Sugar: The Science Behind Your Sweet Tooth

It’s 2 o’clock in the afternoon and you’re feeling a little sleepy after lunch. Instinctively, you reach for that soda or piece of candy. Something tells you that maybe you shouldn’t, but you do anyway. Feeling guilty? You’re not alone!

Like millions of Americans, you probably count on a quick sugar high to get your through the day, but too much sugar can take a toll on your health and fitness goals. In this article, we explain the difference between good and bad sugars, and why it’s important to keep an eye on your sugar intake.

Why you crave sugar

Sugar is an addictive substance that triggers dopamine release in the brain, leading to feelings of pleasure. In one study, when rats were offered a sugar solution and their normal food after a fasting period, they chose to drink the sugar solution as soon as it was offered 1. In this experiment, the animals showed behaviors similar to the effects of drug abuse—going through binging, withdrawal, and craving on this feeding schedule.

Unfortunately, sugar’s addictive qualities and the prevalence of sugar in American diets is taking a toll on our health and well-being. While sugar naturally occurs in many foods, such as fruits, it’s added sugars that are of concern. Added sugars include all sugars used as ingredients in processed and prepared foods such as breads, cakes, soft drinks, jams, chocolates, ice cream, and sugars eaten separately or added to foods. (See more examples of added sugars below under “Processed sugars.”)

Increased consumption of sugar has been linked to weight gain and a decreased intake in other essential nutrients 2. And it’s no surprise that sugar intake trends high in Americans, often exceeding official recommendations:

  • In 2005-2010, the average intake from added sugars averaged about 12.7 percent of an American man’s caloric intake, and 13.2 percent of a woman’s, according to the Centers for Disease Control and Prevention 3.
  • U.S. Department of Health dietary recommendations recommends limiting calorie intake from sugars and solid fats to between 5 and 15 percent a day 4.

So, just how much sugar should you consume?

Some helpful guidelines on sugar consumption were recently issue by the Food and Drug Administration (FDA). Americans should limit added sugar to no more than 10 percent of daily calories 5. For an adult, that means consuming no more than 12.5 teaspoons (or 50 grams) of added sugar a day, the equivalent of the amount of sugar in a can of Coke. Sounds strict, right? We think so too, but this could be the kick in the butt we need to start weaning ourselves off our reliance on sugar and start eating more healthfully.

So many kinds of sweetness

Sure, sugar may have a bad rep, but there are differences in the type of sugar out there. Chemically, sugar is made up of glucose and fructose. There’s not one type of sugar that is better or worse for you. Too much of any type of sugar will ultimately cause you to gain weight. The difference is that fructose and glucose affect your body differently and are metabolized differently.

  • Fructose, the main sweetener in soda and juices, can only be metabolized by the liver and is not necessary for survival. The bottom line: When we consume more fructose than our liver can process, fructose is turned into fat, contributing to weight gain.
  • Glucose, on the other hand, can be metabolized by nearly every cell and requires a release of insulin into the bloodstream in order to be completely metabolized. Studies examining the effects of glucose vs. fructose found that both kinds of sugars caused weight gain when consumed in excess, although fructose was more commonly linked to a higher risk for heart attack and stroke 6.
  • Sucrose (sometimes called saccharose) is the combination of both fructose and glucose.

Most fruits have between 40-55 percent fructose, and table sugar (sucrose) has about 50 percent fructose. But just because fruit and table sugar have a similar composition doesn’t mean that they should be interchangeable 7.
Fruits contain important vitamins, antioxidants, and water and tend to have less sugar by volume, while snacks like cookies and candy typically contain more contain more sugar without the nutrition value. For example, half a cup of strawberries contains 3.7 grams a sugar 8, while half a cup of ice cream contains 14 grams 9.

