Added sugars should be kept to a minimum, nutrition experts agree. Unlike the sugar that occurs naturally in fruit, dairy products, and other whole foods, added sugars are, as the name implies, added to foods by manufacturers or consumers to make them sweeter. The 2015–2020 Dietary Guidelines for Americans recommends keeping added sugar intake to no more than 10 percent of total calories. On a 2,000-calorie diet, that’s 200 calories (50 grams or about 12 teaspoons). The average American, however, consumes about 17 teaspoons per day.
Because of added sugar’s link to obesity, cavities, and chronic diseases such as diabetes and heart disease, some organizations suggest even stricter limits. The World Health Organization, for instance, recommends keeping added sugar to less than 5 percent of total calories. The American Heart Association (AHA) advises "limiting the amount of added sugars you consume to no more than half of your daily discretionary calories allowance." The AHA considers this 100 calories (6 teaspoons) for women and 150 calories (9 teaspoons) for men.
It can be tricky to avoid added sugar, considering more than two-thirds of packaged foods contain added sugar. There are some ways to tell if you’ve been consuming too much, though. Here’s a look at some of the common signs.
Constant cravings for sweets may mean you’re eating too much sugar
When it comes to trying to kick our sugar habit, we may be working against millions of years of evolutionary programming. In an interview with Business Insider, professors Richard Johnson and Daniel Lieberman explained that liking the taste of sugar was key to the survival of our ancestors. In addition to providing a quick burst of energy, the simple sugar fructose can be easily stored as body fat thanks to specific gene mutations. This gave sugar-loving early humans an advantage during periods of food scarcity. The problem is that we can’t just turn off these hardwired cravings now that we live in a world with almost limitless access to foods hundreds of times more sugary than anything our ancestors would have been able to find.
To make matters worse, many experts believe sugar is addictive. It doesn’t cause true physical dependency in the same way as certain drugs, but sugar appears to trigger the same reward centers of the brain that are stimulated during drug use. And at least in laboratory animals, sugar appears to be more addictive than cocaine. If you’re eating too much sugar, these cravings will become even more severe. "Ironically, the more sugar you eat, the more you crave it because over-consumption of sugar can lead to insulin resistance," Women’s Health Network explained.
Energy crashes and irritability result from eating too much sugar
Sugar provides a quick jolt of energy, but it can leave you feeling exhausted just as fast. Anyone who’s ever overdone it on the sweets is familiar with the infamous sugar crash. Sanford Health explained that these crashes occur when our bodies are flooded with tons of sugar and the pancreas must respond by pumping out lots of insulin. This sudden spike and then drop in blood glucose leaves us feeling tired, irritable, and shaky. To avoid these crashes, Sanford recommended eating fewer simple sugars and consuming them with fiber and protein to help slow absorption.
Nevertheless, not all experts agree with this explanation of sugar crashes. In an interview with WebMD, Dr. Robert H. Lustig presented a different hypothesis. He noted that while true hypoglycemia (defined as a blood sugar level below 60 mg/dL) can cause irritability and shakiness, the rebound from a typical sugar binge won’t drive blood sugar that low. Lustig instead argued that eating sugar causes a release of the feel-good neurotransmitter dopamine, and it’s the sudden drop in dopamine once the sugar is gone that leads to the characteristic symptoms of a sugar crash. In this way, he likened a sugar crash to withdrawal.
Eating too much sugar can lead to weight gain
Eating large amounts of sugar contributes to weight gain in several ways. At the most basic level, sugar contains calories — four per gram. Based on the energy balance model of weight control, if you eat more calories than you expend, you’ll gain weight. In addition to the calories it contains, sugar may also expand your waistline by causing you to eat more than you normally would. One paper found that participants who ate a high-glycemic (high-sugar) meal ended up eating 53 percent more calories in the five hours following that meal than subjects who ate a medium-glycemic meal and 81 percent more calories than those who ate a low-glycemic meal.
