Can Our Bodies Even Tell the Difference Between Naturally Occurring and Added Sugars?

If you regularly read nutrition labels—or, ya know, half-heartedly skim them on occasion just for the hell of it—you may have noticed a couple new lines appearing on more and more products. Food manufacturers are now listing “Total Sugars” and “Added Sugars” in the Nutrition Facts (under “Total Carbohydrate”), thanks to a new Food and Drug Administration (FDA) requirement. That kind of implies added sugars are officially something you need to be wary of.

But what does “added sugar” even mean? Is it somehow inherently worse for us than naturally occurring sugar? We have a lot of questions, so we went digging for answers.

Here’s what we mean when we say “naturally occurring” versus “added” sugars.

To put it simply, added sugar is any sugar that was added to the food at some point, while naturally occurring sugar is just inherently already in the food.

Naturally occurring sugars are the kinds found in all fruits (fresh, frozen, dried, canned in 100 percent fruit juice), many dairy products (like milk and yogurt), some vegetables (like sweet potatoes and corn), and 100 percent fruit and vegetable juices. Basically, they are an inherent part of the foods they’re found in—nobody put them there.

Added sugars, on the other hand, are the kinds created or put in during the manufacturing process. They sometimes appear solo in their pure form as the ingredients you use to whip up a batch of cookies (granulated sugar, molasses, brown sugar) or liven up your oatmeal in the morning (honey, maple syrup, coconut sugar). Added sugars also commonly appear in baked goods or packaged foods, under those names and in less familiar forms, health and wellness coach Kim Larson, R.D.N., tells SELF. That includes pretty much anything containing the word “syrup” (like corn syrup, malt syrup, and high-fructose corn syrup) or ending in “-ose,” Larson explains: dextrose, fructose, glucose, lactose, maltose, sucrose, and trehalose.

You can find added sugars in the obvious (pastries, ice cream, cereal, cookies, candy, soda, muffins, cakes) and the stuff we don’t think of as classic sweets (bread, salad dressing, crackers, pasta sauce), typically in smaller amounts.

Setting aside fresh fruit and vegetables and some plain dairy products, most products containing sugar actually contain some naturally occurring and some added. “Very rarely do you come across something that doesn’t have anything added to it to make it just a tiny more sweet or balance out the flavors,” Colleen Tewksbury, Ph.D., M.P.H., R.D., a senior research investigator and bariatric program manager at Penn Medicine and president-elect of the Pennsylvania Academy of Nutrition and Dietetics, tells SELF.

For example, granola might contain some naturally occurring sugar from raisins or dates, along with some added sugar to sweeten up the oats, like honey. Tomato sauce contains naturally occurring sugars from tomatoes, along with, often, additional white sugar to counteract the natural acidity of the tomatoes. And an average strawberry yogurt will contain naturally occurring milk sugars in the plain yogurt itself and fruit sugars in the strawberries, in addition to some added sugars (like corn syrup). That’s why this labeling change will be helpful, Larson says, so people can more quickly discern how much added or naturally occurring sugar is in something.

Just to be clear, we’re not even getting into the huge variety of non-sugar sweeteners that can also be found in packaged foods. Sugar substitutes made in a lab (like saccharin and sucralose) or derived from nature (like stevia or monk fruit), which the FDA classifies as high-intensity sweeteners, are a totally different ballgame in terms of their chemical structure and effects on our bodies. Like added sugars, they are added to foods and beverages to give them a sweet taste—but without altering the sugar or overall nutritional content. They are not composed of sugar molecules and contain zero or very few calories. We’re also not talking about sugar alcohols (like sorbitol or xylitol) for the same reasons. Yes, these things taste sweet like sugar, but they don’t factor into our discussion here because they’re not actually sugar.

So, do different sugars impact our body differently?

Now that we’re clear on WTF naturally occurring and added sugars really are, let’s talk about whether your body even cares one way or the other.

“From a nutrition science standpoint, we really view them as basically the same,” Tewksbury says. “Our bodies can’t tell the difference whether it’s found in nature or added to a recipe, because they’re not any different in terms of their chemical structure.”

On a molecular level, there are two main kinds of sugars, the FDA explains, and most foods contain some of both. The first is monosaccharides, or single sugar molecules, which include fructose, galactose, and glucose. These go pretty much directly into the bloodstream after you eat them. The second is disaccharides, which are just two of these single sugar molecules linked together: sucrose, or table sugar (glucose + fructose); lactose, or milk sugar (glucose + galactose); and maltose, or malt sugar (glucose + glucose). These get quickly broken down by the liver into single glucose molecules before entering the bloodstream—so they raise your blood sugar just slightly more slowly, Tewksbury says.

All of the naturally occurring and added sugars we eat are simply some combination of these molecules. “What we call naturally occurring sugars aren’t more natural, per se, than added sugars,” Tewksbury says. “The glucose you find naturally occurring in a grape is going to be the same as the glucose in table sugar,” Tewksbury says. So while we distinguish between naturally occurring and added sugars on food labels, our bodies don’t distinguish between a molecule of fructose, glucose, sucrose, or whatever other sugar molecule you consume. We digest them all in generally the same way.

But wait! What about natural added sugars, you ask? Like honey and agave syrup. While “natural” might sound inherently good or better, it doesn’t really mean anything in this case. Sure, some of the ingredients we classify as “added sugars” are less refined than others and pretty close to the original form in which they’re found in nature, like maple syrup. Added sugars can also be extracted from foods with naturally occurring sugars and concentrated, like in the case of peach nectar or pear nectar. But the sugar molecules in a tablespoon of honey are not going to be superior to the sugar molecules found in a tablespoon of white sugar. “Chemically, [natural sugars] affect you exactly the same as table sugar,” Tewksbury says. Plus, you could argue that virtually all sugars are “natural” in some sense, given that they’re derived from something once found in nature. Even powdered sugar, for example, has just been refined from the sugarcane plant. So the term “natural sugar” sounds nice but doesn’t mean much.

Should we care, then, about added sugar in packaged foods?

If our bodies can’t even distinguish between a molecule of sugar from a banana or a brownie, then why even differentiate between the two on nutrition labels? Well, that’s a good question. It would seem that since, to our bodies, sugar is sugar, it wouldn’t really matter. If you’re trying to limit your sugar intake for whatever reason, looking at the total grams of sugar, no matter the source, is a sufficient way to do so.

But that doesn’t mean calling out added sugars is necessarily useless. Products with a ton of added sugar in them are foods that are processed, which means that there’s a decent chance other important nutrients could have been stripped out in the process of making the food sweeter and more desirable for consumers.

Foods consisting of only naturally occurring sugars, on the other hand, are typically inherently full of other good stuff, like fiber (in fruit), protein (in dairy products), and vitamins and minerals (in both fruit and dairy products), Larson says.

And those costarring nutrients can affect how your body reacts to the sugar in that food. Consider a piece of fruit-flavored candy compared to a pear, each with 10 grams of sugar. The fiber present in the pear (and missing from the candy) can have several positive health effects, like regulating digestion, increasing feelings of satiety, and slowing the breakdown and absorption of sugar into your bloodstream. So even though you’re technically consuming the same amount of sugar from both foods, and those sugars are equivalent in and of themselves, you’ll feel a little more satisfied and your blood sugar won’t spike quite as quickly when you eat the pear, Tewksbury explains. More gradual fluctuations in your blood sugar provide a steadier supply of energy, and are especially helpful for anyone wanting to keep blood sugar levels stable, such as those with prediabetes or type 2 diabetes.