The Great Diet Soda Weight Loss Hoax: What You Should Know

diet soda bad for weight loss

Many of us struggle to maintain a healthy weight. In fact, the Centers for Disease Control and Prevention (CDC) estimates that over 70 percent of American adults age 20 years or older are overweight or obese. Maybe this is why people look for anything and everything that may help in losing weight- including drinking diet pop instead of the regular kind. After all, products claiming to be “diet” or “sugar free” or “zero calorie” must be good for waistlines, right? The truth, shockingly enough, is the opposite. So why is diet soda bad for weight loss?

A recent study actually suggested that drinking diet pop could be more effective than water alone when it comes to losing weight. So with that said, should we celebrate with our favorite diet beverages? Before we raise our glasses and say “cheers,” let’s look at the research.

The study, published in Obesity, included approximately 300 overweight participants. All of these participants were enrolled in a weight loss and exercise program. As part of the study, each individual was randomly assigned to one of two groups. The first group was told to avoid all diet drinks and drink mostly water. The second group was told to consume a combination of zero-calorie drinks (e.g., diet pop or artificially sweetened teas) and water. After three months, those in the diet-drink group had lost about 13 pounds on average, four more than the average of nine pounds shed by participants in the water group.

Seems like a victory for diet pop, right? Well, maybe not so fast. Here are some of the reasons why we should be at least a little skeptical:

At the start of the study, one of the stipulations was that all those participating be routine diet pop drinkers. The protocol required several diet sodas per week at a minimum.

The group assigned to diet pop could also drink all the water they wanted, while the group assigned to water could not drink any diet sodas (or any drink containing an artificial sweetener).

Details of what these groups ate were left out of the study. Dietary intake in a study like this is a critical piece of information.

The study was funded by the American Beverage Association (including two paid consultants from Coca-Cola), which left the potential for bias.

Other researchers contended that this particular study didn’t provide any closure to the questionable science of diet sodas. They found the study didn’t reveal anything about the long-term health consequences of diet pop, which should be the primary focus.

Why Diet Soda Is Bad for Weight Loss

weight loss scale

So if diet sodas were once thought to be the ideal solution to sugar-filled, calorie-laden drinks, why are they now bad? They taste great and have zero calories, so it seems like a win-win for everyone. Again, there’s more beneath the surface of these popular, over-promising beverages.

Whether you decide to indulge in diet pop, like anything else, is your personal choice. It’s important to note, however, that research has shown that the artificial sweeteners contained in these beverages can cause you to eat more. Artificial sweeteners are designed to be very sweet (ranging from 600 to 1,300 times as sweet as sugar), and therefore, may feed and/or grow your “sweet tooth.”

Studies have suggested that artificial sweeteners trick our bodies, throwing off our internal ability to count calories. Research from Purdue University’s Ingestive Behavior Research Center revealed that rats given “no-calorie” sweetener actually ate more, and gained more weight and body fat than rats that ate standard table sugar. The investigators reasoned that the artificial sweetener tricked the rats’ brains into thinking they’d be consuming more calories (our body will naturally register sweetness and come to understand that very sweet things contain a lot of calories). When the calories didn’t come, the metabolisms of the rats changed and had trouble regulating appetite, making them want to eat more.

More Evidence That Diet Soda Is All Gain and Little Weight Loss

soda can

Another study published earlier this year in the Journal of American Geriatrics Society also reported that individuals who consumed diet pop gained almost triple the abdominal fat over nine years compared to those who didn’t drink diet soda. People who didn’t drink diet pop gained about 0.8 inches around their waists over the study period, while those who drank diet soda gained 3.2 inches. Occasional drinkers of diet pop gained approximately 1.8 inches.

This change in waistlines is concerning because it stresses this truth: the belly is a bad place to store extra pounds. Fat cushioning the abdominals from the inside and wrapping around the inner organs (called visceral fat) has been linked with increased heart disease, inflammation and type 2 diabetes.

Along with the above examples, additional research has also shown that artificial sweeteners changed the gut bacteria of mice, which made them more susceptible to insulin resistance and glucose intolerance (both can lead to weight gain). These sweeteners have been associated with a drop in leptin, an appetite-regulating hormone, as well. Leptin inhibits hunger.

Other Reasons to Skip The Diet Soda

crushed soda can

Most diet pop is loaded with artificial sweeteners and chemicals that may be harmful to your body. Most of these sweeteners are approved by the Food and Drug Administration (FDA), but for the past few decades, scientists have examined the effects of them on both animals and humans. Some of this research has shown no harmful effects to humans, while others have uncovered possible links to cancers, tumors, thyroid issues and weight gain (mostly in laboratory rats).

A University of Minnesota study found that drinking one diet pop a day was associated with a 36 percent increased risk of metabolic syndrome and diabetes. Metabolic syndrome encompasses a group of conditions (such as high blood pressure, high blood sugar and high cholesterol) that put individuals at greater risk for heart disease, stroke and diabetes.

Diet pop may have zero (or few) calories, but it also has zero nutritional value.

Aspartame (one artificial sweetener) has been linked with triggering headaches in some people (including migraine headaches).

Citric acid found in pop can weaken and destroy tooth enamel over time, ruining your smile.

One study presented at an American Academy of Neurology meeting found that over a decade, people who drank more than four cups or cans of pop a day were 30 percent more likely to develop depression than those who avoided sugary drinks. (This study included both regular and diet pop.)

Female cola drinkers had nearly 4 percent lower bone-mineral density in their hips than women who didn’t drink pop, according to a Tufts University research study. Low bone-mineral density places you at greater risk for osteoporosis, which often leads to broken bones.

According to researchers from the University of Miami and Columbia University, one diet pop per day could elevate your risk of having a stroke, heart attack or another life-threatening vascular event. This study showed that routine diet pop drinkers were 43 percent more likely to have had a vascular event than those who never drank diet soda.

The Best Beverages to Help With Weight Loss

Quitting diet (or regular) pop may not be fun or easy, but it really is best for your health. Below are some suggestions for a more healthful, flavorful beverage:

Plain old H2O is still the best for your body

glass of waterFlavored waters are readily available, but remember, many still contain sugar or artificial sweeteners. To flavor the natural way, add slices of fruits and veggies like lemons, oranges, cucumber, mint or lime to your water. You could even put chopped up fruit in an ice cube tray, add water and then freeze. Place these cubes in your water for boosted flavor and color.


Go for some green tea

green teaGreen tea can help reduce the risk of several types of cancer, heart disease, high blood pressure, kidney stones and more. Green tea is calorie-free (without added milk or sugar) and naturally high in antioxidants as well.

Sparkle with sparkling water

sparkling water

Photo credit: waynemah via Foter.com / CC BY-NC-ND

Try a plain sparkling water with added cucumbers. oranges or other natural fruits/vegetables. You can also mix a tablespoon or two of an all-natural juice (e.g., cranberry or pomegranate) into your sparkling water for a kick of flavor. You’ll benefit from the antioxidants and vitamin C from the juice with no chemicals.

Consider a cup of coffee
cup of coffeeEvidence has shown that coffee in moderation can be a healthy part of your diet. So if you crave the caffeine found in pop, you might want to reach for a regular cup of joe instead. Coffee drinkers may have a lower risk of developing heart disease, type 2 diabetes and certain types of cancer. Bear in mind, too much caffeine can make you jittery and anxious, so don’t overdo it on the java.