Sugar can also influence hormones that affect weight. As a 2019 paper published in Medical Hypotheses pointed out, the body deals with the sudden spikes in blood glucose that sugar causes by secreting insulin. Insulin allows glucose to be used by cells but also causes any unneeded glucose to be stored as fat. If you eat large amounts of sugar long enough, your body becomes resistant to insulin’s effects and your pancreas has to secrete more and more insulin, leading to weight gain. In fact, as the paper noted, insulin resistance is a defining characteristic of obesity.
Bloated? You might be eating too much sugar
Do you frequently experience tummy troubles or feel bloated after a sugar binge? Pigging out on sweets may be negatively affecting your gut microbiome. This ecosystem of billions of microorganisms (mostly bacteria) resides in your large intestine and performs a number of important functions, including helping to break down food, producing certain vitamins, and protecting the body against foodborne pathogens. Everyone’s gut microbiome is unique, but for optimal health it’s important that this collection of microorganisms be large and diverse.
According to a 2017 study published in Physiology & Behavior, a high-sugar diet appears to decrease microbiome diversity and upset the balance between the two most commonly found types of gut bacteria. It also promotes inflammation in the gut and disrupts the nerves that allow your brain and digestive tract to communicate with one another.
Additionally, fructose (found in fruit, table sugar, and high-fructose corn syrup) is a FODMAP. FODMAPs are a group of carbohydrates that some people have difficulty digesting. Individuals with a sensitivity to fructose may experience gas, bloating, abdominal pain, diarrhea, or constipation when they consume even small amounts.
Brain fog can come from eating too much sugar
Brain fog, according to Patient, is "a general term for a set of symptoms affecting the cognitive processes. It isn’t a medical condition in itself, but rather occurs as common feature of other conditions." Brain fog can cause problems with memory, information processing, concentration, higher-level thought, and speaking to or understanding others.
Healthline noted that both high and low blood glucose levels can cause brain fog. Eating too much sugar can lead to a spike in blood glucose (hyperglycemia) and, after insulin is released to deal with the sugar, individuals may experience a sudden drop in blood glucose (hypoglycemia). But eating too much sugar may have more dire consequences for your brain than just the occasional mental fuzziness.
In a 2013 paper published in the journal Appetite, researchers explored the link between the "Western diet," which is high in sugar-rich refined carbohydrates, and long-term brain health using animal data. The researchers found that such a diet negatively impacted learning, memory, cognition, and hedonics (the ability to experience pleasure and displeasure). This diet also appeared to be linked to conditions such as attention deficit hyperactivity disorder (ADHD) and neurodegenerative diseases such as Alzheimer’s.
Joint pain can result from eating too much sugar
If you wake up feeling achy, sugar may be to blame. According to Healthline, sugar promotes inflammation in several ways. It leads to excess production of advanced glycation end products (AGEs), inflammatory compounds that form when fat or protein combine with sugar in the bloodstream. Sugar also increases intestinal permeability, raises LDL ("bad") cholesterol, and leads to increases in body fat, all of which have been linked to chronic, low-grade inflammation. In turn, chronic inflammation is believed to underlie or exacerbate a number of health conditions, including heart disease, diabetes, and arthritis.
That’s bad news for the nearly one in three Americans between the ages of 18 and 64 living with arthritis. Among individuals with arthritis, half have persistent joint pain and one in four have severe joint pain, the Centers for Disease Control and Prevention reported.
Inflammation is a double-edged sword. According to Harvard Men’s Health Watch, acute inflammation occurs immediately after an injury and produces warmth, redness, swelling, and pain. This brings white blood cells to the area, where they can begin the healing process. But if the inflammatory response becomes chronic, the body becomes confused and begins attacking healthy tissue.
