In recent decades, there has been speculation about whether artificial sweeteners cause cancer. These rumors stem from studies in the 1970s linking saccharin, a type of artificial sweetener, to bladder cancer in lab rats. However, research has shown that due to genetic differences between rats and humans, these sweeteners are not carcinogenic to humans. The National Cancer Institute states that no sound scientific studies have shown that any of the FDA-approved artificial sweeteners cause cancer or any other serious health problems. In addition, a European researcher conducted a toxicological evaluation of the most popular sugar substitutes earlier this year. He examined all of the artificial sweeteners currently approved by the FDA as well as cyclamate, which is approved by the European Union and is pending approval in the United States. The researcher found that all of the discussed sweeteners are safe so long as people don’t consume too much but stick to the acceptable daily intake, or ADI.
So, this all sounds like good news, right? Unfortunately, recent research suggests that these sweeteners may not help people control their weight. In fact, they may even be associated with weight gain.
What are sugar substitutes?
Sugar substitutes are anything that can be used to sweeten food or drinks other than table sugar (sucrose). There are several different types of sugar substitutes commonly used. Artificial sweeteners are typically synthetic (made in a laboratory) and non-nutritive, which means they don’t contain calories and don’t supply your body with energy, vitamins, or anything beneficial to your body. A teaspoon of sugar contains about 16 calories, so people trying to maintain or lose weight often turn to artificial sweeteners to satisfy their sweet tooth. Sugar alcohols, such as sorbitol, maltitol and xylitol, and natural sweeteners, such as honey, on the other hand, usually do contain calories.
The most popular types of sugar substitutes in the US and many other countries are artificial sweeteners. These synthetic substitutes are many times sweeter than sugar, so less is needed to obtain the same level of sweetness as something containing sugar. They can also intensify and prolong flavors, which is why you may find that the flavor of artificially sweetened chewing gum lasts longer than sugar-sweetened gum. Sweeteners can be used in the home for baking, and they can also be found in many processed products including soft drinks, candy, and canned foods. They are becoming more popular as tabletop sweeteners at home and are available at nearly all restaurants and food chains to put in coffee and tea.
There are five types of artificial sweeteners currently approved by the FDA. The brand names, which you may better recognize, are in parentheses:
- Sucralose (Splenda)
- Aspartame (Equal, NutraSweet)
- Saccharin (Sweet’N Low)
- Acesulfame potassium (Sunett, Sweet One)
Some sweeteners are approved in other countries but not in the United States.
- Cyclamate, which is approved in the European Union, was banned by the FDA in 1969 after an animal study suggested it may be carcinogenic. However, the FDA later ruled in 1984 that evidence is lacking that cyclamate is dangerous to humans. It is currently pending re-approval in the United States.
- Alitame is a dipeptide similar to aspartame, but it is 10 times sweeter and has no aftertaste. Danisco, the company that owns the rights to alitame, recently withdrew its petition to the FDA for approval due to high production costs.
Similar to sucrose (what makes sugar sweet), sugar alcohols are carbohydrates, and they do contain calories. However, these alcohols are a hydrogenated form of carbohydrate and are usually much less caloric than regular table sugar. Sugar alcohols can often be found in processed foods like chocolate and baked goods, as well as in chewing gum and mouthwash. Even though sugar alcohols have calories, they don’t contribute to tooth decay because they are not metabolized by oral bacteria. Sugar alcohols can have laxative effects when consumed in large quantities, so it is important to use in moderation.
Commonly used natural sweeteners include honey, molasses, maple syrup and agave nectar. Most of these natural sweeteners contain either fructose (the kind of sugar found in fruit) or glucose (found in a variety of foods such as grains, fruits and vegetables), which are two types of simple sugars. Often, natural sweeteners are advertised as a healthier alternative to table sugar because they are not processed. However, most of these have just as many calories as sugar (if not more!), so they may not help with weight control.
