Diet Soda May Do More Harm Than Good

Story at-a-glance

  • Despite being promoted for weight loss, foods and beverages with artificial sweeteners have never been proven to help weight loss. In fact, studies that look at this actually find people gain weight when they use them
  • A recent review of diet soda studies found that diet soda drinkers suffer the same health problems as those who opt for regular soda, such as excessive weight gain, type 2 diabetes, cardiovascular disease and stroke
  • The watchdog group The Center for Science in the Public Interest (CSPI) recently downgraded its safety rating of sucralose (Splenda) from "safe" to "caution," meaning it "may pose a risk and needs to be better tested”
  • The most comprehensive and longest human study looking at aspartame toxicity found a clear association between aspartame consumption and non-Hodgkin's Lymphoma and leukemia


This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.

By Dr. Mercola

Do you believe that drinking diet soda will allow you to “have your cake and eat it too” while still controlling your weight?

If so, you may be surprised to learn that research has repeatedly shown that artificially sweetened no- or low-calorie drinks and other “diet” foods actually tend to stimulate your appetite, increase cravings for carbs, and stimulate fat storage and weight gain.

Most recently, a report published in the journal Trends in Endocrinology & Metabolism1 highlights the fact that diet soda drinkers suffer the same exact health problems as those who opt for regular soda, such as excessive weight gain, type 2 diabetes, cardiovascular disease and stroke.2, 3

The authors—who were “shocked” at the results—looked at studies published in the past five years that examine the relationship between diet soda consumption and health outcomes:

“This paper discusses these findings and considers the hypothesis that consuming sweet-tasting but noncaloric or reduced-calorie food and beverages interferes with learned responses that normally contribute to glucose and energy homeostasis.

Because of this interference, frequent consumption of high-intensity sweeteners may have the counterintuitive effect of inducing metabolic derangements,” they wrote.

Dr. Sanjay Gupta discusses the report in the CNN video above, explaining that artificial sweeteners basically trick your body into thinking that it’s going to receive sugar, but when the sugar doesn’t arrive, your body signals that it needs more, which results in carb cravings. Most people give in to such signals and end up overeating on other foods and snacks.

Artificial Sweeteners Actually INCREASE Weight Gain

This connection between sweet taste alone and increased hunger can be found in the medical literature going back at least two decades. These two studies, for example, dating back to the late 80s and early 90s, both showed this link between artificial sweeteners and increased hunger:

  • Physiology & Behavior, 19884 – In this study, they determined that intense (no- or low-calorie) sweeteners can produce significant changes in appetite. Of the three sweeteners tested, aspartame produced the most pronounced effects.
  • Physiology & Behavior 19905 – Here, they again evaluated whether or not the mere taste of “sweet” increases hunger, by having human subjects chew gum for 15 minutes containing various levels of aspartame (0.05%, 0.3%, 0.5%, or 1.0%).

Interestingly, although those who chewed artificially sweetened gum reported increased hunger compared to the control group who were given nothing or unsweetened gum base to chew, the increase did not directly correlate with the aspartame concentration in the gum.

Women experienced the greatest increase in hunger after chewing gum containing 0.3 percent aspartame (the second lowest concentration amount), while men were the hungriest after chewing on gum containing 0.5 percent aspartame. The authors stated:

"The highest aspartame concentrations had a time-dependent, biphasic effect on appetite, producing a transient decrease followed by a sustained increase in hunger ratings. Thus, the concentration of the sweetener, the sex of the subject, and the time after chewing, were all important determinants of whether 'sweetness' increased hunger."

Why Doesn’t the FTC Sue Diet Makers for Fraudulent Advertising?

In a study6 of artificial sweeteners performed on college students, there was no evidence that artificial sweetener use was associated with a decrease in their overall sugar intake either. These results indicate that eating arti­ficial sweeteners simply perpetuates a craving for sweets, and overall sugar consumption is not reduced—leading to further problems controlling your weight.

In 2005, data gathered from the 25-year long San Antonio Heart Study7 also showed that drinking diet soft drinks increased the likelihood of serious weight gain – far more so than regular soda.8 According to Sharon Fowler, M.P.H:

“On average, for each diet soft drink our participants drank per day, they were 65 percent more likely to become overweight during the next seven to eight years, and 41 percent more likely to become obese.”

