By Bill DaleyIf sugary colas are as bad for you as nutritionists say and increasingly it stands to reason a drink containing a sugar substitute might be better for you, right? Not so fast! Studies of diet cola’s health impact are delivering mixed messages.While there are some folks who like the taste of diet colas — most folks pop for a diet beverage because it holds out the promise of lost weight. Some studies suggest it delivers on that; others disagree.“Diet colas have no calories,” said Marion Nestle, the New York University professor, author of What to Eat and expert in nutrition and public policy. “But on a population basis, they seem to have no impact on weight. Indeed, their use has increased in parallel with the rising prevalence of obesity.”She said the leading theory, as yet unproven, is “that the sweet taste fools the brain into thinking sweet calories are coming and reacts with hormonal and other metabolic signals accordingly. It’s easy to compensate for missing calories. But I don’t think anyone really knows what’s going on.”Meanwhile, other studies of diet cola claim consumption may increase your chances of having a stroke or developing metabolic syndrome, which can lead to cardiovascular disease. Tina Ruggiero, a registered dietician based in Tierra Verde, Florida, said that cardiovascular risk is particularly seen in men.“That doesn’t mean one diet cola a day will lead to a heart attack, but there’s some sort of connection,” she said.Somewhat more supportive of diet colas is Michael Jacobson, executive director of Centre for Science in the Public Interest. The Washington DC-based health advocacy group just released an animated short film targeting the health impacts of regular cola and sugary drinks called The Real Bears (realbears.org).“Diet soda is much better than regular soda. It lacks 10 teaspoons of sugar per 12oz,” he said, noting studies have shown people drinking regular cola have gained weight, while those consuming diet cola have not. “There’s good evidence diet soda doesn’t make you obese,” he said. “I think it’s better to drink diet soda (than regular), but diet soda does have its drawbacks.”There’s caffeine, he noted, which can affect some people. Phosphoric acids can promote tooth decay. There have been safety questions about the ingredients used in caramel colouring formulas and the artificial sweeteners used. The tug of war over the relative health merits of diet colas can bewilder consumers and cause tension in the scientific and food communities.Witness the recent kerfuffle over an article in the American Journal of Clinical Nutrition. The article outlined a scientific study of the health impacts of aspartame, an artificial sweetener used in diet colas. The study suggested the possibility of an increased risk of lymphoma and leukemia because of diet cola consumption. But researchers affiliated with the Harvard School of Public Health, Harvard Medical School and Brigham and Women’s Hospital in Boston couldn’t rule out chance as an explanation for their findings.According to National Public Radio (NPR), which reported on the study, the hospital’s public relations department issued a press release “exaggerating” the correlation between these cancers and the sweetener in diet cola. That was followed by the hospital pulling back on the press release, terming the study’s data as “weak.” And that touched off much speculation about why there was apparent backpedaling on the study.There will be continued research, no doubt, into diet colas. The question for right now is: Should you drink one next time you’re thirsty? The answer, nutritionists say, depends very much on your health, your diet and how much diet cola you drink.“People who drink an occasional cola won’t have a problem,” said Michelle Dudash, author of the new book ‘Clean Eating for Busy Families’.Two for you? It’s the folks who drink cola regularly, like two cans every day, who are more at risk for cola-related health issues, said Dudash, a registered dietician from Scottsdale, Arizona. Better to switch than fight? A move from regular cola to diet cola is generally seen healthwise as a good move, but not as good as forgoing cola.“One can of cola contains 140 calories, all from added sugar,” Dudash said. “For someone who has the habit of drinking a six-pack of regular cola per day, switching to diet cola is a step in the right direction, with the goal being to gradually taper that amount down.”Enjoy in moderation. Diet colas are not a health food but a recreational, fun food that’s OK to have once in a while, Dudash said. The trouble lies in people thinking that since diet colas have zero calories, they can have as much of it as they want. Not so. “It’s not nutritious at all,” she said. “It’s one of those in-moderation foods.”Define moderation? One diet cola every other day is “probably fine,” said Kristin Kirkpatrick, manager of wellness nutrition services at the Cleveland Clinic’s Wellness Institute in Ohio. More frequent consumption can foster a dependency for sweet flavours, she said.Ruggiero treats herself to one diet cola a week. “But I have a very good diet,” she quickly adds. “It’s a little treat when I want something fizzy or sweet. It’s not replacing more healthy items in my diet. I eat very well, I exercise, so I keep a little stash in my fridge.”Diet cola and kids? “No artificial sweetener has any place in a child’s diet, and that goes for diet cola too,” Dudash said. Better to serve water or a nutrient-rich beverage, she added.What is sweetening that drink? While the US government recognises a number of artificial sweeteners as safe for consumers, health organisations and advocacy groups have expressed differing views on them. They note some artificial sweeteners are still being studied, others need to be studied, and still more need to be restudied properly.The Center for Science in the Public Interest (CSPI) in the US posts a “Chemical Cuisine” page on its website (cspinet.org) rating the risk of various food additives, including artificial sweeteners. Sucralose is on the “safe” list. Aspartame is listed under CSPI’s “caution” column. On the “avoid” list are saccharin and acesulfame-potassium, which is sometimes used with sucralose in products.Read the labels. Jacobson said the best option is to look for a product sweetened entirely by sucralose, followed by a product using sucralose mixed with acesulfame-potassium. Still, when it comes to diet colas, Jacobson believes the fewer, the better. “The best diet drink would be water or water mixed with fruit juice, seltzer or seltzer mixed with fruit juice,” he said. — Chicago Tribune/MCT