Major new research finds there’s no one perfect eating plan for everyone

Food is confusing. Your coworker might credit the ketogenic diet for helping with weight management while your next door neighbor says it definitely didn’t work for her. In Europe, a cup of coffee after dinner is the norm, whereas if you tried to adopt the habit stateside, you know it would have you bouncing off the walls until 4 a.m.

A new study looking at data from about 1,100 people found that 60 percent of how we respond to food is totally unrelated to DNA—meaning that how your body reacts to food is going to be different than how your mom, sister, partner, friends, or favorite Instagram influencer react to it.

The study was performed by ZOE (in conjunction with Massachusetts General Hospital and King’s College London), a nutritional science company that wants to better understand how people respond to food. The research was led by Tim Spector, a professor of genetic epidemiology at King’s College London, a co-founder of ZOE, and the director of the TwinsUK study. (Note: Spector presented his findings at the American Society of Nutrition conference in Baltimore, Maryland on Monday; a rep for ZOE says the study will be published later this year.)

For two weeks, the participants (all healthy adult volunteers between the ages of 18 and 65) ate a mix of pre-set meals provided by the researchers and “free-living meals” (aka what they’d normally eat), logged their meals, and collected and recorded certain biometric data after eating. “The experiment looked at [factors] such as how their blood, glucose, and fat levels responded [after eating certain foods] and how long it stayed in their systems,” Spector explains.

“The biggest takeaway of the study is that everyone responds differently to food, so to really find out what works best for your body, it’s important to look at the individual level.” —Tim Spector, professor of genetic epidemiology

The results were surprising, Spector says. “What we saw was if you took something like a response to sugar, your glucose response, we found it’s about 40 percent genetic.” His presentation cites an example of two identical twins, where one’s glucose levels were significantly elevated in comparison to the other’s after eating the same exact foods.

What mattered more to how people reacted to certain foods, Spector says, was their very individualistic traits (like the health of one’s gut microbiome). “The biggest takeaway of the study is that everyone responds differently to food, so to really find out what works best for your body, it’s important to look at the individual level,” he says.

The next phase in his research, which starts today, involves participants in the U.S. and the UK using an at-home kit and app to monitor their glucose levels, take blood and stool samples, and record physical activity, sleeping habits, and mood—similar to what participants did in Phase 1 of the study. Then, Spector and his team can use the person’s individual data to provide recommendations on which foods to eat (and avoid) as well as the optimal times for eating.

Spector says that the goal is to make ZOE’s at-home kit and app, which was used to collect data for the study, available to the general public down the road. “As the data gets bigger, we can make more recommendations for more people,” he says. The data collected now will be used to build that consumer-facing app, which will be available in 2020. (When participants sign up, they agree that their data will be available to researchers for the study, but it will all be anonymous and not sold to any third parties.)

“The goal of ZOE and looking at this data is taking a holistic approach to your health,” Spector explains. “Someone might use it for [weight management] while someone else might want to raise their metabolism or reduce their chances of getting diabetes. It can be used for many different purposes.”

What’s clear is that only your body knows what’s best for your body; there’s no perfect eating plan for everyone. The more tuned-in to what your body is telling you, the healthier you’ll be.

Here’s what you need to know about the microbiome, including how geography affects it.