Is sugar bad for you? Can it really have a head-to-toe impact on the human body?
When we’re talking about added sugar, the answer is a resounding “yes.” We know that sugar impacts just about every organ system in the body … and not in a good way.
Let’s take a look at the top ways added sugar destroys your body and ways to cut down on your intake so you can avoid sugar addiction and the negative effects added sugar has on health.
Is sugar bad for you? Health effects
Yes, sugar can be bad for you, especially added sugar. When consumed in excess, added sugar can damage your body in multiple ways, from your heart to your waistline to your teeth.
This isn’t just about “empty calories.” Sugar exerts real effects on your metabolism, hormones and long-term health.
1. Ticker trouble
Most people blame dietary fat for heart disease, and while certain industrial, inflammatory fats like trans fats do cause harm, sugar often is the real culprit.
In 2014, researchers were able to scientifically show that ingesting too much added sugar could significantly increase your risk of dying from cardiovascular disease (CVD). In fact, people getting 17 percent to 21 percent of calories from added sugar faced a 38 percent higher risk of dying from cardiovascular disease compared to those who got just 8 percent of their calories from sugar.
The relative risk was more than double for those who consumed 21 percent or more of their calories from added sugar.
Lots of other research has confirmed the link between sugar consumption and heart disease risk since.
For instance, a 2020 study revealed “that a diet with a greater proportion of sugar increased CVD risk via negative changes in metabolic profiles including body weight, waist circumference and lipid parameters, whereas [low sugar] produced the positive effects. A restriction of sugar intake to lower than 10% energy intake is vital to reduce CVD risk.”
Another study found that “added sugars drive coronary heart disease via insulin resistance and hyperinsulinaemia,” while a study from 2023 found all types of sugar actually heighten the risk of heart disease.
Today, most U.S. adults consume an average of 17 teaspoons of added sugars a day. That’s way more than what the American Heart Association (AHA) recommends.
AHA recommends:
- No more than six teaspoons or 100 calories a day of sugar for most women
- No more than nine teaspoons or 150 calories a day for most men
- Limit added sugars to no more than 6 percent of calories per day
2. Fatty liver
Here’s another reason to reduce sugar intake. Non-alcoholic fatty liver disease is on the rise in the U.S., and guess what’s largely to blame? Sugar!
High fructose corn syrup hiding out in drinks and processed foods has been called a “weapon of mass destruction” by researchers.
Non-alcoholic fatty liver (NAFLD) occurs when fat builds up in the liver.
Tufts University researchers discovered people who drink one sugar-sweetened beverage a day face a higher risk of non-alcoholic fatty liver disease compared to those who steer clear of beverages containing added sugars. (They also have an increased risk of dementia and stroke.)
Further research published in Nutrients investigated how consumption of sugar-sweetened beverages and artificially sweetened beverages relates to NAFLD and nonalcoholic steatohepatitis in U.S. adults using data from a national health survey. After adjusting for diet and lifestyle factors, the authors found that both heavy intake of sugar-sweetened drinks and exclusive consumption of artificially sweetened beverages were significantly associated with higher odds of having NAFLD, suggesting that not only sugary beverages, but also diet drinks may be linked to greater risk of fatty liver disease.
Interestingly, the microbiome is at play, too.
You see, the microbiome serves as the interface between diet and the liver and modifies dietary effects. Scientists are actively investigating our guts’ role in non-alcoholic fatty liver disease.
What is clear? Drastically backing down on added sugar intake does seem to improve this disease to some extent.
3. Metabolic issues
Is sugar bad for you, particularly when it comes to the gut? You bet.
Knowing that the microorganisms that live in the gut actually act similarly to a metabolic “organ,” researchers now believe sugar changes the gut microbiota in a way that increases intestinal permeability, aka leaky gut symptoms.
Eliminating excess added sugar is a key part of any effective leaky gut treatment plan. Added sugar feeds yeast and bad bacteria that can damage the intestinal wall, creating a leaky gut.
This means the chronic, low-grade inflammation that sugar triggers can lead to the transfer of substances from the gut into the bloodstream. This can trigger obesity and other chronic metabolic diseases.
On a similar note, a December 2014 study found sugar-sweetened soda drinks may influence the development of metabolic diseases. Researchers determined soda drinkers had shorter telomeres, a sign of decreased longevity, and accelerated cell aging.
Another prospective cohort study followed more than 1,000 adults for about six years and measured changes in visceral adipose tissue (deep belly fat) using CT scans. It found that higher habitual intake of sugar-sweetened beverages was associated with greater increases in visceral fat volume over time, even after accounting for changes in body weight, whereas diet soda intake was not linked to significant changes in abdominal fat.
