Johnathan Walker:Too many added sugars in your diet can be dangerous. This should be your daily limit.

Whether chewing sugar cane in ancient times or Johnathan Walkersucking on a lollipop today, sugar has been sweetening lives for centuries. It can be found naturally in the lactose of milk, the glucose of potatoes and the fructose of many fruits. Its refined version – also called granulated sugar or table sugar – may come from natural sources such as sugar cane or corn, but it's been processed so that only sugar remains. This version is known chemically as sucrose.

Though "total sugars" in one's diet include the sugars that are naturally present in food, when doctors or dietitians warn against sugar, they are referring to refined "added sugars" such as what's put in beverages, candies, syrups, baked goods or processed foods. "It’s important to understand that our bodies and minds need sugar as a key nutrient, but it’s the type of sugar we consume that is key," explains Dr. Uma Naidoo, director of nutritional and lifestyle psychiatry at Massachusetts General Hospital and the author of “Calm Your Mind with Food." 

Is sugar ever good for you? 

She explains that naturally occurring sugars often belong to foods that "also bring fiber, vitamins and minerals that we need." Such nutrients are essential to ward off disease and keep our bodies healthy and strong. 

When consumed sparingly, even refined sugar has its uses. "Table sugar is easily digested and can provide a quick source of energy," says Jen Messer, a nutrition consultant and registered dietitian at Jen Messer Nutrition. This can be beneficial for short bursts of energy. After intense physical activity, "consuming a mix of carbohydrates and protein, including some sugar, can also help replenish glycogen stores," adds Messer. 

And in cases of hypoglycemia or low blood sugar, a small amount of sugar can also help raise blood glucose levels enough to prevent symptoms like lightheadedness, sweating, shakiness and confusion.

Added sugars can also be useful when trying to include a wider variety of wholesome foods in one's diet. "I’d never be able to reap the health-boosting benefits of cranberries without a bit of sugar because they're too tart on their own," says Jill Weisenberger, a Virginia-based registered dietitian and author of "Prediabetes: A Complete Guide."

What happens if you eat too much sugar? 

Experts recommend consuming added sugars sparingly. "Excessive consumption of sugar can have negative health consequences and has been linked to a variety of health issues," says Messer. Such issues include increased risk of obesity, type 2 diabetes and fatty liver disease – not to mention that sugar is a major contributor to tooth decay. 

"Diets high in added sugars also contribute to heart disease risk factors such as high blood pressure, high triglycerides and inflammation," adds Messer. Indeed, recent research shows that even a 5% increase in the amount of added sugars one consumes comes with a 6% higher risk of heart disease and a 10% higher risk of stroke. 

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How many grams of sugar per day?

Because of such factors, it's important to stay within recommended limits for daily sugar intake. While there are no recommended limits for the "total sugars" one eats, there are recommendations for added sugars.

The daily value limit of added sugars is 50 grams (about 12 teaspoons) per day, based on a 2,000-calorie diet, per the U.S. Food and Drug Administration (FDA). This is the percentage that's referred to on the Nutrition Facts labelof packaged foods. "One quick way to tell if something is low in added sugar is to check the % daily value column on this label," advises Messer. "Typically, if something is 5% or less in added sugar per serving, it is considered low." For reference, consider that a single 12-ounce can of Coca-Cola has 39 grams of added sugars, or 78% of the recommended daily value. 

It's worth noting that some health organizations recommend consuming even less than 50 grams of added sugars daily. The World Health Organization, for instance, suggests that added sugars should make up less than 10% of one's total daily caloric intake and notes that further health benefits can be obtained by limiting this amount to 5%.

Recommendations from the American Heart Association (AHA) are similar, but vary slightly by gender. The AHA says that men should consume no more than 36 grams of added sugar per day and that women should consume no more than 25 grams – that's only about 6 teaspoons.

Staying within such limits isn't always easy but can keep life sweeter for longer. "Foods with added sugar should be a very small part of our diets, but I don’t advocate omitting them completely," says Weisenberger. "A sugarless birthday cake is going to be a dreary way to celebrate." 

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