This finding supports a 2004 study9 at Purdue University, which found that rats fed artificially sweetened liquids ate more high-calorie food than rats fed high-caloric sweetened liquids. The researchers believe the experience of drinking artificially sweetened liquids disrupted the animals' natural ability to compensate for the calories in the food. A more recent review, published in June 2010 in the Yale Journal of Biology and Medicine,10 delves into the neurobiology of sugar cravings and summarizes the epidemiological and experimental evidence concerning the effect of artificial sweeteners on weight. The author states:

“Several large scale prospective cohort studies found positive correlation between artificial sweetener use and weight gain. …Preload experiments generally have found that sweet taste, whether delivered by sugar or artificial sweeteners, enhanced human appetite. Aspartame-sweetened water, but not aspartame capsule, increased subjective appetite rating in normal weight adult males…

Unlike glucose or sucrose, which decreased the energy intake at the test meal, artificial sweetener preloads either had no effect or increased subsequent energy intake. Those findings suggest that the calorie contained in natural sweeteners may trigger a response to keep the overall energy consumption constant. ...Increasing evidence suggests that artificial sweeteners do not activate the food reward pathways in the same fashion as natural sweeteners…

Natural and artificial sweeteners also activate the gustatory branch differently. …Lastly, artificial sweeteners, precisely because they are sweet, encourage sugar craving and sugar dependence. …Unsweetening the world’s diet may be the key to reversing the obesity epidemic.”

That last statement is probably the most accurate conclusion there is. Americans in particular are addicted to sweet flavors, which appears to trigger a complex set of biological systems, pathways, and mechanisms that in the end leads to excess weight gain whether that flavor comes loaded with calories or not. In the end, the research tells us that artificial sweeteners are nothing more than a pipe dream when it comes to being a dieter’s aid, because contrary to what the marketing campaigns claim, low- or no-calorie artificial sweeteners are more likely to help you pack on the pounds than shed them.

What Dr. Gupta Failed to Tell You About the Dangers of Aspartame

This hypothesis was also demonstrated in a 2012 study published in the journal Appetite,11 which showed that saccharin and aspartame both cause greater weight gain than sugar. Rats were fed plain yogurt sweetened with either aspartame, saccharin, or sugar, plus their regular rat chow, for 12 weeks.

“Results showed that addition of either saccharin or aspartame to yogurt resulted in increased weight gain compared to addition of sucrose, however total caloric intake was similar among groups,” the researchers write.12

The reason for the similar calorie consumption between the groups was due to increased chow consumption by the rats given artificially sweetened yoghurt. This type of compensation has been found in previous studies13 as well, indicating that when your body gets a hit of sweet taste without the calories to go with it, it adversely affects your appetite control mechanisms, causing increased food cravings. That’s all good and well, and mounting research appears to support this “metabolic derangement” hypothesis.

However, Dr. Gupta falls short when it comes to the overall health hazards of artificial sweeteners—completely dismissing the inherent toxicity of artificial sweeteners like aspartame. He even claims that there’s “no evidence of a link” between aspartame and cancer, stating that aspartame has been on the market since the 60’s and no such link has been shown in the 40 years since. I guess it’s really a matter of looking at the available evidence.

Not only have studies showing a cancer link been published in recent years, but during our 40-year long “war on cancer,” cancer rates have in fact increased despite scientific advances in treatment, and now surpass heart disease as the number one killer of Americans under the age of 85.14 The reason for this is still under debate, as no particular industry wants to take responsibility for their contribution to toxic overload in the population at large...In my view however, I believe it is irresponsibly negligent to flatly ignore the potential impact of artificial sweeteners on our skyrocketing disease rates. Telling people to consume a toxic agent “in moderation” is just not good advice in my opinion.

As for the potential cancer link, one lifetime feeding study published in 201015 found that aspartame induced cancers of the liver and lung in male mice. It was also carcinogenic in male and female rats. Another study of great importance was published just last year. It’s the most comprehensive and longest human study— spanning 22 years — that has ever looked at aspartame toxicity. The study evaluated the effect between aspartame intake and cancer, and they found a clear association between aspartame consumption and non-Hodgkin's Lymphoma and leukemia.

Recent research has also demonstrated that aspartame worsens insulin sensitivity to a greater degree than sugar, which is quite the blow for diabetics who obediently follow the recommendation to switch to diet sodas to manage their condition. The researchers used a dosage of aspartame that approximates the ADI for aspartame in the US (approx. 50 mg/kg body weight), and not only was aspartame found to decrease insulin sensitivity compared to controls, it also wrought havoc on brain function.

