For years I assumed there were only two ways to make a French fry less greasy, and both of them made the fry worse. Use less oil. Or banish the oil entirely, air-fry the potato into something dry and pale, and let everyone at the table politely agree it tastes “pretty good.” So when I saw the claim out of the University of Illinois, that you can drop a potato into a full bath of hot oil and pull it out holding less of that oil, my honest first reaction was disbelief. Fry it in oil, get less oil? That is not how soaking works.

The claim landed on July 29 through a University of Illinois release under a headline promising “much healthier” fries. The work under the headline is real, and kind of beautiful: a study in the Journal of Food Science from Yash Shah and Pawan Takhar’s lab, with Juming Tang’s group at Washington State, who built a custom fryer that beams microwaves straight into a bath of oil heated to 180°C while a potato strip cooks, and then measured what happened inside a single fry. But “much healthier” is the press office talking, not the data. Hold that thought.

The biology of a fry is stranger than the plunge into the fryer makes it look. What actually greases a French fry isn’t the dunk. When the potato hits hot oil, the water inside flashes to steam and comes roaring out, and for a while that outward rush of vapor holds the oil at bay. The fry is pushing back. But as the potato dries, the physics flip. The empty pores left behind start to pull, developing a kind of internal suction, and that suction keeps drawing oil inward, much of it after you have lifted the fry clear of the fryer, as surface grease gets sucked down into the crust. Most of a fry’s oil, the Illinois team notes, gets drawn in under that negative pressure.

So why would heating a potato from the inside change how much oil it drinks? I kept turning that one over. Ordinary frying heats from the outside in. Microwaves heat the whole fry at once, volumetrically, which cranks the internal pressure higher and keeps that outward push going longer. They tracked it with sensors threaded into the center of a single fry: at the same 2.45 gigahertz your kitchen microwave already uses, peak internal pressure hit 24.9 kilopascals against 13.8 for conventional frying, and the oil content barely climbed even as the fry dried out. More pressure inside means the fry spends more of its cook shoving oil away instead of drinking it in.

And this isn’t just an Illinois lab artifact. A separate study out of Tikrit University in Iraq, frying potatoes in corn oil, found microwave-fried fries soaked up roughly a third of the oil that deep-fried ones did, about 10 percent by weight against 30 percent. Two labs, two oils, same direction. As a piece of food physics I find it genuinely lovely: you are not fighting the oil with less oil, you are out-pressuring it.

Which brings me back to “much healthier,” a phrase doing an enormous amount of work. Less oil is one number on a fry, and it is not the one I would worry about most. Start with what the Illinois team never did: taste the thing. They say so plainly, that comparing the flavor and texture “was not a focus” and would need its own study. And the texture they did measure came out frequency-dependent: crunchier only at 5.8 gigahertz, the pricey frequency, and softer than an ordinary fry at the cheap 2.45-gigahertz setting that kept the most oil out. When the Iraqi team actually fed microwave-fried fries to ten people, the tasters preferred the deep-fried version on color, aroma, flavor, and overall, and found the microwaved ones hard and closer to a potato chip than a fry. So two labs, and they cannot even agree on whether microwaving leaves the fry softer or harder. That is what an untasted method looks like.

Then there is acrylamide, which is the compound I actually think about when I think about fries. It forms when starchy food browns at high heat, and the International Agency for Research on Cancer lists it as a probable human carcinogen. The Illinois study did not measure it at all. The Iraqi one did, and here the microwave bought you nothing: microwave frying produced as much acrylamide as deep frying, and at each step a shade more, not less. Pressuring the oil out does nothing for the carcinogen, and the rapid internal heating that keeps the oil at bay may even nudge acrylamide the wrong way.

The last thing the “healthier fries” headline skips is who this is for. The paper is not describing a kitchen gadget. It is a lab prototype, funded by the USDA, and the practical pitch is explicit: retrofit the continuous fryers on factory floors with microwave emitters so manufacturers can fry faster and cheaper. A roughly 40 percent cut in frying time is the real selling point, and it is aimed at industry, not your stovetop. “Healthier for you” is just the version of that story that travels.

I do not want to be sour about this, because the mechanism really is elegant, and I will be first in line to read the study where somebody finally tastes these fries and measures their acrylamide honestly. But I am not rearranging a single thing in my kitchen over it, and I would bet against greaseless drive-thru fries for a long time yet. When I want fries, I will make them at home, salt them, eat them hot, and enjoy them as the occasional pleasure they are, not because a magnetron pressed a little oil out of one in a lab.

Sources

  1. ScienceDaily / University of Illinois – “New microwave frying method could make french fries much healthier” (2026-07-29)
  2. Journal of Food Science – Shah, Zhou, Tang & Takhar, “The Effect of Conventional and Microwave Frying on the Quality Characteristics of French Fries” (2025)
  3. Functional Foods in Health and Disease – Ahmed, Mohammed & Hussin, “Acrylamide content and quality characteristics of French fries influenced by different frying methods” (2023)