Diet Soda for Weight Loss? Think Again!

Aspartame is one of the most popular low-calorie sweeteners found in diet sodas, teas, energy drinks, coffee flavorings, protein shakes, flavored milk, juices and other flavored beverages. Since aspartame is two hundred times sweeter than sugar, you only need a very small quantity of aspartame to create a sweet-tasting product with few or even no calories.

Sugar and other caloric sweeteners such as high fructose corn syrup have been blamed for obesity epidemic. So people naturally lean towards artificial sweeteners when they have sugar cravings but want to loose weight. A lot of shakes or weight loss bars that are promoted for dieting will have aspartame included to ensure that they meet specific calorie goals. Consuming excessive amounts of artificial sweeteners like aspartame can have negative health effects over time.

Do Artificial Sweeteners Actually Help Reduce Weight?

Surprisingly, several studies linked artificial sweetener use to weight gain, not weight loss!!

For example, The San Antonio Heart Study examined 3,682 adults over a seven- to eight-year period in the 1980s. When matched for initial body mass index (BMI), gender, ethnicity, and diet, drinkers of artificially sweetened beverages consistently had higher BMIs at the follow-up, with dose dependence on the amount of consumption. Average BMI gain was +1.01 kg/m² for control and 1.78 kg/m² for people in the third quartile for artificially sweetened beverage consumption.

The American Cancer Society study conducted in early 1980s included 78,694 women. At one-year follow-up, 2.7 percent to 7.1 percent more regular artificial sweetener users gained weight compared to non-users. The difference in the amount gained between the two groups was less than two pounds, albeit statistically significant. Saccharin use was also associated with eight-year weight gain in 31,940 women from the Nurses’ Health Study conducted in the 1970s.

 

Intestinal Enzyme May Be the Problem

In a study published in Applied Physiology, Nutrition and Metabolism, the researchers found a possible mechanism explaining why use of the sugar substitute aspartame might not promote weight loss.

The study showed that the aspartame breakdown product phenylalanine interferes with the action of an enzyme previously shown to prevent metabolic syndrome – a group of symptoms associated with type 2 diabetes and cardiovascular disease. They also showed that mice receiving aspartame in their drinking water gained more weight and developed other symptoms of metabolic syndrome than animals fed similar diets lacking aspartame.

“Sugar substitutes like aspartame are designed to promote weight loss and decrease the incidence of metabolic syndrome, but a number of clinical and epidemiologic studies have suggested that these products don’t work very well and may actually make things worse,” says Richard Hodin, MD, the study’s senior author. “We found that aspartame blocks a gut enzyme called intestinal alkaline phosphatase (IAP) that we previously showed can prevent obesity, diabetes and metabolic syndrome; so we think that aspartame might not work because, even as it is substituting for sugar, it blocks the beneficial aspects of IAP.”

In a series of experiments the team first found that the activity of IAP was reduced when the enzyme was added to a solution containing an aspartame-sweetened soft drink but remained unchanged if added to a solution with a sugar-sweetened beverage.

IAP is primarily produced in the small intestine, and the researchers found that injecting an aspartame solution into segments of the small intestines of mice significantly reduced the enzyme’s activity.  In contrast, IAP activity remained unchanged in bowel segments injected with a saline solution.

To better represent the effects of consuming beverages or other products containing aspartame, the researchers followed four groups of mice for 18 weeks. Two groups were fed a normal diet, one receiving drinking water with aspartame, the other receiving plain water. The other two groups were fed a high-fat diet, along with either aspartame-infused or plain water. Animals in the normal diet group that received aspartame consumed an amount equivalent to an adult human’s drinking about three and a half cans of diet soda daily, and aspartame-receiving animals in the high-fat group consumed the equivalent of almost two cans.

At the end of the study period, while there was little difference between the weights of the two groups fed a normal diet, mice on a high-fat diet that received aspartame gained more weight than did those on the same diet that received plain water. Aspartame-receiving mice in both diet groups had higher blood sugar levels than did those fed the same diets without aspartame, which indicates glucose intolerance, and both aspartame-receiving groups had higher levels of the inflammatory protein TNF-alpha in their blood, which suggests the kind of systemic inflammation associated with metabolic syndrome.

“People do not really understand why these artificial sweeteners don’t work. There has been some evidence that they actually can make you more hungry and may be associated with increased calorie consumption. Our findings regarding aspartame’s inhibition of IAP may help explain why the use of aspartame is counterproductive,” says Hodin, who is a professor of Surgery at Harvard Medical School. “While we can’t rule out other contributing mechanisms, our experiments clearly show that aspartame blocks IAP activity, independent of other effects.”

So before you open that can of diet soda, think again. Plain water is probably your best bet for hydration.

 

Source:

1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2892765/
2. http://www.massgeneral.org/about/pressrelease.aspx?id=2016. Note: Content may be edited for style and length.