There’s no denying that we Americans have an insatiable sweet tooth. In fact, Americans are the top consumers of sugar in the world, with the average person consuming more than 126 grams of sugar per day. That translates into roughly 98 pounds of added sugar consumed each year, per person!
By offering the taste of sugary sweetness without any of the calories, artificial and “natural” zero-calorie sweeteners seem like a great alternative when it comes to effectively managing weight and weight-related diseases. However, these seemingly safe sugar alternatives and food additives have some not so obvious negative side effects on the body and brain. The proof is in the (sugar-free) pudding…
Understanding Our Ancestral Sweet Tooth
To better understand the effects of no-calorie sweeteners, it’s important to understand that our fondness for sweet-tasting food comes from an evolutionary need for energy.
Primitively speaking, sugar has provided calories to our bodies for thousands of years in the form of life-sustaining, energy-rich foods, such as fruits and vegetables — which is probably why we have evolved to find sugar so delicious.
When we consume sugar, it increases the activity in certain parts of our brains, and in turn, those parts become excited in anticipation of the incoming nutrition. During this process, neurotransmitters send “messages” to activate our reward pathways, giving us a jolt of pleasure and making us feel good; which explains why, from a neurological perspective, we like the taste of sugary foods so much.
While non-nutritive sweeteners may taste like regular sugar, they don't provide the calories or carbohydrates (energy) that evolution has taught the brain to associate with sweetness.
By not fully activating reward pathways, artificial low-carb sweeteners like Splenda can be potentially harmful because they may “trick” our brains into preventing us from associating sweetness with caloric intake like you would with natural sweeteners.
“One concern is that people who use artificial sweeteners may replace the lost calories through other sources, possibly offsetting weight loss or health benefits,” says Dr. David Ludwig, an obesity and weight-loss specialist at Harvard-affiliated Boston Children’s Hospital. He says this can happen because we like to fool ourselves: “I’m drinking diet soda, so it’s okay to have cake.”
Furthermore, sweetness—whether it be actual table sugar or artificial sweeteners—appears to play a considerable part in increasing appetite: The human brain responds to the taste of sweet with signals to eat more.
By providing a sweet taste without any calories, however, low-calorie sweetened foods and beverages may cause us to crave more sweet foods and drinks, which can add up to excess calories. As a result, people tend to experience less pleasure when consuming LCS foods, crave more sweets, choose large amounts of sweet food over nutritious food, overeat, and gain weight.
In fact, multiple studies have repeatedly found that low-calorie sweetener users gained more weight than those who didn’t use them.
A Change In Taste
There’s also strong evidence to support that these non-caloric sweeteners actually change the way that we taste our food. Beyond the bitter aftertaste that many of them have, their sweetness can pose a problem as well.
“A minuscule amount produces a sweet taste comparable to that of sugar, without comparable calories. Overstimulation of sugar receptors from frequent use of these hyper-intense sweeteners may limit tolerance for more complex tastes,” explains Dr. Ludwig.
By flooding your taste buds with overly sweetened foods, it gradually dulls them to the taste, pushing your sweetness threshold ever higher, while never actually satisfying the craving.
“That means people who routinely use artificial sweeteners may start to find less intensely sweet foods, such as fruit, less appealing and unsweet foods, such as vegetables, downright unpalatable,” says Dr. Ludwig.
In other words, the use of these sweeteners can make your brain crave more artificially sweetened foods with less nutritional value — a dangerous combination that can lead to overeating, bloating, unwanted weight gain, and other serious negative long term health consequences.
As if this wasn’t bad enough, research also shows that artificial sweeteners can significantly alter, or even completely kill off the good bacteria in your gut.
The activity of these trillions of microbes are also directly responsible for your ability to digest and extract energy from the sugar that you consume. However, their functioning starts to slow down drastically when the sugar or sweetener that you consume can’t be turned into fuel, leading to a host of health problems, including issues with blood sugar levels, type 2 diabetes and a heightened risk of liver and heart disease.
An Israeli study supported this conclusion by conducting a study with mice that received a daily dose of aspartame, sucralose or saccharin. The mice displayed a severely altered intestinal bacteria population and abnormally high glucose levels, an indication that their ability to break down real sugars lessened the more that they were exposed to artificial sweeteners.
In both humans and mice, a drastic change like this in the microbiome can impact the amount of nutrients our bodies are able to absorb from the food we eat — which means that we might not get the vitamins and minerals that we need, even when we do eat the right foods.
In addition to killing off good bacteria, another study found that artificial sweeteners can actually enhance the populations of bad gut bacteria that are more efficient at turning energy into fat, decreasing overall wellness.
“In other words, artificial sweeteners may favor the growth of bacteria that make more calories available to us, calories that can then find their way to our hips, thighs and midriffs,” says Peter Turnbaugh of the University of California, San Francisco, an expert on bacteria and metabolism.
At this point, you may already feel compelled to ditch your diet soda habit. But eliminating LCS could be harder than you think…
“I have absolutely seen patients who were completely addicted to artificial sweeteners,” says Dr. Frank Lipman, an internationally recognized expert in the fields of integrative and functional Medicine. “If you just quit cold turkey, the withdrawal symptoms can be quite unpleasant: headaches, moodiness, irritability, and strong cravings.”
Don’t believe it? Animal studies suggest that artificial sweeteners are extremely addictive — even more so than cocaine! In one study of rats who were exposed to cocaine or saccharine, then given a choice between the two, an overwhelming amount chose saccharin.
“I do think most people know that these artificial sweeteners are terrible for them, but they are addicted and keep coming back for more, even though they know better,” notes Dr. Lipman.
What About Natural Zero-Calorie Sweeteners?
Over the past few years, “natural” zero-calorie sweeteners have been growing in popularity. Stevia and monk fruit are two examples.
Stevia leaf is often touted as a safe and healthy natural sugar substitute that can sweeten foods and drinks without the negative side effects linked to artificial sweeteners and refined sugars.
However, whole-leaf stevia or crude stevia extracts have not been permitted for sale as sweeteners in the United States because there is not enough toxicological information on these products, according to the FDA.
That said, while the “natural” stevia plant products that you see lining grocery store shelves — such as Stevia in the Raw and Truvia — are initially extracted from the leaves of the Stevia Rebaudiana plant, by the time they hit your coffee, they are actually a highly processed stevia blend.
Healthline explains, “They’re made using rebaudioside A (Reb A) — a type of refined stevia extract, alongside other sweeteners like maltodextrin and erythritol. During processing, the leaves are soaked in water and passed through a filter with alcohol to isolate Reb A. Later, the extract is dried, crystallized, and combined with other sweeteners and fillers.”
These stevia sweeteners are also 300 times sweeter than sugar. While they can contribute sweetness to foods and beverages without adding any extra calories, they potentially pose some of the same health risks as artificial sweeteners do when they overstimulate your taste buds with daily intake; however, more evidence is needed to back up this claim.
So, What Now?
It’s important to remember that food marketed as sugar-free isn't always calorie-free. And even when it is, the risks hardly seem worth the reward.
Natural sugar substitutes like agave nectar may seem healthier than sugar, but Mayo Clinic explains that their vitamin, antioxidant and mineral content isn't significantly different. For example, honey, maple syrup, and sugar are nutritionally similar, and your body processes all of them into glucose and fructose.
Dr. Ludwig explains it’s all in how it’s packaged: “Sugar-containing foods in their natural form, whole fruit, for example, tend to be highly nutritious—nutrient-dense, high in fiber, and low in glycemic load.”
Maybe sugar is the way to go after all!