The way we eat desperately needs to change. Experts estimate diet is a bigger contributor globally to early death than smoking.
The New York Times
Opinion
Dec 16, 2024 | 877 words | ★★★☆☆
It may come as a surprise, then, that an expert committee of scientists advising on the federal government’s dietary guidelines (the set of recommendations, released every five years, that shapes nutrition education and school lunches, among other things) recently declined to take a strong position against ultraprocessed foods. The experts felt that there wasn’t enough reliable science to draw accurate conclusions.
They were right about that. The problem is that the category of ultraprocessed foods, which makes up about 60 percent of the American diet by some estimates, is so broad that it borders on useless. It lumps store-bought whole-grain bread and hummus in with cookies, potato chips and soda. While many ultraprocessed foods are associated with poor health, others, like breakfast cereals and yogurt, aren’t.
Processing can also create products suitable for people with food intolerances or ones that have a lower environmental footprint. (Full disclosure: I have consulted for food companies that I feel make beneficial products, including Beyond Meat, which makes ultraprocessed meat alternatives that I believe are better for the planet.)
The most famous study on ultraprocessed foods was a randomized trial conducted by the National Institutes of Health, which compared an unprocessed diet, high in fresh fruits and vegetables, to a diet made up of ultraprocessed foods, but matched the amount of salt, sugar and fiber in the diets. The findings: People consumed about 500 calories more per day and gained more weight on the ultraprocessed diet. If it wasn’t the salt, sugar or fiber, what caused people to eat more?
It probably came down to energy density — how many calories are packed into each gram of food. In the N.I.H. study, the food in the ultraprocessed diet (not counting beverages) was overall almost twice as energy-dense as that in the unprocessed one. Studies have shown that we tend to overeat foods high in energy density. To understand why, think about how much fuller you might feel after eating three cups of broccoli (a low-energy-density food) compared with eating half a Hershey’s Bar (a high-energy-density food), even though in both cases you’d be consuming 100 calories.
Energy-dense foods tend to have less water and fiber and more fat compared with less energy-dense foods, like fruits and vegetables. Ultraprocessed foods are often very energy-dense because food companies have incentives to add fat or sugar to make foods tastier, and to remove water to make foods more shelf stable and cheaper to transport. Ultraprocessed foods also tend to come in forms that we consume more quickly. (Think about how little time it takes to gulp down a premade smoothie compared with eating a bowl of fruit.) And specific combinations of ingredients — carbohydrates combined with salt or sugar and fat — seem to lead us to overeat.
Of course, we should aim to consume a diet rich in unprocessed foods, such as oily fish, nuts, fruit and vegetables, as the expert committee advised in its report. And our modern food environment needs to change. But focusing on processing as a heuristic for the healthiness of foods risks throwing the baby out with the bath water. Take supermarket bread. Some well-to-do parents are baking their own bread to avoid the evils of industrial processing. But studies have not found a difference in health impact between industrially processed and homemade bread. And butter — churned from a single natural ingredient (milk) — is high in unhealthy saturated fat.
The focus on ultraprocessed foods has been a distraction from what we already know about nutrition, and we should have acted on it decades ago. We consume too much fast food, too many sugary beverages, too many cakes, doughnuts and chips. And we consume too few legumes, fruits and vegetables.
We need better food and nutrition policies that make it easier for people to purchase and consume a healthier diet. Pricing is one of the most effective ways to influence food purchasing and consumption habits. Soda taxes are a great example; these have led to reductions in sugar intake for children and adults, and emerging evidence suggests that children living in cities that tax soda are less likely to become obese. Such taxes could be extended to other high-sugar, high-calorie foods, like cookies and doughnuts, which have no nutritional benefits, and which we tend to overeat. Perhaps the revenue from this so-called doughnut tax could be used to subsidize the cost of fresh fruits and vegetables.
Mr. Kennedy and critics of ultraprocessed foods are right that our food landscape is very broken, and ambitious efforts that take on vested interests are needed to change it. The biggest dietary ills have been known for half a century; we need the new administration to finally act on them. ■
新英文外刊
每日精选优质外刊文章
扫码关注我们
