In Louisiana there is a supermarket chain called Winn-Dixie. They sell their own soda brand called ‘Chek’, which lines the shelves with bright, colorful, retro-style labels. Thinking about it makes me thirsty.
On most days Chek sells for about half the price of standard Coca-Cola products, so when it goes on sale I lean in. Hard. This week I brought home a sample (read: 12-pack) of the diet strawberry, grape, and orange flavors. Highly recommend them all, though lemon-lime is still champ.
Predictably, opening the beverage drawer in my fridge has led many a guest to catch their breath. There’s usually a pause, followed by a careful attempt at mitigation. “Wow. Um, your kids must really like soda, huh?”
There’s generational irony in this. When I was young I marveled at the constant supply of Tab in the fridge. For my mother, this pink-canned diet cola (the country’s first) was a needful thing. What an addict, I thought. Now, opening my refrigerator is a time warp.
Health studies exploring the effects of diet soda are legion, and a constant source of clickbait. Google it and you’ll always find a recent, highly trafficked news story reporting on a recent, highly trafficked diet soda study.
This is not new. With my mother’s Tab the big scare was saccharin, and the possibility—nay, near certainty—it causes bladder cancer. Based on rat studies, reports in the 1970s declared saccharin a carcinogen. But a close look shows the risk was often for second generation rats (babies of saccharin-devouring rat-mommies) and doses were a human equivalent of about 1,500 soda cans per day.
That’s a lot of Chek, even for me. And alas, despite an explosion of saccharin use in the 1970s and ‘80s, there never was a bump in bladder cancer. In fact it’s going down.
Today, however, headlines on diet soda claim it can cause diabetes, obesity, heart disease, and giant eyeballs (maybe not the last one). But also. . . DEATH. A commonly cited 2019 study from Europe, for instance, reports a 26% higher mortality among regular diet soda consumers.
Which helps clarify why diet soda is totally safe. A “26% higher risk of death” means a relative risk of 1.26 among diet soda drinkers. To use a favorite comparison, the relative risk of lung cancer for smokers is about 30, just a tad higher than 1.26. And the higher risk of death isn’t 26%, it’s 3,000%.
That is what a causal relationship looks like. Diet soda studies are actually proof of its safety. And, of course, even if they did find meaningful numbers, the studies are hopelessly confounded by the baseline differences between people who do, and don’t, drink diet soda. Comparing their outcomes and blaming the soda is like blaming overalls versus suits for the health differences between farmers and financiers. Dumb.
Finally, I must reiterate Newman’s Law: Studies finding no association are far more predictive, and more likely correct, than studies finding an association. In fact if ANY studies find no relationship, it’s likely there is none. And there lots of studies showing no relationship between diet soda and poor health outcomes. The Law is both mathematically and intuitively obvious. The absence of a statistical finding means either there is no important relationship, or else the confounders on both positive and negative sides of the equation have perfectly balanced each other. Highly improbable.
The lack of association between diet soda and health problems found in many large studies, plus a piddly relative risk of 1.26, basically clears diet soda of wrongdoing. And I’m certainly not the first to say so: Aaron Carroll, who IMHO is pretty much always right about study interpretation, has written on this topic multiple times.
All of which means the dangers of diet soda are, as a famously bad dancer once said, “Fake, fake, fake, fake.” And so is the strawberry flavor. Slurp.
