11 Reasons Why Too Much Sugar Is Bad for You

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By: Jillian Kubala, MS, RD | September 26, 2022 | Amy Richter, RD, Nutrition

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Sugar is fine for you in small amounts, but too much can lead to weight gain, acne, type 2 diabetes, and can increase your risk of several serious medical conditions.

From marinara sauce to peanut butter, added sugar can be found in even the most unexpected products.

Many people rely on quick, processed foods for meals and snacks. Since these products often contain added sugar, it makes up a large proportion of their daily calorie intake.

In the United States, the average adult consumes an estimated 17 teaspoons of added sugar each day. That accounts for 14% of total calorie intake in adults following a 2,000-calorie diet.

Experts believe that sugar consumption is a major cause of obesity and many chronic diseases, such as type 2 diabetes.

That’s why dietary guidelines suggest limiting calories from added sugar to less than 10% per day.

Here are 11 reasons why eating too much sugar is bad for your health.

1. It Can Cause Weight Gain

Obesity rates are rising worldwide, and evidence suggests that added sugar — often from sugar-sweetened beverages — is a major contributor to obesity.

Sugar-sweetened drinks like sodas, juices, and sweet teas are loaded with fructose, a type of simple sugar.

Consuming fructose increases your hunger and desire for food more than glucose, the main type of sugar found in starchy foods.

Additionally, animal studies show that excessive fructose consumption may cause resistance to leptin, an important hormone that regulates hunger and tells your body to stop eating.

In other words, sugary beverages don’t curb your hunger, making it easy to quickly consume a high number of liquid calories. This can lead to weight gain.

Research shows that consuming sugary beverages is associated with weight gain and increased risk of type 2 diabetes.

Also, drinking a lot of sugar-sweetened beverages is linked to an increased amount of visceral fat, a kind of deep belly fat associated with conditions like diabetes and heart disease.

2. May Increase Your Risk of Heart Disease

High-sugar diets have been associated with an increased risk of many diseases, including heart disease, the number one cause of death worldwide.

Evidence suggests that high-sugar diets can lead to obesity and inflammation as well as high triglycerides, blood sugar, and blood pressure levels — all of which are risk factors for heart disease.

Additionally, consuming too much sugar, especially from sugar-sweetened drinks, has been linked to atherosclerosis, a disease characterized by fatty, artery-clogging deposits.

A study in over 25,877 adults found that individuals who consumed more added sugar had a greater risk of developing heart disease and coronary complications compared to individuals who consumed less added sugar.

Not only does increased sugar intake increase cardiovascular risk, but it can also increase risk of stroke.

In the same study, more than eight servings per week of sugar-sweetened beverages were associated with increased stroke risk (10).

Just one 12-ounce (473-ml) can of soda contains 39 grams of sugar, which equates to 8% of your daily calorie consumption, based on a 2,000-calorie diet (14).

This means that one sugary drink a day can bring you close to the recommended daily limit for added sugar.

3. Linked to Acne

A diet high in refined carbs, including sugary foods and drinks, has been associated with a higher risk of developing acne.

Foods with a higher glycemic index, such as processed sweets, raise your blood sugar more rapidly than foods with a lower glycemic index.

Consuming sugary foods can cause a spike in blood sugar and insulin levels, leading to increased androgen secretion, oil production, and inflammation — all of which play a role in acne development.

Evidence has shown that low-glycemic diets are associated with a reduced acne risk, while high-glycemic diets are linked to a higher acne risk.

For example, a study of 24,452 participants found that the consumption of fatty and sugary products, sugary beverages, and milk was associated with current acne in adults.

Additionally, many population studies have shown that rural communities that consume traditional, non-processed foods have much lower rates of acne compared to more urban, high-income areas where processed food is part of a standard diet.

These findings coincide with the theory that diets high in processed, sugar-laden foods contribute to the development of acne.

4. Increases Your Risk of Type 2 Diabetes

Diabetes is a leading cause of mortality and reduced life expectancy. Its prevalence has more than doubled over the past 30 years, and projections estimate its burden will continue to rise.

Excessive sugar consumption has been historically associated with an increased risk of diabetes.

While no study has proven that sugar consumption causes diabetes, there are strong connections.

Eating large amounts of sugar can indirectly raise diabetes risk by contributing to weight gain and increased body fat — both of which are risks for developing diabetes.

Obesity, which is often caused by excessive sugar consumption, is considered the strongest risk factor for diabetes.

What’s more, prolonged high-sugar consumption drives resistance to insulin, a hormone produced by the pancreas that regulates blood sugar levels.

Insulin resistance causes blood sugar levels to rise and strongly increases your risk of diabetes.

Additionally, research has found that people who drink sugar-sweetened beverages are more likely to develop diabetes.

