Low-calorie sweeteners in foods and diet drinks can disrupt metabolism, and some experts have suggested that there use might cause diabetes and obesity . But other studies have found that consuming diet drinks and food has little impact on metabolism and weight gain.
A new study by Yale researchers published March 3 in the journal Cell Metabolism  looked closely at sugars and artificial sugars. Dr. Dana Small and her fantastic research group at Yale (https://news.yale.edu/2020/03/03/yale-study-may-help-resolve-bitter-debate-over-low-cal-sweeteners?) looked.
Our group at Princeton and U.F. showed that sugars and even fructose corn syrup  was self-administered by laboratory animals as if it was a drug of abuse . We also related such consumption to exercise or lack of exercise and weight gain .
Brownell and our Group went a step further by comparing soft drink beverage products to cigarettes concluding that soft drinks: sugar as cigarettes: nicotine . Small and her Yale University School of Medicine group found that study participants who drank fruit-flavored beverages sweetened with sucralose alone showed no changes in the brain or metabolic responses.
However, when the study volunteers drank sucralose-sweetened drinks plus a tasteless carbohydrate, they exhibited adverse changes in insulin sensitivity and decreased brain responses to sweet taste. The combination may be a cause or at least the major contributor to the rise in the incidence of type 2 diabetes and obesity.
Their study enrolled 45 volunteers between the ages of 20 and 45 who didn’t regularly consume low-calorie sweeteners. The sweeteners (LCS) were made into fruit-flavored beverages with added sucralose and fruit-flavored beverages with added table sugar for comparison.
All were healthy weight volunteers without metabolic dysfunction. Other than consuming seven drinks in the lab over two weeks, their diet or other habits stayed the same.
The investigators conducted studies on the volunteers before, during, and after the testing period, measured taste perception and did an oral glucose tolerance test to look at insulin sensitivity and carried out fMRI scans to look at changes in the brain in response to sweet tastes, as well as other flavors like salty and sour.
A parallel study focused on adolescents aged 13–17 years, but the trial was abruptly terminated by the investigators when they discovered that two of the adolescents in the sucralose-carbohydrate combination group exhibited skyrocketing fasting insulin levels.
According to Small , “The subjects had seven low-calorie drinks, each containing the equivalent of two packages of Splenda, over two weeks.” “When the drink was consumed with just the low-calorie sweetener, no changes were observed.
However, when this same amount of low-calorie sweetener was consumed with a carbohydrate added to the drink, sugar metabolism and brain response to sugar became impaired.” “Collectively, the findings from the two human studies refute the hypothesis that sweet uncoupling taste from caloric content causes metabolic dysfunction or decreases in the potency of sweet taste as a conditioned stimulus,” the team concluded.
“Rather, the results reveal that metabolic dysfunction, coupled with reduced central sensitivity to sweet taste, occurs when an LCS is repeatedly consumed with, but not without, a carbohydrate … they suggest that sucralose consumption alters the metabolism of simultaneously consumed glucose to produce harmful effects on metabolic health rapidly.”
Artificial sweeteners were initially invented as a sugar substitute to help people cut down on calories, reduce insulin resistance and obesity. Animal studies and human experience suggest that the effects of artificial sweeteners may do the opposite and cause metabolic syndrome and globesity.
Artificial sweeteners may change the host microbiome, decrease satiety, and increase caloric consumption and weight gain. The combination of LCS with carbohydrates is contributing to the incidence of type 2 diabetes and obesity “… the addition of LCSs to increase the sweetness of carbohydrate-containing food and beverages should be discouraged, and consumption of diet drinks with meals should be counseled against.
Small said, “Our findings suggest that it’s okay to have a Diet Coke once in a while, but you shouldn’t drink it with something that has a lot of carbs … If you’re eating French fries, you’re better off drinking a regular Coke or—better yet— water. This has changed the way that I eat and what I feed my son. I’ve told all my friends and my family about this interaction.”
