We know sugar is bad for us and it is often the first thing we try to restrict when we become health conscious.
Those with a strong sweet tooth often turn to diet soda as a healthy alternative. There’s no sugar in it, and it has no calories.
It is not uncommon to see someone order a BigMac, large fries and a diet soda. If I had banged my head against the wall every time I saw that happening, I’d probably be dead.
They probably believe they are losing weight by replacing sugary soda with a calorie free version.
Well, not exactly.
In this article I will answer the question “is diet soda bad for you” and find out whether it causes weight loss, weight gain, or neither.
What exactly is diet soda?
There are many different types. There is Diet Coke, Coke Light, Pepsi Max, Sprite Zero, and hundreds of other kinds.
Unsurprisingly, as people are getting fatter and fatter, these calorie free beverages have become very popular.
What most of them have in common is carbonated water with some artificial sweeteners, colorants and other additives.
Common sweeteners include Aspartame, Phenylalanine, Sucralose, Cyclamates, Saccharin and Acesulfame Potassium (1).
I am not going to talk about individual sweeteners in this article, but take a look at what happens to people when they drink diet soda.
Is diet soda bad for you?
To give you a short answer, then according to the epidemiological studies, diet soda is bad for you. It may even be worse than regular, sugared soda.
Why? I don’t know.
Maybe the sweetness itself affects the brain in some way, making it want to eat more.
Maybe people tend to consume unhealthy food with their diet sodas, possibly because they think they can compensate for the calories they’re “saving” by not drinking regular soda.
Whatever the actual mechanism, there is a clear association between diet soda consumption and several serious diseases.
Diet Soda, Metabolic Syndrome and type II diabetes
Are you familiar with the metabolic syndrome?
It is a collection of symptoms such as insulin resistance, elevated triglycerides in the blood, reduced HDL cholesterol, raised blood pressure, fat accumulation around the midsection, and some others. Basically what happens to genetically susceptible people when they consume a western diet.
It turns out that diet soda may increase the risk of metabolic syndrome.
In one study, published in 2008, they followed 9514 individuals for 9 years. Those who drank the most diet soda had 34% greater chances of developing the metabolic syndrome. Regular soda had no effect (2).
Another study followed 6814 middle-aged and elderly adults for several years and discovered that daily diet soda consumption increased risk of metabolic syndrome by 36% and type II diabetes by a whopping 67% (3).
Diet Soda and Cardiovascular Disease
A study of 2564 Manhattan residents found that those who drank diet soda every day had a 61% higher risk of stroke and heart attack. Regular soda did not increase the risk (4).
Diet Soda and Preterm delivery
In Denmark, a study of 59 thousand women discovered that 1 serving of diet soda per day increased risk of preterm delivery by 38%, while 4 servings per day increased the risk by 78%. Regular soda did not increase risk of preterm delivery (5).
Diet soda and weight gain
Let’s disregard those diseases for a while and focus specifically on diet soda and weight gain.
The main reason people drink diet soda is that it lacks calories and should therefore help to lose weight. According to the studies, the exact opposite happens.
A study performed at the University of Texas discovered that consumers of diet soft drinks were 65% more likely to become overweight and 41% more likely to become obese, during a seven to eight year period. Regular soft drinks did not have any significant effect (6).
Another study of over 80 thousand women discovered that consuming artificial sweeteners contributes to weight gain (7).
Even though the above studies aren’t randomized clinical trials, the association between diet soda consumption and disease is statistically significant.
I must admit that I was incredibly surprised when doing research on this matter.
I already suspected that diet soda wouldn’t be much better than regular (sugary) soda, but I had no idea that it would actually be worse (according to the epidemiological studies).
Diseases like metabolic syndrome, obesity, type II diabetes and cardiovascular disease kill millions of people each year and anything that may potentially contribute to those diseases should obviously be avoided.
[Update 26/5/2012]: As some readers have correctly pointed out, the studies above only show that there is a correlation between diet soda and disease. These are not controlled trials and do not prove that diet soda caused the diseases. I apologize for any misunderstanding.