One of the newest natural sweeteners in the U.S. is stevia, which comes from an herb from South America. Stevia has been used for centuries among indigenous people in South America, and it is gaining popularity in many other countries as well. While whole-leaf stevia is not approved for use in the U.S. due to concerns about its effects on the cardiovascular and reproductive systems, as well as the kidneys, the FDA approved stevia that has been highly refined in 2008. Refined stevia looks like sugar and is usually calorie-free. Stevia has been used as a dietary supplement to lower blood pressure and to regulate blood glucose levels, but more research is needed to determine its effectiveness for both of these cases.
Health benefits of artificial sweeteners
Artificial sweeteners do have several health benefits. If you chew sugar-free gum containing artificial sweetener, you don’t have to worry about your pearly whites. Artificial sweeteners don’t cause tooth decay, so they can help lower the risk of dental cavities. In addition, many of these sweeteners do not raise blood sugar levels because they are not carbohydrates. For this reason, they are popular with diabetics craving something sweet.
But do they help you maintain or lose weight?
So, is it too good to be true? Can you have your cake and lose weight too? Although artificial sweeteners are considered safe when consumed in normal quantities, research shows they may not help you stay thin. Numerous studies using various techniques have been conducted in recent years, and the findings may surprise you.
A study published in 2008 by Sharon Fowler and colleagues at the University of Texas Health Science Center at San Antonio followed people for up to 8 years to see if there was a link between weight gain and what beverages they drank.  They found that those who drank diet soda were more likely to gain weight than those who did not drink any soda. Normal-weight people who consumed more than 21 artificially sweetened soft drinks a week were almost twice as likely to become overweight or obese as normal weight people who did not drink soda of any kind.
A 2008 study by Susan Swithers and Terry Davidson of Purdue University found that rats fed the artificial sweetener saccharin consumed more calories and gained more weight than rats fed glucose, a type of simple sugar.  In addition, the rats fed the artificial sweetener regularly burned fewer calories through exercise. Why? Sweet tastes tell our bodies to expect calories, which are a form of energy. Rats used to consuming artificial sweetener “knew” that they weren’t going to get calories so they limited their movement and exercise to conserve calories. This suggests that regular use of artificial sweeteners can result in slower metabolism; excess calories are stored instead of burned, potentially leading to weight gain.
A study conducted by Erin Green and Claire Murphy of the University of California at San Diego in 2012 studied brain activity (using MRIs) in response to saccharin and sucrose when young adult diet and non-diet soda drinkers were given their preferred beverage after a 12-hour fast.  The researchers found that real sugar stimulates brain areas related to satisfaction, turning off the desire for more sweet food or drink and creating a sense of fullness. In people who regularly consume food and drinks containing artificial sweeteners, there is less stimulation in these areas of the brain, so they have more trouble feeling satisfied and will crave more sweetness.
Artificial sweeteners are trying to fool the body but the body, it seems, doesn’t like to be fooled. Tracy Hampton, a freelance medical writer, explains in the 2008 issue of the Journal of the American Medical Association that sweet taste induces an insulin response, but because artificial sweeteners don’t cause an increase in blood sugar, this results in hypoglycemia (or low blood sugar), giving the body and brain the signal to increase calorie intake by eating or drinking more. 
The research above suggests that artificial sweeteners may cause weight gain instead of weight loss, but this is a fairly new area of research and the findings are not conclusive. As pointed out in a 2012 study by Harvey Anderson and colleagues that was published in the Journal of Nutrition, the people participating in these studies were not randomly assigned to consume or not consume artificial sweeteners.  The studies looked at people who already used or didn’t use sugar substitutes, so it’s possible that confounding factors interfered with the results. For example, people who drink diet sodas may eat or drink more high-calorie food as well. In other words, maybe there are differences between people who choose to drink diet soda and people who choose not to drink any soda, and that may explain differences in weight gain over time. Interestingly, the researchers found that people using low-calorie sweetener tended to eat more fruits and vegetables and less saturated fat and added sugars. This suggests that users of low-calorie sweeteners may be more knowledgeable about healthy eating and more conscious of their own eating habits, which should lead to less weight gain.
