|Beware: Splenda(R) is not sucralose, but 95% dextrose (D-glucose) and + maltodextrin combined with an undisclosed small amount of mostly indigestible sucralose.|
The mainstream interpretation of Wang's results says that the researchers show (for the first time] that chronic consumption of the synthetic sweetener sucralose causes increased food intake... what the study doesn't highlight and corresponding media articles try to mention at best in parts the average reader will often skip is the fact that the "subjects" were not humans, not pigs, not even mices, but our close relative *ahm*, the fruit flies.
|Figure 1: Food intake in fruit flies that are chronically exposed to high dose sucralose (Wang. 2016).|
|Figure 2: Food intake in rodents who received a jelly with the human equivalent of 3.2g sucralose - that's up to 3.2x sweeter than a full kilogram of sugar (Wang. 2016).|
This is not only significantly more than the only existing government recommendation of the Canadian Diabetes Association considers safe (namely 9 mg/kg BW/day).It is also the amount of sucralose in 80 splenda-sweetened diet cokes at 40mg sucralose per can (Franz. 2010), hilarious amounts of SPLENDA®, which contains only relatively small amount of sucralose and is mostly made from dextrose or highly fluffed maltodextrin, "bulking agents" that give SPLENDA® its volume. Even if we combine all sources of sucralose in our diet and assume an "aggressive replacement of sugar" (Grotz. 2009), the predicted daily intake of 1.3 mg/kg body weight/day for the average adult is significantly lower than the 40mg/kg human equivalent of the amount of this sweetener that was used in the rodent experiment of the study at hand.
"Through systematic investigation of this effect, we found that inside the brain's reward centres, sweet sensation is integrated with energy content. When sweetness versus energy is out of balance for a period of time, the brain recalibrates and increases total calories consumed. In the study, fruit flies that were exposed to a diet laced with artificial sweetener for prolonged periods (more than five days) were found to consume 30 percent more calories when they were then given naturally sweetened food. When we investigated why animals were eating more even though they had enough calories, we found that chronic consumption of this artificial sweetener actually increases the sweet intensity of real nutritive sugar, and this then increases the animal's overall motivation to eat more food" (University of Sidney. 2016)Eventually, it is thus the mismatch between the sweetness of an ingested substance and its nutritional value, which is at the heart of the problem. Food that contains synthetic sweeteners such as sucralose obviously don't show a correlation between their sweetness and their energy contemt... and that's not news: neither in science, nor here on the SuppVersity where I've previously pointed out that the use of artificial sweeteners may make your sweet tongue even sweeter and thus worsen your ability to stay away from or at leat control the intake of sweets efficiently.
What the press release don't tell you about the practical (in)significance of the results
What is news, however, is that Wang et al. appear to have finally identified the mechanism behind the appetite-stimulating effect of consuming synthetic sweeteners: a conserved neural fasting response, which response integrates pathways that govern feeding, gustatory reward, and energy sensing that together modify how sweet food is perceived. Accordingly, the downstream effects are similar to that of fasting: a compensatory response is activated that alters taste sensitivity and feeding behavior accordingly and we start to eat more. Now this wouldn't be a problem if we stuck to the same artificially sweetened products. Unfortunately, the anti-satiety effects extend whey beyond certain foods and into the realms of everything sweet (probably including starches, as well).
- Franz, Mary. "Diabetes Self-Management, Diet Soft Drinks". 2010
- Grotz, V. Lee, and Ian C. Munro. "An overview of the safety of sucralose." Regulatory toxicology and pharmacology 55.1 (2009): 1-5.
- University of Sidney. "Why artificial sweeteners can increase appetite." 13 July 2016 < http://sydney.edu.au/news-opinion/news/2016/07/13/why-artificial-sweeteners-can-increase-appetite.html >
- Wang, Qiao-Ping, et al. "Sucralose Promotes Food Intake through NPY and a Neuronal Fasting Response." Cell Metabolism 24.1 (2016): 75-90.