CSPI Downgrades Splenda Safety Rating from 'Safe' to 'Caution'

In related news, the watchdog group The Center for Science in the Public Interest (CSPI) recently downgraded its safety rating16, 17 of sucralose (Splenda) from "safe" to "caution," meaning it "may pose a risk and needs to be better tested."

“In what might be the greatest cause for concern, in 2012 an independent Italian laboratory announced (but has not yet published) a study that found that sucralose caused leukemia in mice that were exposed from before birth. That was the same lab that several years earlier published studies indicating that aspartame caused cancers in rats and mice,” CSPI writes.

Unfortunately, CSPI also proves to be seriously confused on this issue by recommending that you opt for diet soda over regular soda because “[r]egular soda poses the greater and demonstrable risks of obesity, diabetes, heart disease, gout, tooth decay, and other health problems." As discussed above, this is incorrect, as studies are in fact showing that diet soda is equal to or worse than regular soda when it comes to promoting weight gain and chronic disease.

Why 'FDA Approved' Tells You Virtually Nothing About a Product’s Safety...

As discussed by Dr. Janet Hull,18 many tend to excuse the negative health effects of aspartame simply because it has received the stamp of approval by the Food and Drug Administration (FDA).

“[T]his may not be something the American consumer can actually depend upon anymore,” she writes, because “[t]he FDA rules and regulations for the approval of food additives... it has some serious flaws.”

In her article, Dr. Hull talks about Beth Hubrich, president of the Calorie Control Council, and how FDA's requirement that the industry do its own research actually puts the industry in the hot seat of proving the flaws of their own products. Clearly, this is a strong disincentive to finding anything wrong, since any company applying for approval wants their product to reach the market. In a nutshell, the FDA trusts corporations to be completely honest and above board about their own research findings—with billions of dollars of profits hanging in the balance! How likely do you think it is that such a system will actually ensure that each product released to market is in fact safe? This is the classic example of the fox guarding the hen house.

“Basically, all the FDA is responsible for is reviewing the summaries of research conducted by the company applying for approval, typically from scientific studies the applicant has pay-rolled. Then, the company presents their reasons why their product should be allowed in the public food supply based on their research. At the very least, the research reports are controversial, and rarely reviewed by independent researchers not related to the industry,” she writes.

Beth Hubrich, a spokeswoman for the industry group Calorie Control Council, has spent years disputing the results from independent researchers that find fault with artificial sweeteners. This despite the fact that an independent researcher has far less incentive to come to any particular conclusion—good or bad... As I’ve discussed in a previous article, the Calorie Control Council is an association that represents manufacturers and suppliers of low-calorie, sugar-free and reduced sugar foods and beverages, and has strong ties to the Kellen Company, which is instrumental in creating and managing industry front groups specifically created to mislead you about the product in question, protect industry profits, and influence regulatory agencies. This makes virtually any position of the Calorie Control Council questionable at best when it comes to public safety.

Are You Addicted to Artificial Sweeteners?

Artificial sweeteners tend to trigger enhanced activity within your brain's pleasure centers, yet at the same time provide less actual satisfaction. This separation of the taste of sweetness from caloric content means that when you consume artificial sweeteners, your brain actually craves more of it because your body receives no satisfaction on a cellular level by the sugar imposter. This can actually contribute to not only overeating and weight gain, but also an addiction to artificial sweeteners, along with an increased risk of type 2 diabetes, heart disease and stroke—even if your weight is normal.

In order to break free, be sure you address the emotional component of your food cravings using a tool such as the Emotional Freedom Technique (EFT). More than any traditional or alternative method I have used or researched, EFT works to overcome food cravings and helps you reach dietary success. If diet soda is the culprit for you, be sure to check out Turbo Tapping, which is an extremely effective and simple tool to get rid of your soda addiction in a short amount of time.

If you still have cravings after trying EFT or Turbo Tapping, you may need to make some changes to your diet. My free nutrition plan can help you do this in a step-by-step fashion. If you’re searching for a safer sweetener option, you could use stevia or Lo Han, both of which are safe natural sweeteners. Remember, if you struggle with high blood pressure, high cholesterol, diabetes or extra weight, then you have insulin sensitivity issues and would likely benefit from avoiding ALL sweeteners.

Last but not least, if you experience side effects from aspartame or any other artificial sweetener, please report it to the FDA (if you live in the United States) without delay. It's easy to make a report — just go to the FDA Consumer Complaint Coordinator page, find the phone number for your state, and make a call reporting your reaction.


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