recommended amounts [


]. This surplus is a risk factor for many chronic diseases. Here are some ways that excess sugar consumption can negatively impact your health [



Increased risk of heart disease

Heart disease is one of the leading causes of death worldwide and can stem from health issues (such as atherosclerosis, diabetes, inflammation, and elevated blood pressure levels) caused by poor diet and lifestyle choices [




]. Thus, a sugar-laden diet may spell bad news for your ticker, as excess amounts can raise blood sugar levels, inflammation, and blood pressure, all of which are biomarkers for heart disease. Moreover, studies found that those who consumed 17-21% of calories from added sugar increased their risk of dying from heart disease by 38% when compared to those who ate less added sugar [





Reduce your risk of heart disease with

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on how to boost HDL cholesterol. 

Decreased brain health

Studies have found that excess sugar consumption can lead to overall cognitive decline, impaired memory, and an increased risk of dementia [


]. Refined sugar has also been linked to mental health, as research suggests that those who consumed high intakes of added sugar were more likely to develop depression compared to those who had a lower intake [







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Increased cancer risk

Foods that are processed and high in added sugars have been shown to increase the risk of cancer. These refined carbohydrates tend to spike insulin levels and are associated with diabetes, weight gain, and cancer. Since insulin is linked to stimulating cell division, it is thought a high-sugar diet may promote the growth of cancer by increasing cell production and reducing cell death [


]. Moreover, inflammation increases with blood sugar and insulin fluctuations, which is associated with breast, prostate, and colorectal cancers [





Learn more about foods associated with increased cancer risk



Weight gain

Eating too much added sugar can negatively affect your weight. Since many sugary foods and drinks are high in calories and little else, consuming too many of these products over time can spell disaster on the scale [


]. Moreover, sugar intake also disrupts leptin production (a hormone that regulates hunger), which can increase your desire for food and contribute to weight gain [





Sugar isn’t the only thing that affects the number on the scale. Read more about how

stress levels


sleep deprivation

play a role in weight gain.

Increased risk of type 2 diabetes

While lifestyle, exercise levels, and genetics impact your risk of developing type 2 diabetes, your dietary choices (including sugar consumption) also play a role. Research has found that those who regularly drink sugar-sweetened beverages have a 25% greater risk of developing type 2 diabetes [


]. This could be due to the fact that fructose impacts your liver and promotes inflammation, localized insulin resistance, and abnormal insulin production [



assorted berries in a white bowl

How to limit your sugar intake

Cutting back on refined sugar may be challenging at first, but it gets easier over time. Here are some ways you can reduce your added sugar consumption.

  • Add fruit. Instead of adding sugar to cereal or oatmeal, try adding fruit instead of sugar. This will provide added flavor and nutrition while satisfying your sweet tooth.

  • Be consistent. Small changes add up over time, especially when it comes to sugar intake. Try cutting back on the sugar you add to cereal, pancakes, or coffee, and slowly continue to reduce the amount gradually. 

  • Limit sugar-laden drinks. Liquid sugar can be found in smoothies, fruit juices, energy drinks, or even milk, so it’s best to limit these items. Water is best, but if you want something else to drink, fruit-infused water or seltzer with a squeeze of fresh citrus are other healthful choices.

  • Choose more whole foods. Whole foods like fruits, vegetables, whole grains, and legumes haven’t been processed, so they are free of additives and other preservatives (such as refined sugar). By keeping these items in your kitchen, it may be easier to cut back on high-sugar foods.

  • Check the ingredient list. Food manufacturers add refined sugars for flavor, texture, color, and even to extend shelf-life, which means that added sugars may be present in unexpected products. It’s estimated that 75% of packaged foods contain added sweeteners (such as brown sugar, corn sweetener, high fructose corn syrup, honey, malt syrup, molasses, and turbinado sugar), so be mindful of this when food shopping [




Though sugar can be enjoyed in small amounts, excessive consumption of refined sugar can have serious health consequences, including weight gain and chronic inflammation, which can increase your risk for heart disease, cancer, cognitive decline, and more. If you are trying to reduce your sugar intake, try adding fruit to your meals, limiting sugar-laden beverages, and choosing more fiber-rich whole foods. 

Disclaimer: The text, images, videos, and other media on this page are provided for informational purposes only and are not intended to treat, diagnose, or replace personalized medical care.  

Key takeaways

  • The American Heart Association recommends limiting refined sugar intake to no more than 6% of calories/day [



  • Diets rich in refined (or added) sugars can increase your risk of diabetes, obesity, heart disease, cancer, and cognitive decline. 

  • Excess amounts of added sugar can raise blood sugar levels, inflammation, and blood pressure, all of which are biomarkers for heart disease.

  • Insulin is linked to stimulating cell division, so a diet rich in added sugars may support the growth of cancer by increasing cell production and reducing cell death [



  • If you want to reduce your sugar intake, try adding fruit to your meals, limiting sugar-laden beverages, and choosing more whole foods.


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