The (Not So) Skinny on Diet Sodas

I admit it. I love Coke Zero. The carbonation, the taste (close to regular Coke!), even the sound as it’s poured over ice all make for a refreshing drink. The best part? As its name implies, ZERO calories! Zero calories equal zero consequences, right? Heck no! Diet sodas have long been thought to contribute to weight gain and now there is scientific evidence to support this theory. But how exactly can diet sodas make us fat? Two studies presented last year in San Diego at the American Diabetes Association meeting shed some light on this.

In the first study, researchers at the Texas Health Science Center at San Antonio collected height, weight, waist circumference and diet soda intake data every 3.6 years from 474 people aged 65-74. The waists of those who drank diet soft drinks grew 70 percent more than those who did not drink it. Incredibly, people who drank two or more diet sodas a day had waist-circumference increases that were five times larger than non-diet-soda drinkers. This indicates a link between Diet Sodas and weight gain.

In a related study, researchers looked at the relationship between aspartame, the artificial sweetener found in diet sodas, and fasting glucose and insulin levels. Forty mice were fed a high fat diet for 3 months; the experimental group diet included aspartame, the control group diet did not. At the end of the study, mice fed the aspartame diet had higher blood glucose levels than the control group. This suggests that artificial sweeteners can indeed raise blood sugar levels. Even worse, previous rodent studies have stated that artificial sweeteners stimulate insulin secretion, alter the pH in the gut (killing beneficial bacteria), and cause the brain to think your body is hungry.

What does all of this mean? If the studies are correct, a few things are going on. First, artificial sweeteners fool your taste buds and your brain, telling them that sugar is coming in. Without a real food source however, your brain tells you to keep eating until you get those calories. The artificial sweeteners then cause blood sugar to rise and stimulate the release of insulin, which tells the body to store fat.
The anecdotal evidence is overwhelming. People I know who drink lots of diet soda, just like the people who eat loads of Lean Cuisines, are typically overweight. Most doctors agree that diet sodas are not only linked to weight gain, but diabetes, kidney damage and cardiovascular problems. Time and time again we have seen that artificial food products (like aspartame, which is made from genetically modified organisms) have deleterious effects on people. If it is zero calories and is not water, coffee or tea, it’s likely poison.

*Journal article: “A Role for Sweet Taste: Calorie Predictive Relations in Energy Regulation by Rats,” Susan E. Swithers, PhD and Terry L. Davidson, PhD, Purdue University; Behavioral Neuroscience, Vol. 122, No. 1.