Updated May 29, 2015
By Nour Zibdeh, MS, RD, CLT
Soda may be your drink of choice at the movie theater, or perhaps it’s your middle-of-the-day caffeine boost with lunch. But that same sweet, flavorful liquid that tickles your taste buds wreaks havoc on your health. Every time you reach for a soda, you’re putting yourself at risk for a fuller waist, weaker bones and several other health problems — including heart disease. Here are seven reasons to stop mid-sip, and put down the soda for good.
Soda drinkers are more likely to gain weight and become obese than those who prefer other beverages to quench their thirst. No surprise there: a 12-oz can of pop packs between 140 and 180 calories, and it’s easy to chug down a 16- or 20-ounce bottle a day. Calories from soda are essentially “empty calories” — that is, they come from added sugars (in the case of soda) or solid fats and have no nutritional value. They won't add anything healthy to your diet and won’t satisfy your hunger.
But did you know that reaching for diet soda instead may be as bad for your waistline? A recent study of nearly 800 adults found that drinking more diet beverages (including low- or no-calorie soda) was associated with a higher waist circumference and overall body mass index, or BMI (a measure that indicates overweight and obesity). Although an association doesn't mean that diet soda causes a larger waistline, the connection is important: Just because you're drinking a no-calorie drink doesn't mean you're drinking a healthy beverage! Still not sure if diet soda is a no-no? Consider this: The artificial sweeteners that make a no-cal drink palatable may actually be linked to weight gain. A 2008 study of more than 5,000 adults found a link between drinking artificially sweetened beverages (like zero-calorie colas and energy drinks) and putting on the pounds. The weight gain wasn't just a short-term thing, either: The study's subjects were followed for up to 8 years, indicating a possible connection between artificial sweeteners and long-term weight gain.
Weight gain and belly fat increase your chances of developing a disease that's all too common in the US: type 2 diabetes. Being overweight or obese is one of the biggest risk factors for this condition. Moreover, the way the excess fat is distributed on your body plays a role: If most of the extra pounds are found around your abdomen, your risk of developing type 2 is higher. A 2010 review examined 11 studies that looked at the link between sugar-sweetened beverages and type 2 diabetes as well as metabolic syndrome. This meta-analysis found that people who drank the most sugary drinks per day were at a higher risk of developing both type 2 diabetes and metabolic syndrome. What's metabolic syndrome? In short, it's a group of risk factors that increase your risk of heart disease, diabetes, stroke and other health problems.
In a study that followed more than 42,000 men for 22 years, frequent regular soda consumers had elevated levels of triglycerides, C-reactive protein and other inflammatory factors, and lower levels of heart-protective, "good" cholesterol — all signs that soda may hurt heart health. Notably, soda drinkers were much more likely to suffer a heart attack over the course of the study; each soda that participants drank on a daily basis increased their chances of heart attack by 19%, even after other variables, like diet quality and BMI, were taken into account. These results were limited to people who consumed sodas sweetened with sugar; diet soda drinkers did not have increased chances of cardiovascular disease.
The link between added sugars and cardiovascular disease is serious enough that the American Heart Association suggested limiting intake of added sugars to 100 calories a day for women and 150 calories a day for men. Just one regular 12-ounce soda would push you over that daily limit.
Want to build strong bones? Put down your soda. Colas, like Coke or Pepsi, contain phosphoric acid to give the drink a tangy flavor and to prevent mold and bacteria from growing. However, phosphoric acid has been shown to interfere with calcium absorption, which is needed for strong bones. The Framingham Osteoporosis Study found that women who drank regular, diet or even decaffeinated cola had bone mineral density almost 4% lower than that of women who weren’t soda drinkers. The effect was only observed in soda types that contained phosphoric acid, like cola drinks, but not in clear carbonated sodas. Even though clear sodas didn't affect bone mineral density, such drinks still pose a risk to bone health when they replace bone-building milk in children's and adolescent's diets.
Phosphoric acid does more than weaken bones: Phosphoric-containing beverages change the way kidneys process urine and can increase your risk of developing kidney stones. After comparing the diets of more than 400 chronic kidney disease patients to the diets of a similar number of healthy individuals, researchers concluded that drinking two or more colas a day was associated with approximately two times the risk for chronic kidney disease. Both regular and diet colas had this disease-promoting effect; non-cola carbonated drinks were not linked to an increased risk for disease.
Both regular and diet soda are acidic and can erode the protective layer of enamel that coats healthy teeth, leaving your teeth more sensitive and susceptible to decay. Additionally, when you drink regular soda, you bathe your teeth in sugar. This feeds bacteria that live on your teeth, which secrete even more enamel-eating acid as they digest the sugar.
And don’t fall for commercials urging you to reach for a can of pop to quench your thirst. When you're thirsty, you have less saliva, which normally protects tooth enamel by neutralizing the acidity from carbonated beverages and bacteria. As a result, chugging soda when you're thirsty bombards your teeth with acid and sugar while its defenses are down.
If the harmful ingredients in soda aren’t enough to make you think twice about your beverage choice, consider this: The soda cans themselves contain a chemical you should probably avoid. Nearly all soda cans are lined with bisphenol A, or BPA, to prevent contamination and extend shelf life. This chemical mimics the hormone estrogen; some studies in animals indicate that developing fetuses, infants and children may be especially vulnerable to its potential effects. Additional animal studies suggest that BPA may be linked to a variety of health issues, ranging from heart disease to infertility. Although the current perspective of the US Food and Drug Administration is that BPA is safe as a “food contact” substance, there's a slowly growing body of evidence examining the link between BPA and various health issues. When assessing sources of BPA in the American diet, soda is a major one. The easiest way to reduce BPA exposure may be to shake your soft drink habit.
Published October 15, 2012.
Nour Zibdeh is a registered dietitian and nutrition coach specializing in weight management, cardiovascular disease, food sensitivities, and digestive health. She coaches individuals by merging nutrition science, intuitive and mindful eating, and healthy cooking in her counseling approach. Nour shares recipes and nutrition tips at www.nourition.com/blog.