Artificial sweeteners: are they helping you lose weight or gain it?

Danielle Pavliv and Laura Gottschalk, PhD

Updated 2016

When people want to treat themselves to something sweet without having to treat themselves to a larger pants size too, they often reach for low-calorie, artificial sweeteners. But do artificial sweeteners actually help you to lose weight?   The answer is yes.  And are they safe?  We need to know more.

What are artificial sweeteners?

The most popular types of sugar substitutes in the US and many other countries are artificial sweeteners. Artificial sweeteners are typically made in a laboratory and don’t contain calories or supply your body with energy, vitamins, or anything else nutritious. These sweeteners are many times sweeter than sugar, so less is needed to reach the same level of sweetness as something containing sugar. Sweeteners can be used in the home for baking and cooking, and they can also be found in many processed food products including soft drinks, candy, and canned foods.

There are six types of artificial sweeteners currently approved by the FDA.

Two new “natural” sugar substitutes have also been approved by the FDA. Brand names such as Truvia, PureVia, Enliten (Steviol glycosides) and Nectresse, Monk Fruit in the Raw, PureLo (monk fruit extract) are all made from plants. But before being sold in the store, they must first be highly processed in a laboratory. So don’t be fooled into thinking that the word “natural” means that it comes straight from nature to your table.

Do artificial sweeteners help you lose weight?

It makes sense that eating and drinking fewer calories by switching to sugar substitutes should lead to weight loss. Yet, a lot of people have heard the rumor that consuming artificial sweeteners— mainly in drinks—can actually cause you to gain weight. This idea comes from several studies that found that people who drink diet drinks weigh more than those who don’t 1. However, people who drink diet sodas may be more likely that others to be trying to keep their weight down, or they may indulge themselves by eating more high-calorie foods since they “saved calories” with their diet soda.

A better way to study if artificial sweeteners  help people lose weight is known as a randomized controlled trial. People in the trial are randomly put into groups—one group uses artificial sweeteners while the other group uses sugar. Then, the two groups can be compared to see if using sweeteners resulted in a change. Randomized controlled trials show modest but significant decreases in weight, BMI, and waist size for people who switched from sugary drinks to artificially sweetened ones 2. These studies support the idea that artificial sweeteners can help you lose weight.

Are artificial sweeteners safe?

For many years, there have been concerns about whether artificial sweeteners cause cancer. Studies in the 1970s that showed that Saccharin (Sweet’N Low) caused bladder cancer in lab rats 3. Since then, other studies have also shown a link between high doses of certain artificial sweeteners and cancer in rodents 4.

But, mice are not men (or women).  Experiments using mice and rats give us hints at what might happen in humans, but they’re not always correct. For example, the bladder cancer seen in the lab rats from Sweet’N Low was specific to rats because of their urine, which is different than human urine 5. The National Cancer Institute states that no well-conducted scientific studies have shown that any of the FDA-approved artificial sweeteners cause cancer in humans.

In addition to cancer fears, you may have heard some of the other negative health claims about artificial sweeteners including that they could change hormone levels 6, increase the risk of heart problems 7, and cause higher rates of type II diabetes 8.  It is difficult to conduct a study to find out if any of these are true, and so far no study has had conclusive evidence that it can cause cancer.  We don’t really know what the impact is of a lifetime of using these artificial sweeteners is, however.  More research is needed for the older artificial sweeteners as well as the newer sweeteners, such as Splenda, which haven’t been around as long.

Should you use artificial sweeteners?

The Center for Science in the Public Interest (CSPI) recommends using caution with most artificial sweeteners, or avoid certain ones completely (see CSPI’s full recommendation here).  But we agree with CSPI that, “for most Americans, the increased risks of obesity, diabetes, and heart disease from consuming sugar drinks probably outweigh the risks posed by artificial sweeteners.”  And, it seems clear that—when paired with a healthy diet and exercise—using artificial sweeteners to replace sugar can be one part of achieving your weight goals. Just keep in mind that you shouldn’t consumer more calories in other food because you “saved” some by drinking a diet soda!

  1. Anderson GH, Foreyt J. Sigman-Grant M, Allison DB, The use of low-calorie sweeteners by adults: impact on weight management. J Nutr. 2012 Jun;142(6):1163S-9S.  
  2. Rogers PJ, Hogenkamp PS, de Graaf C, et al. Does low-energy sweetener consumption affect energy intake and body weight? A systemic review, including meta-analysis, of the evidence from human and animal studies. Inter J of Obesity. 2016 Mar;40(3):381-94.  
  3. Arnold DL, Moodie CA, Stavric B, Stoltz DR, Grice HC, Munro IC. Canadian saccharin study. Science. 1977;197:320.  
  4. Soffritti M, Padovani M, Tibaldi E, et al. Sucralose administered in feed, prenatally through lifespan, induces hematopoietic neoplasias in male swiss mice. Int J Occup Environ Health. 2016 Jan;22(1):7-17.  
  5. Tandel KR. Sugar substitutes: health controversy over perceived benefits. J Pharmacol Pharmacother. 2011;2:236-243.  
  6. Brown RJ, Walter M, Rother KI. Effects of diet soda on gut hormones in youths with diabetes. Diabetes Care. 2012 Mat;35(5):959-64  
  7. Vyas A, Rubenstein L, Robinson J. et al. Diet drink consumption and the risk of cardiovascular events: a report from the Women’s Health Initiative. J Gen Intern Med. 2015 apr;30(4):462-8.  
  8. Suez J, Korem T, Zeevi D, et al. Artificial sweeteners induce glucose intolerance by altering the gut microbiota. Nature. 2014 Oct 9;514(75210:181-6.