A review of the literature from Nature’s International Journal of Obesity looked at studies involving artificial sweeteners. They call them “Low energy Sweeteners” or LES. Artificial sweeteners they investigated were aspartame, stevia, and sucralose.
The Great Evil and Pseudoscience
Since the word “artificial” has been in the US vernacular it has been used to demonize the sweeteners. Because of the rumors and rabid posts about how various artificial sweeteners cause damage is widely distributed and incorrect. This study didn’t address those issues, but did address some of the fundamental questions about the use of artificial sweeteners and its usefulness for weight loss or sustaining weight loss.
Drinking Liquid Calories
Weight loss surgeons for years have been telling patients to not drink their calories, unless they are in an immediate post operative state, or they need supplemental proteins because a part of their anatomy is bypassed.
There are those patients who come to us drinking 12 cans of cola a day (about 1680 calories a day from liquids). Trading those liquid calories seems like it should reduce several pounds a week, but it never works out that way.
Obesity is more than calories in and calories out. That simple explanation never works, as it is not only the calories one eats (or drinks) but also what the body does with the calories – both in terms of absorption and processing. It is also how well the body utilizes fat stores and cravings.
Do Artificial Sweeteners Increase Intake of Other Calories
The concern has been that artificial sweeteners increase total caloric intake. Some evidence has been found that people will compensate and eat more calories when drinking. There have been several theories as to why this may be, or if it is simply correlation and not causation.
There has been some concern that the sugar receptors in the gut react to artificial sweeteners by increasing insulin, and thus decreasing blood sugar that increases appetite. However, if those incretins did cause a bump in insulin that was not countered by dietary sugar the body could always compensate by freeing up more glycogen stores. It is a theory, never proven, but a theory.
Other concerns about artificial sweeteners include the increase in the sweet taste of the palate may cause an increase in other foods either because of compensation (I had diet coke so I can eat larger fries) or because of a drive to balance the flavor of the food. There is evidence that the palate likes to have a balance in flavors, although most of the palate of America appears to be geared to higher sugars, fats, and salts that is otherwise recommended.
What Do Animal Studies Tell Us
They reviewed a number of studies from rodents. The disadvantage of rats and mice are that they do not respond the same way that humans do when given artificial sweeteners. A human, when given sweetener, will have an increase in blood sugar after eating something sweet – a rat will not. Suffice to say, there are other differences between rats and most humans.
Most studies showed that long-term consumption of artificial sweeteners did not lead to an increase in the rats body weight. In some cases where the sweeteners may have increased the palatability of the diet was there an increase in body weight. I am not certain how you ask a rat about the kibble, but the rat whisperer has their ways (they also talk to lawyers).
Intermittent exposure to a diet that had sweetener, along with non-sweetened food led to an increase in body weight compared with those diets that had glucose alone as a sweetener. This result was replicated in other studies with rats, but not with people. So it is interesting, but the significance of this is not known. Rats do have a sweet tooth – in fact, better to put something sweet in a rat or mouse trap than cheese. Again – unless we compare rats and lawyers, these studies have unknown value to humans.
Rat studies are great for headlines, but whether they really tell us what happens with humans or not is a wide open question.
Human Studies with Artificial Sweeteners
There are two types of studies that were compiled in this review one were observational or cohort studies. In evidence-based medicine cohort studies are considered level 3 studies – meaning they are better than an expert opinion or case-controlled studies but not as reliable as controlled trials or randomized trials.
Cohort Human Studies
The results from the cohort studies were not consistent. Some studies showed lower risks of obesity with consumption of sweeteners and other studies showed there were higher risks. Since some of the studies relied on recall, it is impossible to determine with accuracy the food intake. Since obesity and consumption of diet beverages is high, it is odd there is no great results from this.
In small studies done with children and adults consumption of artificial sweeteners instead of sugar reduced short-term energy intake. In some studies the use of artificial sweeteners led to reductions in the body weight more than water. While no one should be surprised that energy intake and body weight goes down with sweeteners compared to sugar, that the sweeteners led to some more weight loss than water was surprising (about 126 calories per day – not much but still real).
The problem is that the intervention was with small amounts of artificially sweetened drinks- not the larger sizes commonly found in todays fast-food and chain restaurants.
There is clearly an advantage of drinking diet drinks vs drinking sugar drinks.But there is plenty of empiracal evidence to abandon diet drinks. While I enjoy the occasional diet Pepsi after playing a round of golf, and am sad it is no longer made with aspartame, it is a once a week thing. When people told me aspartame was used to kill ants, I tried it—it didn’t work (another urban myth).
This flies in the face of wild extrapolations about the issues with diet drinks. What I tell patients is simply this: artificially sweetened foods may change the microbiome of the gut (still a big black box) in rats – and maybe in humans. What is clear is that the more you eat sweet things, and develop a taste for sweet things, the easier it is to fall into sugar filled items that caused you to be my patient. It is also easy to eat more food to get that sweet taste out of your mouth — we call that balance. People who drink more artificial beverages tend to eat more food.
Instead of drinking the artificially sweetened anything I advise my patients to get off the sugar substitutes entirely. Why have your mouth addicted to the sweet taste.
International Journal of Obesity: 10 November 2015 Does low-energy sweetener consumption affect energy intake and body weight? A systematic review, including meta-analyses, of the evidence from human and animal studies. P J Rogers, P S Hogenkamp, et. al.
Dr. Terry Simpson
Dr. Terry Simpson received his undergraduate and graduate degrees from the University of Chicago where he spent several years in the Kovler Viral Oncology laboratories doing genetic engineering. He found he liked people more than petri dishes, and received his MD. Dr. Simpson, a renowned weight loss surgeon, is a leading advocate of culinary medicine. A frequent contributor to media outlets discussing health related topics and advances in medicine, he is also a proud dad, husband, author, cook, and surgeon “in that order.” For media inquiries, please visit www.terrysimpson.com.