The Truth About Sugar
How much sweet stuff are you really consuming—and what's it doing to your body?
Imagine measuring out nearly 20 teaspoons of pure granulated sugar and eating it, every 24 hours. Over the course of a month, you’d plow through an entire 5-pound bag—and then some. The scary thing is you don’t really have to imagine this scenario, because you’re probably already living it. The average American adult devours almost 20 teaspoons of added sugar, defined as sweeteners added during food processing or preparation, every single day. And the average teenager downs even more. Worse, these 20 teaspoons don’t even include the naturally occurring sugar in fruit and dairy products.
“Some sugar intake is fine,” says Richard Johnson, MD, an internist and kidney specialist at the University of Colorado and author of The Sugar Fix. “The problem is that everyone is getting too much of it.” Sugar is everywhere—it’s in bread, ketchup, flavored yogurt and seasoned nuts. Ultimately, we take in about two to three times more added sugar than the American Heart Association recommends, and many experts believe our love affair with the sweet stuff is fueling the country’s rising incidence of type 2 diabetes, obesity and heart disease—epidemics that are harming not just adults but children too. A 2014 study conducted by Harvard researchers and involving more than 11,000 U.S. adults reported that those who consumed the most added sugar are nearly three times as likely to die of heart disease as those who consumed the least. Another 2014 study found that the more added sugars children eat, the higher their blood pressure and blood triglyceride levels, which are both risk factors for heart problems. This doesn’t mean we need to dump all sweets in the trash, but we should be more careful about which ones we let into our homes—and our bodies.
While some of us crave a sugary cinnamon roll at breakfast or just have to order that molten chocolate lava cake for dessert, added sugar actually has almost no nutritional value and your body doesn’t need it. (Our cells do require small amounts of sugar to function, but the liver can convert protein into sugar, so we don’t have to eat the sweet stuff.) In fact, the U.S. government has no suggested minimum intake for this simple carb. That probably comes as no surprise—everybody has heard of “empty calories”—but even though we know we shouldn’t be having so much, most of us can’t help it.
Part of the problem is that it makes us feel so good. “When you ingest sugar, it gives your body a sense of euphoria—it takes you to a happy place,” explains Brooke Alpert, MS, RD, a nutritionist and co-author of The Sugar Detox. Scientists have actually verified this in the lab: When animals are fed sugar, the reward centers in their brains become active, much as they do after using cocaine and other drugs. Regular consumption of sugar may also dampen the impact of stress, according to a small study in women that is supported by research in rodents as well. “Sugar makes us want to have more sugar, and that sets up a cascade of events that can lead to excess intake and weight gain over time,” explains Icahn School of Medicine at Mount Sinai neuroscientist and addiction researcher Nicole Avena, PhD, co-author of Why Diets Fail.
Drinking sugar is especially problematic. Whereas eating 300 calories’ worth of apple slices will leave you or your child feeling at least somewhat sated—partly because the fiber the fruit contains helps to regulate appetite—drinking 300 calories of apple juice doesn’t have the same effect. Not to mention that some apple juices have added sugars. What’s more, research suggests the juice might even make you hungrier. “Liquid calories do not register very well in our brains,” says Frank Hu, MD, PhD, a professor of nutrition and epidemiology at the Harvard T.H. Chan School of Public Health. “Your stomach and gut don’t produce hormones that make you feel full, which can give you a false signal that you’re still hungryand need more food.”
There may be another reason why sugar makes us gain weight—it has to do with how we process it biochemically. Carbohydrates (everything from candy to pasta) contain molecules of a sugar called glucose. After we consume carbs, this glucose enters our bloodstream and our pancreas releases the hormone insulin to remove it to different cells throughout our body that need energy. Some research, however, suggests insulin may turn too much of that glucose into fat and store it for future use—rather than letting our body use it more immediately for energy. To compensate for this dearth of available fuel, our cells then send signals to our brain to tell us to eat more. In this sense, we may not just get fat because we overeat; we may also overeat because we get fat. And sugar may be the source of both these problems. Keep in mind, once again, that sugar isn’t always sweet—starchy carbohydrates such as bread, rice and potatoes are mainly composed of sugars (glucose) and have these same effects on the body.