These results suggest that regular consumption of sugary drinks may promote accumulation of harmful visceral fat, a risk factor for metabolic disease.
4. Diabetes-prone body
A 2013 study published in the journal PLoS One found that for every 150 calories of sugar a person consumes a day (about the equivalent of a can of soda), that person increased her risk of type 2 diabetes by 1.1 percent. This increased risk held true even considering researchers adjusted for the other types of foods people eat (including meat, oils, cereals, high-fiber foods, etc.).
Researchers also found the impact of sugar on diabetes held true regardless of a sedentary lifestyle and alcohol use.
This is no surprise considering sugar has a direct impact on diabetes.
5. Number of cancers
Does sugar impact cancer risk? When the National Institutes of Health set out to investigate sugar’s link to 24 different cancers, it didn’t find tons of published research, noting more is needed, but its researchers were able to find some associations between different types of sugar and certain cancers.
For instance, added sugars increase the risk of esophageal cancer, while added fructose (think high fructose corn syrup dangers) appeared to increase the risk of cancer in the small intestine.
Other research has hinted at a connection between high intake of added sugars and colon cancer. This higher risk remained even after adjusting for other colon cancer risk facts like being overweight or obese or having diabetes.
Dietary sugar could also increase the risk of breast cancer tumors and metastasis to the lungs.
The University of Texas MD Anderson Cancer Center published a 2016 animal study finding high amounts of dietary sugar in the typical Western diet seem to affect an enzymatic signaling pathway known as 12-LOX (12-lipoxygenase) in a way that increases breast cancer risk.
“We found that sucrose intake in mice comparable to levels of Western diets led to increased tumor growth and metastasis, when compared to a non-sugar starch diet … Prior research has examined the role of sugar, especially glucose, and energy-based metabolic pathways in cancer development. However, the inflammatory cascade may be an alternative route of studying sugar-driven carcinogenesis that warrants further study,” said Peiying Yang, Ph.D., assistant professor of palliative, rehabilitation and integrative Medicine.
The researchers pinpointed fructose, a component of table sugar and high fructose corn syrup, as the responsible sugar facilitating lung metastasis in the breast tumors studies. Previous epidemiological studies have shown that dietary sugar intake has an impact on breast cancer development, with inflammation thought to play a role.
There has been further research conducted on humans as well.
For instance, a prospective cohort study from the PREDIMED trial followed more than 7,000 adults and found that greater intake of liquid sugars (such as those in sugary drinks and fruit juice) was associated with a higher risk of developing cancer and increased cancer-related mortality. For every five-gram increase in liquid sugar intake per day, the risk of cancer rose significantly.
Another large observational cohort study using data from around 77,000 adults in Sweden reported that higher consumption of added sugars, soft drinks and sweetened foods was positively linked with greater risk of pancreatic cancer over roughly seven years of follow-up, with multivariate hazard ratios of about 1.69 for the highest versus lowest sugar intake.
These studies provide evidence that diets high in added sugars, especially from sugary beverages, are associated with increased risks of certain cancers, possibly through mechanisms involving insulin resistance, inflammation and metabolic dysregulation.
6. Weight issues
Sugar, particularly from sugary drinks and processed foods, contributes directly to excess calorie intake without providing nutrients your body needs. Calories from sugar are often stored as fat if they aren’t used for energy, contributing to weight gain, a major risk factor for obesity, type 2 diabetes and other chronic diseases.
Moreover, consuming high amounts of added sugar can lead to spikes in blood sugar and insulin, hormones that influence appetite, fat storage and hunger signals. Thus, sugar consumption makes it easier to gain weight over time.
7. Tooth decay
Sugar isn’t just about calories; it affects your oral health too.
When sugar sticks to your teeth, the bacteria in your mouth feed on it and produce acid that erodes tooth enamel. Over time, this leads to cavities and tooth decay.
In a study of U.S. adults using National Health and Nutrition Examination Survey data, researchers found that higher amounts of sugar from sugar-sweetened beverages were significantly associated with a greater prevalence of untreated decay in permanent teeth. Adults who consumed about 46.8 grams or more of sugar daily from these drinks had a higher likelihood of untreated dental decay compared with those reporting no sugar from such beverages, and the number of decayed teeth increased with greater sugar intake.
In a cross-sectional study of Alaska Native Yup’ik children (ages 6 to 17), scientists used a hair-based biomarker to objectively measure added sugar intake and found that higher sugar intake was significantly associated with a greater proportion of carious (decayed) tooth surfaces. This study directly linked added sugars in the diet to increased evidence of tooth decay in a pediatric population.