Processed sugars

Although all sugars are technically “natural”, most of the ones that we consume today are refined. The refining process removes most essential nutrients which results in foods bringing you nothing but calories. Even sugars from agave cacti, sugar cane, maple trees, coconut palms, corn, or sugar beets are processed and have little nutritional value and actually make you feel hungrier faster. The reason is because refined sugar is digested more quickly than sugar found in fruit. The fiber in fruit also slows down the digestion of sugar and makes you feel more full. 10

Examples of processed or added sugars include:

  • White or table sugar (sucrose). We all know those little white sugar packets that you get with your coffee at restaurants across the nation.
  • High fructose corn syrup, a corn-based sweetener, is one of the most common sweeteners in processed American foods today (it’s a cheaper replacement to table sugar), contributing to one of the most significant changes to our food supply in the century.
  • Agave syrup. Often advertised as healthier or natural, as it has a lower glycemic index (a measure of how quickly a food is broken down to glucose in the body), agave syrup is actually very high in fructose. That means it goes almost immediately to the liver, and any fructose that isn’t needed will turn into fat.
  • Brown rice (malt) syrup is derived by cooking down rice starch, and is readily available in stores as maltose or maltose syrup. It has a higher glycemic index than table sugar.
  • Other sugars. You may be surprised that maple syrup and pancake syrup are considered added sugars because they are actually processed. Other sugars that may be lurking in processed foods include fructose sweetener, liquid fructose, honey, molasses, anhydrous dextrose, crystal dextrose, and dextrin.

Naturally-occurring sugars

Whenever possible, choose foods that contain naturally occurring sugars in their native form, such as whole fruits and vegetables. However, beware that even though some foods contain sugar naturally, their high sugar content can lead to weight can if not consumed in moderation. Examples of fruits and vegetables with higher sugar levels include dried fruits, lychees, figs, mangoes, cherries, and grapes. Lower sugar ones include avocados, raspberries, blackberries, and strawberries 11.

Sugar levels in common foods

Food Serving Size Sugars
Apple 1 medium 19 grams
Avocado ⅕ medium 0 grams
Grapes ¾ cup 20 grams
Pear 1 medium 16 grams
Orange 1 medium 12 grams
Orange juice 1 cup 21 grams
Apricot (dried) ¼ cup 17 grams
Apricot (fresh) 1 medium 3 grams
Cola 16 fl. oz, without ice 31 grams
Milkshake 12 fl oz 34 grams
Milk chocolate 1 bar  (1.55 oz) 23 grams

Source: FDA Nutritional Information on Raw Fruits, USDA National Nutrient Database

Artificial sweeteners

Finally, there’s artificial sweeteners, such as aspartame, saccharin, and sucralose, which are chemically manufactured molecules that do not exist in nature 12. Found in sodas, candy, canned and packaged foods, people often turn to sugar substitutes when trying to reduce sugar in one’s diet. Even though these synthetic sugar substitutes don’t add calories to your diet and have been “generally recognized as safe” by the FDA, they have been scrutinized for causing health problems, including cancer.

Artificial sweeteners are also not necessarily the better choice as consuming them is often linked to metabolic disorders. Your body thinks you’re about to ingest real sugar and starts the processes for metabolizing sugar, such as releasing insulin. As a result, you’ll experience a decrease in blood sugar, which causes what we’re all too familiar with: the munchies. In this sense, artificial sweeteners don’t do much to appease your sugar cravings. In fact, it makes it easier to just go right back into indulging in sweets. Your best bet is to cut back on diet sodas and foods containing artificial sweeteners to avoid interrupting your body’s metabolism.

3 reasons sugar is bad for you

  • Weight gain and obesity are the most obvious effects of excess sugar consumption. Numerous studies have shown that increased consumption of sugary beverages contributes to weight gain, heart disease and tooth decay 13. The more you consume, the greater your chances of health problems.
  • Heart disease. Increased sugar consumption was also shown to correlate with a significant increase in 14. Over a 15-year study, those who consumed 25 percent or more of their calories from sugar were twice as likely to die from cardiovascular disease compared with those who consumed less than 10 percent of calories from sugar.
  • Tooth decay is another downfall of eating too much sugar. Sugar consumption causes excessive acid to form, which then enhances the damage to your enamel caused by the bacteria in your mouth. That’s when cavities occur.

Moderation is key

If you want to lose weight, and just live a healthier life, simply cutting out added sugars can make a huge difference. But we know, it’s not easy. What it all comes down to is moderation. “If eaten in moderation, the source of sugar doesn’t really matter, because in the end sugar is sugar,” says Coach Jennifer, 8fit nutritionist. “Alternative sweeteners like honey or dried fruits are not necessarily much more healthy than white/brown sugar.”

Next week: 8fit Low Sugar Challenge

Introducing 8fit’s nutrition challenge. Stay tuned for tips on how to reduce added sugars in your diet!

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