Although most of the studies were not randomly assigning artificial sweeteners, the rats who were assigned to consume the artificial sweetener are the ones who turned into overweight couch potatoes. That suggests that the artificial sweeteners may really be the problem, perhaps affecting metabolism.
Finding a healthy solution
If you like your food and beverages sweet, you’re probably wondering what to do. One the one hand, consuming too much sugar is harmful to your health; on the other, your favorite diet drinks and artificially sweetened snacks may be adding pounds instead of helping you drop them. Eating more fruit is one way to satisfy your sweet tooth. Although fruit contains sugar, it has numerous benefits-short-term and long-term: vitamins, fiber to help you feel full, and natural fructose that satisfies your body’s desire for sweetness.
Just because diet soda isn’t good for your waistline, doesn’t mean, though, that you should switch to regular soda. Each 12-ounce can of regular soda contains 160 calories without any health benefits! And, of course, for diabetics, artificially sweetened drinks and desserts are the safest option, since they won’t raise blood sugar. Most likely, having an artificially sweetened cookie or soft drink now and again isn’t the problem. The problem is always needing something sweet as a pick-me-up (physically and psychologically). Little by little, you can train yourself to crave differently. Besides eating fruit, you can use fruit juice (just a little) in water to give it some flavor and sweetness. After you get used to that, you can try substituting a squeeze of lemon, some mint, or adding some spice or flower-scented tea to your water. You may just find that these easy, low-cost drinks quench your thirst better. After all, sugar (real sugar, anyway) actually increases your thirst rather than satisfying it!
 Tandel, KR. Sugar substitutes: Health controversy over perceived benefits. Journal of Pharmacology and Pharmacotherapeutics. Oct-Dec 2011;2(4):236-243.
 Larsen, John Christian. Artificial sweeteners: A brief review of their safety issues. Nutrafoods. 2012;11:3-9.
 Bloomgarden, ZT. Nonnutritive sweeteners, fructose, and other aspects of diet. Diabetes Care. May 2011;34(5):46-51.
 Federal Register. Notice of withdrawal of petition. 20 June 2008;73(120):35142-35143. Retrieved at http://www.fda.gov/OHRMS/DOCKETS/98fr/E8-13998.pdf.
 New York Medical College. Notice to the U.S. Food and Drug Administation (FDA) that use of Rebiana (Rebaudioside A) derived from Stevia rebaudiana, as a Food Ingredient is Generally Recognized as Safe (GRAS). January 15, 2009. Retrieved at http://www.accessdata.fda.gov/scripts/fcn/gras_notices/grn000282.pdf.
 Ulbricht C, Isaac R, Milkin T, Poole EA, Rusie E, Grimes Serrano JM…Woods J. An evidenced-based systematic review of stevia by the Natural Standard Research Collaboration. Cardiovascular and Hematological Agents in Medicinal Chemistry. Apr 2010;8(2):113-127.
 Fowler SP, Williams K, Resendez RG, Hunt KJ, Hazuda HP, Stern MP. Fueling the obesity epidemic? Artificially sweetened beverage use and long-term weight gain. Obesity. 2008;16(8):1894-1900.
 Swithers SE, Davidson TL. A role for sweet taste: Calorie predictive relations in energy regulation by rats. Behavioral Neuroscience. Feb 2008;122(1):161-173.
 Green E, Murphy C. Altered processing of sweet taste in the brain of diet soda drinkers. Physiology and Behavior. May 2012.
 Hampton T. Sugar substitutes linked to weight gain. Journal of the American Medical Association. 2008;299(18):2137-2138.
 Anderson GH, Foreyt J, Sigman-Grant M, Allison DB. The use of low-calorie sweeteners by adults: Impact on weight management. The Journal of Nutrition. 2012;142(6):1163s-1169s.