This is why dentists emphasize limiting sugary foods and drinks. It’s not just for overall health, but to protect your smile and prevent painful dental issues.
Sugar ingredients to avoid
Added sugars can fall under all sorts of different names on ingredient labels. One rule of thumb to find these hidden sugars is that any ingredient ending in “ose” is a type of sugar.
Don’t be fooled by more natural-sounding names either. Sweeteners like cane juice, beet sugar, fruit juice, rice syrup and molasses are still types of sugar.
Check out their placement in the ingredients list, too. The higher up an ingredient is on the list, the more of it is included in a product.
Other names for added sugar include:
- Anhydrous dextrose
- Brown sugar
- Confectioner’s powdered sugar
- Corn syrup
- Corn syrup solids
- Dextrose
- Fructose
- High fructose corn syrup (HFCS)
- Invert sugar
- Lactose
- Malt syrup
- Maltose
- Molasses
- Nectars (for example, peach or pear nectar)
- Pancake syrup
- Raw sugar
- Sucrose
- Sugar
- White granulated sugar
How much sugar is OK to consume?
Not all sugar intake is created equal. Natural sugars found in whole foods like fruit and dairy come packaged with fiber, vitamins and nutrients. Added sugars, those added to foods during processing, are the main concern.
Recommended limits
How much sugar per day should you consume? Here’s what leading health authorities suggest:
AHA:
- Women and children: no more than 6 teaspoons (24 grams) of added sugar per day
- Men: No more than 9 teaspoons (36 grams) of added sugar per day
U.S. dietary guidelines:
- Previous guidelines recommended limiting added sugar to less than 10 percent of total daily calories
- Updated guidelines released in 2026 are even more strict with the recommendations, stating people should avoid or sharply limit all added sugars (with children recommended to avoid them completely until age 10), and no meal should contain more than 10 grams of added sugar.
Consuming more than these amounts regularly is linked with weight gain, heart disease, diabetes risk and more.
How to cut down on sugar intake
Cutting back doesn’t mean eliminating sweetness forever. It means making smarter choices.
Here are some ideas to help out:
- Read nutrition labels. Look for “added sugars” on food labels. Many foods sneak in sugar under different names, like corn syrup, cane juice, maltose, dextrose or sucrose.
- Swap sugary drinks for water or unsweetened tea. Sugary beverages (soda, sweetened coffee drinks, fruit drinks) are some of the largest sources of added sugar in the diet. Cutting these out can instantly lower your sugar intake.
- Choose whole foods. Opt for fruits, vegetables, nuts, whole grains and lean proteins. These naturally balanced foods fill you up without excess sugar or empty calories.
- Make small substitutions. Need a little sweetness? Try natural options like fresh fruit or small amounts of stevia or allulose. These sugar substitutes can satisfy a sweet tooth with fewer impacts on blood sugar.
- Prepare more meals at home. Restaurant and packaged foods often contain added sugars. Cooking at home gives you control over exactly what goes into your meals.
Frequently asked questions
Is all sugar bad for you?
Not all sugar is equally harmful. Natural sugars in whole foods like fruit are paired with fiber and nutrients and aren’t linked with the same health risks as added sugars found in ultra-processed foods and drinks.
Can sugar cause diabetes?
Excess added sugar doesn’t cause diabetes by itself, but diets high in added sugar are strongly linked with being overweight, insulin resistance and higher risk of type 2 diabetes.
Does sugar affect kids differently than adults?
Yes, children’s bodies and brains are still developing. Experts recommend lower amounts of added sugar for kids, especially under age 2, and limiting sugary beverages and snacks.
What about natural sweeteners like honey or maple syrup?
They’re still added sugars at the end of the day and contribute calories. While some may contain trace nutrients, they should still be consumed sparingly.
Can cutting sugar improve health quickly?
Many people notice better energy, fewer cravings, improved weight management and better blood sugar control within days to weeks of reducing added sugar.
Final thoughts
- Is sugar bad for you? Yes, indeed. Added sugar can significantly increase your risk of early death.
- Sugar impacts brain function, can cause non-alcoholic fatty liver disease and increases your risk of heart disease.
- Added sugars appear to increase the risk of breast cancer and metastasis to the lungs.
- There are dozens of names for added sugar on ingredient labels.
- Simply dialing back on processed foods and drinks can lower your sugar intake. It’s also a great weight loss tip for women.
- If you do use sugar, use less processed forms, but use them sparingly. Alternatively, use green stevia for sweetening purposes. Allulose is another alternative worth exploring.
- Getting enough high-quality protein, fiber and fermented foods can help you lose your sugar cravings over time.