Your new cavities are probably from eating too much sugar
According to the National Institutes of Health, 92 percent of Americans aged 20 to 64 have had at least one cavity in their permanent teeth, and 26 percent live with untreated cavities. We’ve all heard that "sugar rots your teeth," and unfortunately for those with a sweet tooth, there’s plenty of research backing that up. One paper, for instance, published by Dr. Paula Moynihan in the journal Advances in Nutrition in 2016 noted that the World Health Organization’s recommendation to keep added sugars to less than 10 percent of daily calories (and, ideally, less than 5 percent) was based largely on the connection between sugar and cavities.
But how exactly does sugar damage your teeth? According to Healthline, dental plaque is actually a waste product created by harmful bacteria that live in your mouth and feed off of the sugar you consume. When this plaque builds up, it makes your mouth more acidic, which erodes tooth enamel and creates cavities. The two species of bacteria most likely to cause cavities are Streptococcus mutans and Streptococcus sorbrinus. Soda (which is already acidic) and any sugary treat that stays in your mouth a long time (such as a hard candy) are particularly damaging.
Eating too much sugar can lead to breakouts
Unfortunately, acne doesn’t always go away after adolescence. According to a paper published in 2014 in The Journal of Clinical and Aesthetic Dermatology, 12 to 22 percent of women and 3 percent of men continue to experience acne into their 20s, 30s, and beyond.
The Mayo Clinic highlighted four underlying causes of acne: excess oil production, clogged hair follicles, bacteria, and inflammation. The health care company noted that diet, particularly dairy products and sugary foods, may worsen acne. This connection has been noted in a number of studies, including a paper published in the Journal of the Academy of Nutrition and Dietetics in 2014 (via Healthline). The researchers found that individuals with moderate to severe acne ate more added sugar and total sugar than those with no or mild acne.
One explanation for the link between sugar and acne, proposed in a study published in the journal Molecular Nutrition & Food Research in 2008, is that eating sugar causes a spike in blood sugar, which requires the body to release insulin. But insulin also encourages the release of androgens and other substances that encourage the body to produce more pore-clogging sebum (oil).
Recurring yeast infections can be a sign of eating too much sugar
Yeast infections are an uncomfortable fact of life for many women. According to the Office of Women’s Health, 75 percent of women will have at least one yeast infection in their lives, and nearly 50 percent will have two or more.
Although the gastrointestinal and reproductive systems aren’t directly connected, what you put into the former can have a big impact on what happens in the latter. In an interview with Health, Dr. Jessica Shepherd, OB-GYN, said, "When there’s too much sugar in the body, the immune system becomes suppressed and unable to ward off any bad bacteria; that can lead to an overgrowth of yeast in the vagina."
In the same article, Dr. Lakeisha Richardson explained that excess sugar consumption causes blood glucose levels to rise, and when this sugar-laden blood circulates to the vagina (which has a lot of blood vessels), it becomes food for the yeast that normally reside there. "When you have normal glucose control, the yeast in your vagina doesn’t get enough sugar to grow. But when that excess sugar passes through the area, you create an environment where yeast has more than enough nutrients to overgrow," Richardson explained.
If you’re feeling down, sugar may be to blame
Even though your first instinct may be to reach for a sugary treat when you’re feeling down, that pint of Ben & Jerry’s is likely hurting, rather than helping, your mental health. According to Healthline, consuming too many simple sugars can increase your risk for depression and mood disorders. Sugar promotes inflammation within the body, and inflammation may be an underlying cause of some forms of depression.
In fact, the link between sugar and depression is so compelling that researchers have begun to experiment with the use of diabetes drugs to treat depression in individuals with insulin resistance (a condition in which the body doesn’t respond normally to insulin, leading to elevated blood glucose levels). In one 2016 study published in Psychiatry Research, participants with depression were given pioglitazone, a medication that makes the body more sensitive to the effects of insulin, for 12 weeks. The medication improved their ability to regulate blood sugar, and this in turn led to improvements in their depression symptoms.
According to the Anxiety and Depression Association of America, 16.1 million American adults (6.7 percent of the U.S. population) have depression. While simply cutting out sugar shouldn’t take the place of antidepressant medication or therapy, it may be a helpful step.