Sugar may not just be bad for us because it causes weight gain. In his 2013 book Grain Brain, Florida-based neuroscientist David Perlmutter, MD, argues that too much sugar may also increase the risk for neurological conditions. “More than any other organ in the body, the brain is super responsive to nutritional changes—even more than the heart,” he says. “And there is hell to pay when blood sugar rises.” Perlmutter notes that frequent blood sugar spikes turn on the process of inflammation, which has now been linked to Alzheimer’s, Parkinson’s and even multiple sclerosis. Doctors have long known that people with type 2 diabetes have twice the risk of Alzheimer’s and are more likely than the general population to suffer from other memory-related problems. Perpetually high blood sugar also increases the risk for brain shrinkage.
Chronic inflammation—overactivity of the body’s disease-fighting immune system—may be at the root of these problems. As Perlmutter explains, sugars in the bloodstream can attach themselves to proteins and fats, causing them to change shape in potentially harmful ways while also increasing the body’s production of pro-inflammatory molecules known as free radicals. Sugars also cause the immune system to release other inflammatory immune molecules known as cytokines. A 2014 study reported that women who had more than one soda a day were 63% more likely to develop rheumatoid arthritis, a condition characterized by inflammation in the joints and organs, compared to women who consumed less than one serving a month. Other research points to links between sugar consumption and the risk for endometrial and colorectal cancers.
At this point you might be wondering whether that blueberry muffin you inhaled a few hours ago should be your last. Relax: Most experts agree that you and your family don’t have to completely eliminate sugar to stay healthy. For one thing, the research linking sugar to various ailments doesn’t prove that sugar is the driving factor. People who consume a lot of sugar may do other things that are bad for them too, such as not exercise, drink too much or smoke.
What most health professionals agree on is that we’re eating far too much of the sweet stuff. According to the American Heart Association, women should only be consuming about 6 teaspoons of added sugar a day, the equivalent of your average candy bar or 8 ounces of soda. Men should limit their intake to 9 teaspoons, and children should have no more than 3 to 4 teaspoons—the amount of sugar that can be found in just one granola bar.
Alpert says one of the best ways to reduce sugar intake is to quit all carbs for a few days—no bread, chips, potatoes, sweets or fruit. This can be a challenge, but it works, because “when you start adding sugar back into your diet, you crave less,” she explains. “All of a sudden, an apple tastes really sweet.”
Also, skip the sugar-sweetened beverages, which include sodas, flavored coffees and teas, and sports, energy and vitamin drinks. Research suggests that drinking just one additional soda or sugar-sweetened carbonated beverage a day can cause you to gain up to 15 pounds a year. And since sugary drinks don’t actually fill you up, cutting them out shouldn’t leave you any hungrier. Don’t fall for the “made with real sugar” trick, either. There is no evidence that drinks sweetened with sugar are any healthier than those sweetened with high-fructose corn syrup.
“Processed food is another major culprit to avoid,” says Robert Lustig, MD, a pediatric endocrinologist at the University of California, San Francisco and the author of Fat Chance. “Processed means high sugar, low fiber. Real food is low sugar, high fiber.” Cereals, for instance, are often extremely sugar-laden. Even seemingly healthy options, such as granola, can have more sugar per serving than a doughnut. While it can be difficult to give up processed foods entirely, you can make smart choices: A 2013 study found that carbohydrate-based foods with a ratio of at least one to 10 of fiber to total carbohydrate typically contain less sugar and more fiber than other options.
Don’t be fooled, though—cutting back on sugar isn’t going to be easy. “It really helps to have friends and family be aware of your dietary changes so they can encourage you, and so they’re aware that you might be ‘hangry’ during the first week or so,” Avena says. And keep healthy snacks in your handbag for when hunger strikes, because it will. “One ounce, about a handful, of almonds is a good choice,” Avena suggests. It won’t ever be a breeze, but you may find that limiting sugar gets easier the longer you stick with it. As your body overcomes cravings, you’ll discover how sweet it is to break sugar’s hold on you.