What Do Artificial Sweeteners Do to Your Body?

By: Alyssa Langer, R.D., L.D.N.

They're sugar-free and zero-calorie, but are artificial sweeteners good for you? Here's what these faux sugars do to your body, brain and gut.

Sugar is everywhere, so it's no surprise that the average American consumes almost 17 teaspoons of added sugars per day (that's more than 1/3 cup, and adds up to 34 pounds of sugar per year). And though there's no denying the wonderfully sweet taste it provides in so many of our favorite baked goods, beverages, condiments and more, sugar contributes extra calories—without healthful nutrients—to our diets.

The American Heart Association recommends that most women cap their added sugar intake at 6 teaspoons per day (9 teaspoons for men). Excessive caloric intake from added sugar (not from natural sources of sugar like whole fruit or dairy products) can lead to weight gain—and thus may indirectly lead to many other health issues—as well as dental cavities. Natural sugars in fruits and dairy are much harder to overeat (most of us can put down the yogurt but will go back for multiple pieces of candy) and also generally come paired with healthful fiber and other nutrients.

When trying to cut back on sugar, many people turn to artificial sweeteners (aka low-calorie or nonnutritive sweeteners) to satisfy their sweet tooth, without the caloric consequences. But it's important to know that these sweeteners can also impact your body. Some of the more common potential issues include headaches, stomach upset, cravings, weight loss and—ironically—weight gain.

Keep Reading: 10 Surprising Food Sources of "Natural" & Artificial Sweeteners

Artificial Sweeteners & Your Body

Headaches

Though some people believe their headaches or migraines are triggered by artificial sweeteners, a 2017 review of studies published in Nutrition Journal found no significant association between noncaloric sweeteners and headaches. However, the American Migraine Foundation does list artificial sweeteners, specifically aspartame, as possible triggers. If you suffer from headaches or migraines and think artificial sweeteners may be to blame, keeping a food diary can help pinpoint the trigger. Talk to your doctor as well.

Read More: 4 Sneaky Health-Food Ingredients to Watch Out For

Digestive Issues

Some people experience stomach pain, diarrhea or gas when they consume artificial sweeteners. The sugar alcohol varieties, in particular—sorbitol, mannitol and xylitol, may have a laxative effect. If you think you might be sensitive, check labels, especially on items like chewing gum and sugar-free candies, which tend to contain these.

Weight Gain

Although many people use artificial sweeteners to help cut calories for weight maintenance or loss, studies have shown they can be counterproductive and actually cause weight gain.

Yes, consuming sugar substitutes as a replacement for regular sugar will decrease your calorie intake. However, if you overcompensate by eating other highly caloric foods (for example, "If I get the diet soda, I can order the French fries"), the benefit becomes neutralized (or could even backfire and cause weight gain). That's why it's important to think about sugar substitutes within the context of your entire diet.

On a biological level, researchers have found that sweeteners may interfere with our metabolisms and the way our bodies physiologically respond to sweetness. When we taste sweet foods, our bodies instinctively react by releasing hormones and activating our metabolisms to prepare for an incoming sugar load. These processes help keep blood glucose under control and regulate appetite. But artificial sweeteners may "trick" the body; when consumed, the body doesn't actually receive any sugar or calories, so it may stop releasing hormones and revving the metabolism. This can be problematic because if caloric foods are consumed later on, the body may not be as well-prepared to metabolize the sugar load, which could potentially lead to higher blood glucose and weight gain.

Researchers are also looking at how noncaloric sweeteners may alter the balance of gut bacteria, which are increasingly being recognized for their role in metabolism and general health. A 2014 study in Nature linked high intake of saccharin with changes in gut bacteria that led to glucose intolerance, a metabolic condition also known as prediabetes.

Read More: A Buyer's Guide to Sugar Substitutes

Cravings

Because many artificial sweeteners are actually much sweeter than sugar, frequent or heavy use may lead to a preference for supersweet foods.

For example, sucralose (Splenda) is 600 times as sweet as sugar; aspartame (NutraSweet, Equal) is 180 times as sweet as sugar; and saccharin (Sweet'N Low, Sweet Twin) is 300 times as sweet as sugar. Regular use of these sugar substitutes can accustom your palate to very sweet foods, potentially leading to cravings or a dependence on sugar, and to increased calorie intake down the line.

Bottom Line

Many people eat artificial sweeteners frequently—from prepared or processed foods, and used in their own baking—and are entirely unaffected. For people with diabetes and other health conditions who are trying to manage blood sugar levels, these sweeteners can be a very helpful option.

But even if any harmful effects are not clear, it's important to remember that eating lots of sugar substitutes is not necessarily "better" than eating sugar. Keep in mind that one sugar packet contains 15 calories, which, in the grand scheme of an average 2,000-calorie per day diet, isn't very much. If you are only reaching for a packet or two per day to sweeten your morning cup of coffee or tea, you might as well stick to the real stuff. Artificial alternatives may be a suitable option (in moderation) if you rely on much more sweetener than just a packet or two (to the point at which the sugar calories could really add up and impact weight).

Try These: 5 Tasty Tricks to Make Clean-Eating Desserts Without Added Sugar

But, on a broader level, be aware of how much added sweetener you're using—sugar or substitutes—and try to gradually lessen it overall by retraining your palate. Choose water over soda, unsweetened tea or coffee over sweetened varieties, and throughout the day, try to eat more natural sources of sugar as opposed to added (think whole fruits versus fruit candies), as these will provide your body with much more nutrition overall.

Watch: Is Diet Soda Bad For You?

Keep Reading:
30-Day Challenge to Slash Your Sugar
Desserts Without White Sugar
No-Sugar-Added 1-Day Meal Plan