Diet soda is fine, and other food truths it's time you believed
I've been writing the "Unearthed" column, trying to find out what's really true about food, for some eight years now. In that time, I've dug into some questions that turned out to have surprising answers.
You can always gauge exactly how surprising by the number of people who call you an idiot on social media, and that's pretty much what happens when you try to put a stake through the heart of zombie ideas. What doesn't happen is that the ideas actually die.
I am shocked, shocked that I have persuaded basically nobody that these four things are true. But the fight continues.
1. We eat junk food because it's cheap.
If there is just one idea I would like to exile from food discourse, it's this one: We eat junk because of subsidies.
Junk food is cheap! That's because the building blocks of junk food — refined grains, sugar, oil — are cheap. But those building blocks are cheap because of the inherent qualities of the plant, not because the government has been subsidizing them for decades.
If you have any doubt about this, check out the estimates that agriculture schools publish of costs to produce an acre of corn versus an acre of broccoli.
According to an estimate from researchers in the University of California system, the cost to produce a 23-pound box of broccoli is about $15.
According to an Iowa State estimate, the cost to produce a 56-pound bushel of corn is about $4.
And the corn is way more food. That bushel makes 1,500 tortillas (6-inch tortillas, 60 calories), each with a quarter-cent's worth of corn. The box of broccoli makes 70 2-cup servings (roughly 150 grams, 60 calories), each with 21 cents' worth of broccoli. Yeah, we're not eating tortillas; we're eating Twinkies. The example is just to bring the inherent cheapness of the ingredients into perspective. I've talked to a lot of economists about this over the years, and most tell me that subsidies aren't responsible for more than about 10% of the price of commodity crops. And since food costs are typically 10% to 15% of the cost of processed food, that's 1% of the price of your Twinkie.
We eat Twinkie-esque foods because food companies with bazillion-dollar budgets and no concerns about our health stay up late trying to figure out how to make cheap food irresistible. And guess what? They've gotten very good at it.
2. Diet soda is totally fine.
There is zero evidence that diet soda is bad for us.
Oh, wait, except for those big observational studies. In those, diet soda correlates with everything bad. Cancer, obesity, diabetes, just for starters! But a funny thing happens when you actually feed people artificial sweeteners: nothing. Unless you count losing a little weight.
In the real world, drinking diet soda demonstrates that you don't listen to nutrition authorities, who have been recommending against it for decades. And if you're not listening about that, what else might you not be listening to? The cancer, obesity and diabetes that correlate with diet soda are most likely not caused by the diet soda, but by other eating and health habits for which diet soda is a marker.
If you're like most health-conscious people, the idea that artificial sweeteners are bad is deeply ingrained. But the most important thing to remember about them is that you consume them in tiny quantities. A Splenda packet contains 12 milligrams of sucralose. Of course, it's possible for 12 milligrams of something to do you harm, but if something's that dangerous, it's pretty easy to figure it out.
People have been trying to find problems with artificial sweeteners for decades, and they just haven't. If you drink them in soda, or use them to sweeten things you make at home, keep on keeping on. It's just fine.
3. Local foods aren't better for the climate.
I go out of my way to buy local veg and meat. I want agriculture in my community. I like going to the farmers market.
But any way you slice it, local foods aren't better for the environment. They're just not.
Intuitively, it makes sense that they should be! If your lettuce travels crosstown instead of cross-country, that's a couple thousand fossil-fueled miles that don't have to happen. But it turns out that transport is a very small fraction of the climate impact of food: less than 10%, most of the time.
Climate isn't the only thing I think about when I choose dinner. Local farms can contribute to local economies, provide community touchstones and just be a place where a kid can meet a pig. If you want to cut the climate harm of your diet, eat more of the crops that have the smallest environmental impact: grains, legumes, nuts, tubers, tree fruits. It doesn't mean you have to stop buying local.
4. Salad is a first-world luxury.
Let's get one thing straight. Lettuce is a vehicle to bring refrigerated water from farm to table.
If you have an intuitive sense that a food that's 96% water is a waste of resources and a nutritional zero, you're right. If you don't, you could be one of the bazillion people who came down hard on me when I wrote about the leafy green climate menace that is salad.
Okay, that's a little unfair. Salad isn't a menace; it's just a luxury. It uses too many resources for too little food to be a smart choice for either human or planetary health. It graces my table because I like it and because it can help me say no to seconds of lasagna. But that's a solution to a first-world problem: too much food. The idea that we're deliberately growing and eating food specifically because it's low-calorie makes sense only in a world of overabundance.
But there's a hitch there, too. Lettuce lends its health halo to anything that gets put in a bowl with it, and the salads we think of as healthful generally aren't. If you buy a salad, and then remove the lettuce, you see what you're really eating for lunch: sad little brown piles of croutons, dressing, shredded cheese, and chicken strips.
Of course there are grain- or bean-rich salads, populated with bona fide nutritious vegetables like kale and broccoli, that are genuinely nutritious and a fine choice. But they're the outliers. Most salads are nutritional and environmental losers.
Tamar Haspel is the author of "To Boldly Grow: Finding Joy, Adventure, and Dinner in Your Own Backyard." An oyster farmer on Cape Cod, she writes Unearthed, a monthly commentary in pursuit of a more constructive conversation on divisive food-policy issues.