Food fad or science – or both? Why cooking with water may help slow ageing

Dr Michelle Davenport says her grandmother is 95 and doesn’t have any wrinkles. Skin smooth as a dewdrop. She came to America from Vietnam, and attributes her youthful complexion to rarely, if ever, eating out at restaurants: not on birthdays, anniversaries or other special occasions.

“She was always telling me: ‘Don’t ever eat out, eating out is super bad for you,’” says Davenport on the other end of a Zoom call. “So we always had to cook at home. And when she did cook, it was always water-based: steamed meat, stews and lots of vegetables.”

Davenport, 39, is a scientist and registered dietician based in San Francisco whose work focuses on slowing the deleterious effects of ageing. She argues that this can be accomplished by cooking mostly with broth and water. On her Instagram page, which has nearly 200,000 followers, you’ll find recipes for dishes like collagen-rich oxtail phở, green curry salmon, steamed eggs and gà hải nam (the Vietnamese version of Hainan chicken, a recipe passed down directly from Grandma).

Cooking this way, she says, mitigates the creation of advanced glycation end products, or AGEs, formed when food is cooked at high dry temperatures, like over the grill or in an air fryer.

Davenport remembers her eureka moment clearly. In 2012, she was pursuing her PhD in nutrition at New York University. “Like a lot of Asian families, I have a lot of family members that have histories of diabetes, mostly on my mom’s side,” she says. “So I was always really interested. It’s what I wanted to study.”

In one class, a professor very casually said something that altered the course of her career: “Everyone knows that AGEs in processed western foods are killing us.” Davenport bolted up in her seat: “I was like, um, what?”

“I had never heard anything like that. And then … he never said anything else about it again,” she says, laughing. “But I started digging into the topic and I was like: ‘Oh my God. How is no one talking about this?’”

What are AGEs?

Advanced glycation end products are a group of compounds created when proteins or lipids are exposed to sugars. People encounter them regularly in the western diet, where they are typically generated during the cooking process via the Maillard reaction, or when food is blasted over high heat. (Think: the crust on a good steak.) A lot of ultra-processed foods, like cheese puffs and breakfast cereals, are also cooked this way.

Once in the body, AGEs do one of two things. They can crosslink with a protein, which causes plaque buildup in the body – this can clog arteries and reduce healthy blood flow. Or they create inflammation through receptor binding. It’s why researchers consider AGEs a powerful biomarker for oxidative stress, which causes cell and tissue damage, and inflammation.

During the past decade, there has quietly been an abundance of scientific literature suggesting that AGEs are the common denominator for a lot of modern health woes. “We and others have demonstrated that a diet high in AGEs is associated with the development of many chronic non-transmissible diseases, which are a plague in the modern western world,” explains Dr Jaime Uribarri, a nephrologist and researcher at Mount Sinai, “including insulin resistance, obesity, cardiovascular disease, kidney disease, dementia and cancer”.

Davenport ended up writing her NYU dissertation on the topic (Uribarri was one of her advisers) and quickly realized that certain kinds of Asian cooking methods – like the recipes her grandmother taught her – were well-suited for minimizing AGE levels. “Basically, AGEs are responsible for total body ageing,” says Davenport, “but it’s crazy that it all comes down to these compounds that are so easily preventable.”

“Most negative effects of so-called ultra-processed foods are related to their content in AGEs,” Uribarri says. Introducing an AGE-restricted diet, “essentially obtained by changing the culinary technique rather than the content of foods”, has been shown to help with many of the biomarkers of disease.

How to minimize AGEs

As Davenport tells it, there are two main ways to dramatically reduce the amount of AGEs in food.

The first is using water and broth to cook, which inhibits the Maillard reaction. “While chefs are trying to get everything as dry as possible to get that sear, I do the opposite,” says Davenport.

The second method is to use acid for marinades – particularly in meat. “I mean, sometimes I want grilled food,” Davenport says. “Like on the Fourth of July, I wasn’t going to be eating soup.”

So, if you’re going to throw meat on the grill, “studies show that even if you just marinate for 15 minutes, it’s still a significant reduction in the amount of AGEs”, she says. “It’s a very simple fix.” One of Davenport’s most popular recipes, for steak with chimichurri sauce, uses this technique.

Davenport, who founded a food startup focused on healthy children’s meals, then sold it in 2019, decided to start posting recipes designed to minimize AGEs on Instagram. Things just kind of snowballed from there. “Last year, when I started, I was like, who’s going to want to hear about soup? That’s so boring,” she said.

“I feel like my cooking style is kind of gross,” she adds. “I get really up in the meat. Not everyone wants to touch oxtail. It’s kind of gag-inducing.”

She suspects part of the reason her work is resonating is because it speaks to a broad audience, and not just the Asian diaspora or people who do yoga six days a week. “I think a lot of people in the world cook this way, especially in Europe and Africa,” she says. “I get so many random messages from people being like: ‘Oh, yeah, we also had this kind of stew or oxtail soup.’”

Is there a limit to how many AGEs you should consume a day?

“There are no clear guidelines on exactly how much of these AGEs you should be consuming a day, but I try to keep it as low as possible,” she says. “Some people say less than 15,000 AGE units, and there are databases out there, but generally I feel like if I’m just eating mostly water-based cooking most of the time, then once in a while [it’s OK] if I go out to an American restaurant where the menu is all AGE stuff. I’m not going to sweat about it too much.” (A pan-fried steak, for example, contains roughly 10,000 AGE kU/Ls, or kilounits per liter. Marinating a steak, on the other hand, cuts that AGE count in half.)

Davenport does most of the cooking at home for her husband and two young children. She subscribes to the 80/20 rule: “healthy” most of the time, while leaving some wiggle room for fun stuff.

But how does she approach cooking with kids, who can often be picky eaters?

“Thankfully, they love soups and stews,” she says. “The other night we had hot pot. It’s cool because they can kind of pick what they want from there, and it’s fun for them to learn how to cook things.”

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Her husband, an ER doctor from Hawaii, can be slightly more challenging: “He’s so American. He just really wants barbecue all the time.”

Davenport doesn’t claim that mitigating AGE intake is the only or most important health metric, but rather another piece of the health equation. “I’m not saying [my method] is a panacea,” she says. “This is just another thing to consider.”

She doesn’t consider herself an influencer; unlike others in the health space, the academic in her is rigorous about citing her sources. But she is happy that her recipes and methods are resonating with people who are interested in their health and eating habits.

“I’m not a biohacker,” she says, shrugging. “I’m more of a grandma who cooks soups and stuff.”

• Chris Gayomali is a writer and editor based in New York City. He publishes the health and wellness newsletter Heavies