A study including individuals who drank sugary beverages for over a 4-year period found that increased consumption of sugary beverages — including soft drinks and 100% fruit juice — is associated with a higher risk for type 2 diabetes (25).

5. May Increase Your Risk of Cancer

Eating excessive amounts of sugar may increase your risk of developing certain cancers.

First, a diet rich in sugary foods and beverages can lead to obesity, which significantly raises your risk of cancer.

Also, diets high in sugar increase inflammation in your body and may cause insulin resistance, both of which increase cancer risk.

A systematic review analyzing 37 prospective cohort studies found that in two of five studies on added sugar, a 60% – 95% increased cancer risk was observed with higher sugar intakes.

The same review found that in 8 of 15 studies on sugary foods and beverages, a 23% – 200% increased cancer risk was observed with greater sugary beverage consumption.

Other studies have found sugar intake to be linked to specific types of cancer.

A study in over 22,720 men spanning over 9 years found that increased sugar consumption from sugar-sweetened beverages was associated with a greater risk of prostate cancer.

Another study found that esophageal cancer was associated with increased consumption of sucrose, or table sugar, and sweetened desserts and beverages.

Research on the link between added sugar intake and cancer is ongoing, and more studies are needed to fully understand this complex relationship.

6. May Increase Your Risk of Depression

While a healthy diet can help improve your mood, a diet high in added sugar and processed foods may contribute to changes in mood and emotions.

It may even increase your chances of developing depression.

High sugar consumption has been linked to cognitive impairments, memory problems, and emotional disorders like anxiety and depression.

Researchers believe that chronic systemic inflammation, insulin resistance, and a disrupted dopaminergic reward signaling system — all of which can be caused by increased sugar consumption — may contribute to sugar’s detrimental impact on mental health.

A study following 8,000 people showed that men who consumed 67 grams or more of sugar per day were 23% more likely to develop depression than men who ate less than 40 grams per day.

Another study in over 69,000 women demonstrated that those with the highest intakes of added sugars had a significantly greater risk of depression, compared to those with the lowest intakes.

7. May Accelerate the Skin Aging Process

Wrinkles are a natural sign of skin aging. They appear eventually, regardless of your health.

However, poor food choices can worsen wrinkles and speed up the skin aging process.

Advanced glycation end products (AGEs) are compounds formed by reactions between sugar and protein in your body. They are suspected to play a key role in skin aging (37).

Consuming a diet high in refined carbs and sugar leads to the production of AGEs, which may cause your skin to age prematurely.

AGEs damage collagen and elastin, which are proteins that help the skin stretch and keep its youthful appearance.

When collagen and elastin become damaged, the skin loses its firmness and begins to sag.

More research is needed to fully understand the connection between sugar and skin changes in humans.

8. Can Increase Cellular Aging

Telomeres are structures found at the end of chromosomes, which are molecules that hold part or all of your genetic information.

Telomeres act as protective caps, preventing chromosomes from deteriorating or fusing together.

As you grow older, telomeres naturally shorten, which causes cells to age and malfunction.

Although the shortening of telomeres is a natural part of aging, certain lifestyle choices can speed up the process.

Consuming high amounts of sugar has been shown to accelerate telomere shortening, which increases cellular aging.

A pilot study on 61 preschool-aged children found that increased consumption of sugar-sweetened beverages was associated with decreased telomere length, signifying cellular aging.

9. Drains Your Energy

Foods high in added sugar quickly spike blood sugar and insulin levels, leading to increased energy.

However, this rise in energy levels is fleeting.

Products that are loaded with sugar but lacking in protein, fiber, or fat lead to a brief energy boost that’s quickly followed by a sharp drop in blood sugar, often referred to as a crash (42).

Having constant blood sugar swings can lead to major fluctuations in energy levels.

A meta-analysis examining sugar’s effect on mood found that carbohydrate consumption, especially sugar, lowers alertness within 60 minutes of consumption, and increases fatigue within 30 minutes after consumption (42).

To avoid this energy-draining cycle, choose carb sources that are low in added sugar and rich in fiber.

Pairing carbs with protein or fat is another great way to keep your blood sugar and energy levels stable.

For example, eating an apple along with a small handful of almonds is an excellent snack for prolonged, consistent energy levels.

10. Can Lead to Fatty Liver

A high intake of fructose has been consistently linked to an increased risk of fatty liver.

Fructose is a common type of sugar, with one major source being high fructose corn syrup (HFCS) used to sweeten soda, candy, baked goods, cereals, and more.

Unlike glucose and other types of sugar, which are taken up by many cells throughout the body, fructose is almost exclusively broken down by the liver.

In the liver, fructose is converted into energy or stored as glycogen.

However, the liver can only store so much glycogen before excess amounts are turned into fat.

