Diet Soda, Weight Gain and Digestive Problems

Think drinking diet soda will help you stave off extra pounds?  Think again.  Research actually shows (in numerous studies) that the artificial sweetener primarily used in diet drinks, aspartame, may actually cause obesity.  According to a recent study done at Purdue University, “…people who drink more diet drinks are at higher risk for obesity and metabolic syndrome, a collection of medical problems such as abdominal fat, high blood pressure and insulin resistance that put people at risk for heart disease and diabetes.” [1]

The reasoning for obesity, metabolic syndrome and weight gain makes perfect sense.  Artificial sweeteners, though lacking calories, still have a sweet taste that most would argue is even sweeter than table sugar.  When the artificial sweetener is consumed, it triggers the body to release insulin because the body does not know the difference between sugar and aspartame.

When we eat, insulin is always released as a way to keep blood glucose levels stable.  If you drink a diet soda, there is no sugar, but insulin is still released.  If insulin is circulating in the blood without sugar in the blood, it will trigger the response to eat as a means to keep blood glucose levels in balance with insulin levels (a hypoglycemic effect).  Therefore, drinking diet soda will actually make you hungrier causing you to consume more calories.

In a study published by The Nurse Practitioner in 2008, artificial sweeteners can cause GI tract problems ranging from diarrhea to the most commonly noted condition, irritable bowel syndrome (IBS). [2]  IBS is characterized by cramping, abdominal pain, bloating, constipation, diarrhea, and discomfort.  IBS is not permanent, and can be corrected through proper diet.

Although diet soda, or it’s component aspartame, may cause weight gain, insulin resistance and IBS, there is a bright side.  You may become well-preserved, much like the cow eye you dissected in high school biology class.  The stinky, preservation liquid that you used to smell coming from the biology lab in school, a.k.a. formaldehyde, is one of the products formed when aspartame is broken down in the body.  While one study shows there is no harm to humans having formaldehyde accumulate in the body, I am not so sure I really agree. [3]  More studies need to be done to show it’s effects on cell health.

And finally, diet soda, like most diet foods, typically encourage over-consumption.  When people think they are “saving” calories by drinking diet soda, they typically eat more food thinking they have the extra room for calories.

Diet sodas, like all foods, are OK in moderation.  But keep these types of foods to the special occasion and not the everyday occurrence.


[1] “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.

[2]  “Artificial sweetener linked to GI problems.(Literature Review: Gastrointestinal Care)(Report).” The Nurse Practitioner 33.6 (June 2008): 47(2).

[3] Oyama, Y., H.
Sakai, T. Arata, Y. Okano, N. Akaike, K. Sakai, and K. Noda. ”Cytotoxic
effects of methanol, formaldehyde, and formate on dissociated rat
thymocytes: A possibility of aspartame toxicity.(Author abstract).” Cell Biology and Toxicology 18.1 (Jan 2002): 43(8)

About Kimberly Dawson, M.S.

Leave a Reply