The sweet danger of sugar - Harvard Health (2024)

Too much added sugar can be one of the greatest threats to cardiovascular disease. Here's how to curb your sweet habit.

Sugar has a bittersweet reputation when it comes to health. Sugar occurs naturally in all foods that contain carbohydrates, such as fruits and vegetables, grains, and dairy. Consuming whole foods that contain natural sugar is okay. Plant foods also have high amounts of fiber, essential minerals, and antioxidants, and dairy foods contain protein and calcium.

Since your body digests these foods slowly, the sugar in them offers a steady supply of energy to your cells. A high intake of fruits, vegetables, and whole grains also has been shown to reduce the risk of chronic diseases, such asdiabetes, heart disease, and some cancers.

Consuming too much sugar

However, problems occur when you consume too muchadded sugar— that is, sugar that food manufacturers add to products to increase flavor or extend shelf life.

In the American diet, the top sources are soft drinks, fruit drinks, flavored yogurts, cereals, cookies, cakes, candy, and mostprocessed foods. But added sugar is also present in items that you may not think of as sweetened, like soups, bread, cured meats, and ketchup.

The result: we consume way too much added sugar. Adult men take in an average of 24 teaspoons of added sugar per day, according to the National Cancer Institute. That's equal to 384 calories.

"Excess sugar's impact on obesity and diabetes is well documented, but one area that may surprise many men is how their taste for sugar can have a serious impact on their heart health," says Dr. Frank Hu, professor of nutrition at the Harvard T.H. Chan School of Public Health.

Impact on your heart

In a study published in 2014 inJAMA Internal Medicine, Dr. Hu and his colleagues found an association between a high-sugar diet and a greater risk of dying from heart disease. Over the course of the 15-year study, people who got 17% to 21% of their calories from added sugar had a 38% higher risk of dying from cardiovascular disease compared with those who consumed 8% of their calories as added sugar.

"Basically, the higher the intake of added sugar, the higher the risk for heart disease," says Dr. Hu.

How sugar actually affects heart health is not completely understood, but it appears to have several indirect connections. For instance, high amounts of sugar overload the liver. "Your liver metabolizes sugar the same way as alcohol, and converts dietary carbohydrates to fat," says Dr. Hu. Over time, this can lead to a greater accumulation of fat, which may turn into fatty liver disease, a contributor to diabetes, which raises your risk for heart disease.

Consuming too much added sugar can raise blood pressure and increase chronicinflammation, both of which are pathological pathways to heart disease. Excess consumption of sugar, especially in sugary beverages, also contributes to weight gain by tricking your body into turning off its appetite-control system because liquid calories are not as satisfying as calories from solid foods. This is why it is easier for people to add more calories to their regular diet when consuming sugary beverages.

"The effects of added sugar intake — higher blood pressure, inflammation, weight gain, diabetes, andfatty liver disease— are all linked to an increased risk for heart attack and stroke," says Dr. Hu.

How much is okay?

If 24 teaspoons of added sugar per day is too much, then what is the right amount? It's hard to say, since sugar is not a required nutrient in your diet. The Institute of Medicine, which sets Recommended Dietary Allowances, or RDAs, has not issued a formal number for sugar.

However, the American Heart Association suggests that women consume no more than 100 calories (about 6 teaspoons or 24 grams) and men no more than 150 calories (about 9 teaspoons or 36 grams) of added sugar per day. That is close to the amount in a 12-ounce can of soda.

Subtracting added sugar

Reading food labels is one of the best ways to monitor your intake of added sugar. Look for the following names for added sugar and try to either avoid, or cut back on the amount or frequency of the foods where they are found:

• brown sugar
• corn sweetener
• corn syrup
• fruit juice concentrates
• high-fructose corn syrup
• honey
• invert sugar
• malt sugar
• molasses
• syrup sugar molecules ending in "ose" (dextrose, fructose, glucose, lactose, maltose, sucrose).

Total sugar, which includes added sugar, is often listed in grams. Note the number of grams of sugar per serving as well as the total number of servings. "It might only say 5 grams of sugar per serving, but if the normal amount is three or four servings, you can easily consume 20 grams of sugar and thus a lot of added sugar," says Dr. Hu.

Also, keep track of sugar you add to your food or beverages. About half of added sugar comes from beverages, including coffee and tea. A study in the May 2017Public Healthfound that about two-thirds of coffee drinkers and one-third of tea drinkers put sugar or sugary flavorings in their drinks. The researchers also noted that more than 60% of the calories in their beverages came from added sugar.

Yet, Dr. Hu warns against being overzealous in your attempts to cut back on added sugar, as this can backfire. "You may find yourself reaching for other foods to satisfy your sweet cravings, like refined starches, such as white bread and white rice, which can increase glucose levels, and comfort foods high in saturated fat and sodium, which also cause problems with heart health," he says.

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