11 Things Sugar Does to Your Body

Updated: Oct. 06, 2020

Do you have a sweet tooth or live for your daily soda? You may change your habits after you hear what it's doing to your body.

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Too much sugar may shorten your lifespan

Let’s be clear: A treat every once in a while is perfectly okay. Healthy eating is more about patterns of eating over time, rather than a single holiday or even an occasional indulgence. That said, daily consumption of added sugar may have a pretty significant negative impact on health outcomes. A study published in the American Journal of Public Health found that drinking a 20-ounce, sugar-sweetened soda daily was associated with the equivalent of 4.6 years of cell aging, the same as smoking cigarettes—and this cell aging has previously been linked with a shorter human lifespan. The things that happen to your body when you stop eating sugar, on the other hand, are beneficial to your health.

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Sugar can spike your insulin

One of the immediate effects of sugar on the body is the release of more insulin, which regulates blood sugar. Soda is the worst culprit, says Vasanti Malik, a research scientist at the Harvard T.H. Chan School of Public Health. “Sugars in beverages are absorbed very quickly, which results in rapid increases in blood glucose and insulin,” she says. “Over time this can lead to insulin resistance [in which the body needs more and more insulin to be effective], and place an individual on a pathway to adverse metabolic health.” Naturally occurring sugars, as in fruit, don’t have the same negative effects because they’re paired with fiber, which helps slow absorption.

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Sugar may put you at risk for type 2 diabetes

If you have high blood sugar, you could be on the road to type 2 diabetes already. (We explain the link between sugar intake and diabetes here.) “Insulin resistance requires the pancreas to produce more insulin since tissues are not as sensitive to it,” says Ed Saltzman, MD, a scientist in the Energy Metabolism Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. “Over time, the pancreas can become fatigued by this excess production and stops being able to secrete adequate insulin. When this occurs, type 2 diabetes may develop.” Even if you’re not pouring sugar in your coffee, you could be consuming more added sugar than you think. (Here are some sneaky sources of added sugar.)

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Sugar makes you gain weight

Your body needs some sugar for energy, but the rest is stored as fat. Not shockingly, sugar’s relationship to weight gain affects your health. “In a number of studies, added sugars have been associated with weight gain and obesity, which in turn leads to increased risk of type 2 diabetes,” says Dr. Saltzman. Why this happens is complicated, but may have to do with low-grade inflammation caused by obesity as well as insulin resistance, he says. In addition, he points out, eating loads of added sugar has also been linked to increased waist circumference—belly fat. “That’s an independent risk factor for heart disease,” says Dr. Malik. (Learn what eating sugar does to your skin.)

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Sugar may increase your blood pressure and heart disease risk

Here’s how to have your most heart-healthy day: Cut the sugar.  “High intake of sugars has been associated with an increase in a type of blood lipid called very low-density lipoprotein (VLDL) that has been associated with risk for cardiovascular disease,” Dr. Saltzman says. Sugar may also decrease HDL, the “good” cholesterol that protects against heart problems, he says. Plus, get ready for high blood pressure. “Insulin resistance may cause hypertension by its effects on the kidney, on the structure and function of arteries, and possibly on centers in the brain that contribute to blood pressure control,” he says.

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Sugar may mess with your brain’s signals

While it’s not exactly the same as the drugs of addiction, research has shown that sugar is as addictive as caffeine and nicotine, according to research published in Frontiers in Psychiatry—and eating it may lead to cravings, an increased tolerance for sugary foods, and withdrawal if you stop. “Energy-dense, sweet-tasting foods may lead to reinforcement of consuming those foods in a part of the brain called the limbic system,” Dr. Saltzman says. “In essence, we are training our brains to like and to want these sweet-tasting foods, and this may lead to increased consumption.” Dr. Malik also says sugar may stimulate the pleasure centers of your brain, similar to the way drugs do. If you’re fast becoming a glucose junkie, try these surprising ways to kick your sugar addiction.

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Sugar can leave you still hungry

Because you’re not getting any real nutrients when you eat sugar, you may still feel hungry. Plus, with sweet drinks, “calories from sugar in liquid form are not thought to be satiating, and people are not able to fully account for the calories that were consumed in liquid form with a compensatory reduction in calories at subsequent meals,” Dr. Malik says. So, you may end up eating more calories overall.

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Sugar may make your brain suffer

Another reason to curb your sugar intake? The research is piling up that soda is bad for your brain, as are other added sugars. A study published in Nutrients concluded that a high-sugar and high-fat diet impaired a range of memory functions, including short-term memory.

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Sugar may lead to fatty liver disease

An unhealthy liver is just one of the many effects of sugar on the body, especially when it’s consumed in large amounts.  “Fructose is metabolized in the liver, and consuming too much can lead to the production of fat in the liver, which is another path to adverse metabolic health,” Dr. Malik says. About 30 to 40 percent of adults in the U.S. have non-alcoholic fatty liver disease, according to the National Institute of Diabetes and Digestive and Kidney Diseases, and your risk factors include obesity, prediabetes, and high cholesterol. If you’ve gone on a sugar jag, you can try these 9 tricks to reverse a sugar binge.

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Sugar rots your teeth

What your dentist told you when you were a kid is true. “Oral bacteria love sugar just like we do, and when they feast on it, acid gets released as a byproduct,” says Sanda Moldovan, DDS, a periodontist in Beverly Hills. “This acid attacks the enamel of the teeth and allows bacteria to penetrate into the deeper layer of the tooth structure, called dentin.” The more sugar you eat, the more acidic the mouth becomes and the faster cavities develop. Plus, sugar feeds yeast growth, which might make the corners of your mouth or tongue red. “This also comes with a velcro-like feeling, or sensitivity to spicy foods,” she says. The sugar link is also a reason why type 2 diabetes is one of the many diseases your teeth can reveal.

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Sugar may raise your risk of depression

Eating too much sugar could make your depression worse, according to a study on post-menopausal women in the American Journal of Clinical Nutrition. “I like to tell my patients there’s a truth to the saying, ‘You are what you eat,'” says psychologist Deborah Serani, PsyD, award-winning author of Depression in Later Life. “High levels of sugar in the form of simple carbohydrates leads to spikes and crashes in glucose levels, which can worsen mood, increase irritability, agitation, irregular sleeping, and increase inflammation.” Instead, munch on lean protein, complex carbs, and foods with omega-3s, folate, and B vitamins.

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So how much can you have?

Many foods have way more sugar than you realize. The USDA’s Dietary Guidelines say no more than 10 percent of your calories should come from added sugar—for a 2,000 calorie diet that’s 200. The American Heart Association is stricter, with a limit of 100 calories for women and 150 for men. “The term ‘added sugars’ indicates sugars that are added to processed and prepared foods, as well as sugars added at the time of consumption,” says Dr. Saltzman. “Most research focuses on these added sugars as potentially harmful.” For example, if you have a Milky Way, which contains 31 grams (124 calories) of added sugar, you’re practically at your limit already. Bottom line? Read nutrition labels to see how much you’re getting and then read up on the 40 sneaky names for sugar you may not recognize.