Is Diet Soda Derailing Your Weight Loss Efforts?

Kelowna Gyms - One Life Fitness - Can of Coke Zero

Tips & Advice from the professional personal trainers at OneLife training gym in Kelowna.

I read an interesting study from the Journal of Physiology & Behavior that caused me to pause for a second and further re-evaluate my already shaky love affair with Diet Coke. Worse yet, the results of the study have changed the way I look at my chocolate protein powder.

Kelowna Gyms - One Life Fitness - Artificial sweeteners

Diet soda contains non-nutritive sweeteners that provide the desired sweet taste without the excess calories. I started drinking Tab cola over 30 years ago and over the years, as my knowledge of nutrition and physiology grew, gradually reversed my position from “its free” to thinking it’s probably the lesser of two evils. Aspartame and its potentially negative effects on the brain are fairly well known, but I never considered the possibility that sweetness without calories may alter the very structure of my brain.


Researchers at the University of San Diego recruited 24 young people from the San Diego area and split them into groups of non-diet soda drinkers and diet soda drinkers. The study was well prepared and accounted for sensitivities in taste, controlled for BMI and age. Participants were hooked up to fMRI scanning equipment at the University and were alternatively fed a sucrose solution, a saccharine solution and distilled water, while their brains were scanned. The results, according to the researchers were significant in the reward areas of the brain. The more diet sodas consumed regularly, the less the area responsible for signaling reward and controlling food intake responded. “….these results suggest that regular consumption of diet soda may be related to alterations in the reward experienced from both nutritive and non-nutritive sweet tastes.” Sweetness in the absence of calories confuses the reward centers in the brain and trains the brain to respond less to sweet flavors. Disrupting the normal prediction about calories and energy may make it more likely that the diet soda drinkers will over consume to receive a similar reward to non-drinkers.

I wonder how a really sweet protein shake with low calories and no fat or sugar affects the reward center of our brains. Does our brain expect a DQ blizzard in response to the thick, chocolaty sweetness that is my breakfast shake? Will I mindlessly over consume because my reward / satiety loops have been diminished by the trickery that is an artificial sweetener? Something to think about.


Green E. & Murphy C. (2012). Altered processing of sweet taste in the brain of diet soda drinkers, Physiology & Behavior, 107 (4) 560-567. DOI:10.1016/j.physbeh.2012.05.006

Source: |