Eating Fast Is Bad for You—Right?
Where my vacuuming mouth goes, advice to constrain it follows. Internet writers have declared slowness akin to slimness; self-described “foodies” lament that there’s “nothing worse” than watching a guest inhale a painstakingly prepared meal. There are even children’s songs that warn against the perils of eating too fast. My family and friends—most of whom have long since learned to avoid “splitting” entrees with me—often comment on my speed. “Slow down,” one of my aunts fretted at a recent meal. “Don’t you know that eating fast is bad for you?”
I do, or at least I have heard. Over the decades, a multitude of studies have found that people who eat faster are more likely to consume more calories and carry more weight; they’re also more likely to have high blood pressure and diabetes. “The data are very robust,” says Kathleen Melanson of the University of Rhode Island; the evidence holds up when researchers look across geographies, genders, and age. The findings have even prompted researchers to conduct eating-speed interventions, and design devices—vibrating forks and wearable tech—that they hope will slow diners down.
But the widespread mantra of go slower probably isn’t as definitive or universal as it at first seems. Fast eaters like me aren’t necessarily doomed to metabolic misfortune; many of us can probably safely and happily keep hoovering our meals. Most studies examining eating speed rely on population-level observations taken at single points in time, rather than extended clinical trials that track people assigned to eat fast or slow; they can speak to associations between pace and certain aspects of health, but not to cause and effect. And not all of them actually agree on whether protracted eating boosts satisfaction or leads people to eat less. Even among experts, “there is no consensus about the benefits of eating slow,” says Tany E. Garcidueñas-Fimbres, a nutrition researcher at Universitat Rovira i Virgili, in Spain, who has studied eating rates.
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The idea that eating too fast could raise certain health risks absolutely does make sense. The key, experts told me, is the potential mismatch between the rate at which we consume nutrients and the rate at which we perceive and process them. Our brain doesn’t register fullness until it’s received a series of cues from the digestive tract: chewing in the mouth, swallowing down the throat; distension in the stomach, transit into the small intestine. Flood the gastrointestinal tract with a ton of food at once, and those signals might struggle to keep pace—making it easier to wolf down more food than the gut is asking for. Fast eating may also inundate the blood with sugar, risking insulin resistance—a common precursor to diabetes, says Michio Shimabukuro, a metabolism researcher at Fukushima Medical University, in Japan.
The big asterisk here is that a lot of these ideas are still theoretical, says Janine Higgins, a pediatric endocrinologist at the University of Colorado Anschutz Medical Campus, who’s studied eating pace. Research that merely demonstrates an association between fast eating and higher food intake cannot prove which observation led to the other, if there’s a causal link at all. Some other factor—stress, an underlying medical condition, even diet composition—could be driving both. “The good science is just completely lacking,” says Susan Roberts, a nutrition researcher at Tufts University.
Scientists don’t even have universal definitions of what “slow” or “fast” eating is, or how to measure it. Studies over the years have used total meal time, chew speed, and other metrics—but all have their drawbacks. Articles sometimes point to a cutoff of 20 minutes per meal, claiming that’s how long the body takes to feel full. But Matthew Hayes, a nutritional neuroscientist at the University of Pennsylvania, criticized that as an oversimplification: Satisfaction signals start trickling into the brain almost immediately when we eat, and fullness thresholds vary among people and circumstances. Studies that ask volunteers to rate their own speeds have issues too: People often compare themselves with friends and family, who won’t represent the population at large. Eating rate can also fluctuate over a lifetime or even a day, depending on hunger, stress, time constraints, the pace of present company, even the tempo of background music.
In an evolutionary sense, all of us humans eat absurdly fast. We eat “orders of magnitude quicker” than our primate relatives, just over one hour a day compared with their almost 12, says Adam van Casteren, a feeding ecologist at the University of Manchester, in England. That’s thanks largely to how we treat our food: Fire, tools such as knives, and, more recently, chemical processing have softened nature’s raw ingredients, liberating us from “the prison of mastication,” as van Casteren puts it. Modern Western diets have taken that pattern to an extreme. They’re chock-full of ultra-processed foods, so soft and sugar- and fat-laden that they can be gulped down with nary a chew—which could be one of the factors that drive faster eating and chronic metabolic ills.
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In plenty of circumstances, slowing down will come with perks, not least because it could curb the risk of choking or excess gas. It could also temper blood-sugar spikes in people with diets heavy in processed foods—which whiz through the digestive tract, Roberts told me, though the healthier move would probably be eating fewer of those foods to begin with. And some studies focused on people with high BMI, including Melanson’s, have shown that eating slower can aid weight loss. But, she cautioned, those results won’t necessarily apply to everyone.
The main impact of leisurely eating may not even be about chewing rates or bite size per se, but about helping people eat more mindfully. “A lot of us are distracted when we eat,” says Fatima Cody Stanford, an obesity-medicine physician at Massachusetts General Hospital. “And so we are missing our hunger and satiety cues.” In countries such as the United States, people also have to wrestle with the immense pressure “to be done with lunch really fast,” Herman Pontzer, an anthropologist at Duke University, told me. Couple that with the fast foods we tend to reach for, and maybe it’s no shock that people don’t feel satisfied as they scarf down their meals.
The point here isn’t to demonize slow eating; in the grand scheme of things, it seems a pretty healthful thing to do. At the same time, that doesn’t mean that “eat slow” should be a blanket command. For people already eating a lot of high-fiber foods—which the body naturally processes ploddingly—Roberts doesn’t think sluggish chewing has much to add. The extolling of slow eating is, at best, “a half truth,” Hayes told me, that’s become easy to exploit.
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I do feel self-conscious when I’m the first person at the table to finish by a mile, and I don’t enjoy the stares and the comments about my “big appetite.” Certain super-slow eaters might get teased for making others wait, but they’re generally not getting chastised for ruining their health. When I asked experts if it was harmful to eat too slowly, several of them told me they’d never even considered it—and that the answer was probably no.
Still, for the most part, I’m happy to be the Usain Bolt of chewing. My hot foods stay hot, and my cold foods stay cold. I’ve intermittently tried slow eating over the years, deploying some of the usual tricks: smaller utensils, tinier bites, crunchier foods. I even, once, tried to count my chews. The biggest difference I felt, though, wasn’t fullness or more satisfaction; I just kind of hated the way that my mushy food lingered in my mouth.
Maybe if I’d stuck with slow eating, I would have lost some gassiness, choking risk, or weight—but also, I think, some joy. There’s something to speed-eating that can be plain old fun, akin to the rush of zooming down an empty highway in a red sports car. If I have just an hour-ish (or, knowing me, less) of eating each day, I’d prefer to relish every brisk, indecorous bite.