The decline of Diet Coke is a good thing: Elaine Chin

Fat free? Not really.

(Photo:  niallkennedy/Flickr)

(Photo: niallkennedy/Flickr)

Amid falling sales, Coca-Cola has launched new ads defending the use of artificial sweeteners in its diet product. The beverage giant wants consumers to believe there’s nothing wrong with people consuming food chemical alternatives. I disagree.

Ever since artificial sweeteners like Aspartame (Coke’s sweetener of choice) hit the marketplace in the 1970s, there have been health concerns. Studies have linked high doses of sweeteners to cancer in rats, though similar findings have not been shown in humans. That hasn’t prevented people like Michael Jacobson, executive director for the U.S. Center for Science in the Public Interest, from saying no one should eat or drink products that contain the sweetener. “Aspartame has been found to cause cancer—leukemia, lymphoma, and other tumours—in laboratory animals, and it shouldn’t be in the food supply,” he says in a statement issued on the Center’s web site.

Coca-Cola has a pressing business need to defend sweeteners. Diet soda sales are falling faster than for sugar-sweetened soft drinks, according to Beverage Digest. Last year, sales for Diet Coke fell 3%, compared to 1% for Coke. Diet Pepsi sales were off sharply at 6.2%, while Pepsi saw a 3.4% slide. While declining sales may be bad for soft drink companies, they’re good for a public health system straining under an obesity epidemic posing as much or more of a threat than cancer.

Sweeteners fan that epidemic. In fact, I would liken the potential effects of sweetener on obesity to that of adding oil to a forest fire.

How sugar substitutes work in your body

In July 2013, research by Susan E. Swithers, a Purdue professor of psychological sciences and a behavioural neuroscientist, warned that diet beverages may not be a healthy way to manage weight. Swithers reviewed and evaluated the most recent research on whether the consumption of high-intensity sweeteners, despite having zero or low calories, may result in overeating, weight gain or other health problems. Her research included studies on diet soft drinks that contained aspartame, sucralose and saccharin (about 30% of American adults regularly consume these sweeteners.).

Her conclusions suggest diet soda may be just as bad as non-diet soda. As well as contributing to weight gain, she’s concerned about a possible connection to heart disease, stroke, diabetes, metabolic syndrome and high blood pressure. And diet sodas aren’t the only places that artificial sweeteners creep into our diets. Some yogurts and baked goods incorporate the no-cal sweet stuff, too.

Earlier studies support Swithers’ claims. The San Antonio Heart Study reported an increase in body weight gain for adults and adolescents who consumed artificially sweetened beverages vs. beverages regularly sweetened. Data from a number of other studies, including the Nurses’ Health Study and the Health Professionals Follow-up Study also report greater risk of type 2 diabetes, high blood pressure, heart disease and metabolic syndrome, which is related to diabetes and cardiovascular problems, for consumers of artificially sweetened beverages. Some data indicated that those who consumed artificially sweetened beverages had double the risk of metabolic syndrome (a precursor to diabetes) compared to non-consumers.

So what is going on here? How can diet soda be bad?

Some studies show that when people drink diet soda, they engage in what’s known as “cognitive distortion,” deciding that since they saved on liquid calories they can splurge elsewhere—the “diet coke and fries” order.

Even studies on animals note a link between consuming artificial sweeteners and overeating that leads to weight gain. It may be that artificial sweeteners throw off the body’s ability to know how many calories it needs. Normally when someone consumes something sweet, the body expects calories and sugar to follow. But when a person drinks diet soda the payoff never arrives. Your body gets confused and this can lead to overeating. In the animal models, that can lead to an increase in blood sugar spikes which can lead to diabetes. Perhaps this is also happening in humans, too.

Not only do I worry about what harm artificial sweeteners may be doing to us and our cells, but  I’m even more concerned about what they’re doing to our hormones. Overeating leads to an increased insulin response. Insulin then stores our unused carbohydrates as fat.

So the next time you go to order a diet soda to manage your weight, try a Perrier or San Pellegrino instead. They’re fizzy with no calories or sweeteners, and they’re safe to consume. You’ll discover it pays to think twice about thirst quenchers. Like the Diet Coke slogan once said, “You are what you drink.”

Dr. Elaine Chin is the Chief Medical Officer of the Executive Health Centre. Her clinic was the first in North America to offer genetics testing and now tests telomere length as well.