Eating too much sugar can lead to high cholesterol
The Centers for Disease Control and Prevention reported that 93 million American adults have a total cholesterol level greater than 200 mg/dL, and approximately 29 million have levels higher than 240 mg/dL. The CDC noted that high cholesterol is a risk factor for heart disease, the leading cause of death in the United States.
While dietary fat is often blamed for raising cholesterol levels, sugar may have an even bigger role to play. A study published in the Journal of the American College of Cardiology in 2007 followed more than 15,000 women for nine to 11 years and concluded that those who ate more sugar-rich refined carbs had higher cholesterol levels and were at greater risk for developing cardiovascular disease.
Another study, published in the Journal of the American Heart Association in 2020, looked specifically at the link between sugar-sweetened beverages such as soda and cholesterol issues. They found that individuals who consumed more than one serving of a sugary beverage per day had lower HDL ("good" cholesterol) and higher triglyceride levels than those who consumed less than one sugary drink per month.
Your sugar habit may lead to high blood pressure
According to the Centers for Disease Control and Prevention, 45 percent of American adults have high blood pressure, defined as a systolic pressure greater than or equal to 130 mmHg or a diastolic blood pressure greater than or equal to 80 mmHg. Systolic pressure is the pressure of blood in the arteries while the heart is contracting and diastolic pressure is the pressure of blood in the arteries in between heartbeats. High blood pressure increases your risk for both heart disease and stroke. While we often blame salt for high blood pressure, sugar may have a similarly, if not more, important role to play.
A 2014 study published in The American Journal of Clinical Nutrition found that children who consumed the most added sugar had higher diastolic blood pressure than those who consumed the least amount of sugar. Interestingly, the researchers found no significant correlation between salt intake and blood pressure. Additionally, a study of older women published in Nutrients in 2019 developed a statistical model that predicted that decreasing daily sugar consumption by 2.3 teaspoons would lead to a drop in systolic pressure of 8.4 mmHg and a drop in diastolic pressure of 3.7 mmHg.
Eating too much sugar can put you at risk for diabetes
Prediabetes is a condition in which an individual’s blood sugar levels are higher than normal, but not high enough to be diagnosed as type 2 diabetes. More than one in three adults — 88 million Americans — have prediabetes, and most don’t even know it. Prediabetes is reversible through diet and lifestyle changes but if left unaddressed, it may become diabetes. Type 2 diabetes can lead to a number of serious complications, including vision loss, kidney failure, and foot amputations.
According to Healthline, eating a diet high in sugar can increase your risk for diabetes both directly and indirectly. Fructose, a type of simple sugar that gives high-fructose corn syrup its name and makes up half of regular table sugar, can damage the liver, which in turn can lead to insulin resistance. This in turn makes it difficult for your body to properly control blood sugar levels. Eating too many sugar-rich foods can also lead to weight gain and more belly fat, both of which are risk factors for diabetes.
A paper published in the Mayo Clinic Proceedings in 2015 concluded that reducing intake of added sugars to less than 5 percent of total calories would improve individuals’ glucose control and lower risk for diabetes.
If you have a nutritional deficiency, it may be because you’re eating too much sugar
Sometimes what’s not in a food is just as important as what is. Added sugars are considered "empty calories." This means they provide calories the body can use for energy but offer nothing else of value for maintaining good health. Added sugars contain none of the vitamins, minerals, or antioxidants found in whole foods. Eating a few empty calories is no big deal as long as the rest of your diet is packed with nutrient-dense foods. The problem is that many Americans are filling up on empty calories and not getting enough micronutrients from foods like fruits and vegetables.
According to Oregon State University, many Americans don’t meet the recommended intake levels for a wide variety of nutrients, including iron, vitamin A, calcium, and potassium. Getting too little of these and other important micronutrients can lead to deficiencies, which have a wide array of negative consequences. Vitamin A deficiency, for example, can cause blindness, and a lack of calcium can lead to brittle bones. Iron deficiency (the most common nutritional deficiency) can lead to anemia.