Large amounts of added sugar in the form of fructose overload your liver, leading to nonalcoholic fatty liver disease (NAFLD), a condition characterized by excessive fat buildup in the liver.

An animal study found that feeding mice a high-fructose diet for long periods of time led to the deterioration of their intestinal barrier, liver inflammation, liver tumors, and signs of fatty livers compared to a control group.

The same study found that the same amount of fructose is more likely to lead to developing a fatty liver when consumed through beverages rather than food, and when consumed in a single setting compared to several doses spread over a longer amount of time.

A study in over 5,900 adults showed that people who drank sugar-sweetened beverages daily had a 56% higher risk of developing NAFLD, compared to people who did not.

11. Other Health Risks

Aside from the risks listed above, sugar can harm your body in countless other ways.

Research shows that too much added sugar can:

  • Increase kidney disease risk: Fructose can increase serum concentrations of urate, leading to the development of kidney disease. Consistently high blood sugar levels can also damage the delicate blood vessels in your kidneys, increasing the risk of kidney disease (49).
  • Negatively impact dental health: Eating too much sugar can cause cavities. Bacteria in your mouth feed on sugar and release acid byproducts, which cause tooth demineralization.
  • Increase the risk of developing gout: Gout is an inflammatory condition characterized by pain in the joints. Added sugars raise uric acid levels in the blood, increasing the risk of developing or worsening gout.
  • Accelerate cognitive decline: High-sugar diets can lead to impaired memory and have been linked to an increased risk of dementia, Alzheimer’s disease, and stroke.

Research on the impact of added sugar on health is ongoing, and new discoveries are constantly being made.

How to Reduce Your Sugar Intake

Excessive added sugar has many negative health effects.

Although consuming small amounts now and then is perfectly healthy, you should try to cut back on sugar whenever possible.

Fortunately, simply focusing on eating whole, unprocessed foods automatically decreases the amount of sugar in your diet.

Here are some tips on how to reduce your intake of added sugars:

  • Swap sodas, energy drinks, juices, and sweetened teas for water or unsweetened seltzer.
  • Drink your coffee black or use a natural alternative for a healthier option.
  • Sweeten plain yogurt with fresh or frozen berries instead of buying flavored, sugar-loaded yogurt.
  • Consume whole fruits instead of sugar-sweetened fruit smoothies.
  • Replace candy with a homemade trail mix of fruit, nuts, and a few dark chocolate chips.
  • Use olive oil and vinegar in place of sweet salad dressings like honey mustard.
  • Choose marinades, nut butter, ketchup, and marinara sauce with zero added sugars.
  • Look for cereals, granola, and granola bars with under 4 grams of sugar per serving.
  • Swap your morning cereal for a bowl of rolled oats topped with nut butter and fresh berries, or an omelet made with fresh greens.
  • Instead of jelly, slice fresh bananas onto your peanut butter sandwich.
  • Use natural nut butter in place of sweet spreads like Nutella.
  • Avoid alcoholic beverages that are sweetened with soda, juice, honey, sugar, or agave.
  • Shop the perimeter of the grocery store, focusing on fresh, whole ingredients.

In addition, keeping a food diary is an excellent way of becoming more aware of the main sources of sugar in your diet.

The best way to limit your added sugar intake is to prepare your own healthy meals at home and avoid buying foods and drinks that are high in added sugar.

Frequently asked questions

What is added sugar?

Added sugars are sugars that are added during the processing of foods, during preparation, or at the table.

For example, sucrose or dextrose added during food processing is an added sugar, as is honey used to sweeten tea at your kitchen table.

Fortunately, “added sugars” are listed separately on Nutrition Facts panels underneath the line for “total sugars,” making it easier to determine whether or not your food contains any added sugars.

What is considered a high-sugar food?

Foods that contain close to, or more than the recommended amounts, may be considered high in sugar.

Men should consume no more than 9 teaspoons (36 grams or 150 calories) of added sugar per day.

Women should consume no more than 6 teaspoons (25 grams or 150 calories).

Foods high in sugar include:

While some foods high in sugar may be obvious, many foods are surprisingly high in sugar.

The Bottom Line

Eating too much added sugar can have many negative health effects.

An excess of sweetened foods and beverages can lead to weight gain, blood sugar problems, and an increased risk of heart disease, among other dangerous conditions.

For these reasons, added sugar should be kept to a minimum whenever possible, which is easy when you follow a nutrient-dense diet based on whole foods.

If you need to cut added sugar from your diet, try some of the small changes listed above.

Before you know it, your sugar habit will be a thing of the past.



Originally published on Healthline September 26, 2022. Written by Jillian Kubala, MS, RD. Medically reviewed by Amy Richter, RD, Nutrition. Republished with permission.

Photo credit: Nicole Katharina Schober/EyeEm/Getty Images

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