The bottom line is that, at least in small quantities, individuals can safely drink a diet soda, but they shouldn’t add French fries. “This is important information, particularly for people with diabetes who shouldn’t consume sugars,” Small said .
Most recently, in a new study Small and her Yale Group review the existing animal and human study data that support a different model for a food reinforcement or reward. The point to the gut-brain relationships, the existence of subcortical body-to-brain neural pathways linking gastrointestinal nutrient sensors to the brain’s reward regions.
Consciously perceptible hedonic qualities appear to play a less critical role in food reinforcement than previously thought by experts. In this new model, gut-brain reward pathways bypass cranial taste and aroma sensory receptors and the cortical networks that give rise to flavor perception. These new pathways can reinforce eating, food choice, and dietary decisions .
Like Dan Small’s study on artificial sweeteners, many of the assumptions and theories we hold on to are not supported by actual data. Future science will help us understand eating, overeating, and eating disorders. Until then, we should keep an open mind.
One such recent study that comes to mind was recently reported by researchers from Australia, the United Kingdom, and the United States. This new study may explain why people are eating fast processed food or sugar-rich foods, they can’t seem to control their appetite, and they tend to overeat.
They found that eating highly processed foods like junk foods, which are part of the western diet, can impair the part of the brain tied to self-control. This may help us explain why and how junk or manufactured food stimulates its own taking, causes loss of control as if it was a drug of abuse, and induce overeating and weight gain .
Eating a high-fat, high sugar diet even for just a week causes changes to the hippocampus, a brain region responsible for emotions, learning, memory, and motivation. In the study, the team found that even if a person is slim and healthy, eating a western diet for a week has impacted brain function, making it difficult for people to control their appetites.
Also, it turns out, palatable food such as sweets, snacks, and chocolates become more desirable when they’re full. As a result, people find that they really can not resist overeating highly processed, high fat, and high sugar foods because these foods undermine brain control of overeating by a direct and negative impact on the part of the brain that is needed for self-control.
1. Pearlman M, Obert J, Casey L The Association Between Artificial Sweeteners and Obesity. Curr Gastroenterol Rep. 2017 Nov 21;19(12):64. doi: 10.1007/s11894-017-0602-9.
3. Bocarsly ME, Powell ES, Avena NM, Hoebel BG. High-fructose corn syrup causes characteristics of obesity in rats: increased body weight, body fat and triglyceride levels. Pharmacol Biochem Behav. 2010 Nov;97(1):101-6
4. Avena NM, Bocarsly ME, Hoebel BG, Gold MS.Overlaps in the nosology of substance abuse and overeating: the translational implications of “food addiction.”Curr Drug Abuse Rev. 2011 Sep;4(3):133-9.
5. Avena NM1, Bocarsly ME, Hoebel BG. Animal models of sugar and fat bingeing: relationship to food addiction and increased body weight.Methods Mol Biol. 2012;829:351-65. doi: 10.1007/978-1-61779-458-2_23.
9. de Araujo IE, Schatzker M, Small DM Rethinking Food Reward.Annu Rev Psychol. 2020 Jan 4;71:139-164. doi: 10.1146/annurev-psych-122216-011643. Epub 2019 Sep 27.
About the Author:
Mark S. Gold, M.D. served as Professor, the Donald Dizney Eminent Scholar, Distinguished Professor and Chair of Psychiatry from 1990-2014.
Dr. Gold was the first Faculty from the College of Medicine to be selected as a University-wide Distinguished Alumni Professor and served as the 17th University of Florida’s Distinguished Alumni Professor.
Learn more about Mark S. Gold, MD
The opinions and views of our guest contributors are shared to provide a broad perspective of eating disorders. These are not necessarily the views of Eating Disorder Hope, but an effort to offer a discussion of various issues by different concerned individuals.
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Published on March 13, 2020.
Reviewed & Approved on March 13, 2020, by Jacquelyn Ekern MS, LPC
Published on EatingDisorderHope.com