Study: Personalized diets could be future of eating

People often speak about fad diets the way they speak about exes: intensely, specifically, intimately. Atkins, Dukan, Paleo, baby food. None last, though lasting is promised, and all feed a cycle of shame for the dieter, who can never seem to make it work.

According to a recent study led by researchers from King’s College London, Massachusetts General Hospital and nutritional science company ZOE: It’s not you, it’s them. The research, which ZOE founder and Kings College professor Tim Spector expect to be peerreviewed by the end of the year, hints that one-size-fits-all diets are often doomed to fail.

The study measured 1,100 U.K. and U.S. adults, 60% of whom were twins, and their various blood markings (such as blood sugar, fat levels) in response to standardized and chosen meals. Even identical twins in similar environments varied in their responses to the same food. And the usual suspects, including fat and carbohydrates, explained less than 40% of the differences in reactions to food between individuals.

Spector and his team placed their research into an algorithm, which he said can now predict — after an at-home test — how users will respond to any given food with 73% accuracy. As early as next year, Spector said, ZOE plans to package this algorithm into an app that will allow users to search for a food and receive a suggestion of how compatible their choice might be compared to alternatives (for instance, bagel versus croissant).

“This should change consumers’ perception of food and move us away from this old-fashioned idea that it’s all about calories and it’s all about fats,” Spector said. “Our data clearly show that that is just a small proportion of the way people react to foods.” The real answer, the data shows, might relate to the microbiome (the microorganisms in the gut).

But for those living in perpetual post-breakup with fad diets, constant awareness — how a bagel will affect a body — is not necessarily a boon. Chicago therapist Taejah Vemuri, who specializes in working with patients with eating disorders, worries that the science might take an ironically one-sizefits all approach to the consumer’s response.

“We as a society would benefit from moving away from food rules and toward balance,” Vemuri said. “My hope is that these findings can help people better understand their bodies, (but) I think that it could, for some people, lead to obsession and rigidity.” She described the mindset of eating disorders cyclically: Someone believes they should eat restrictively, fails to, and is shamed into repeating the cycle again. The word for this particular brand of obsessive thinking is orthorexia, the obsession with healthy eating. Personalization, she said, might still perpetuate the cycle.

Still, Chicago therapist Casey Tanner, who also specializes in eating disorders, believes that personalization goes hand and hand with “intuitive eating,” or an individual’s ability to trust their body’s response to food — for example, feeling ill after drinking milk. She believes that personalized meal plans are ultimately beneficial (she avoids the word “diet”) and though she’s excited about the idea that nutritionists will be able to “know more information earlier” about their client, she hopes that doctors and dietitians will still work to address root issues of struggles with weight.

Northwestern medical professor Dr. Robert Kushner, whose clinical focus is nutrition and weight management, asks that individuals continue to follow the most recent governmental dietary guidelines for now. The idea that individual responses to a diet vary is an old one, he said, though Spector’s study pushes it further. He gave the example of reducing salt for hypertension; though not everyone will benefit, the guidelines are “recommendations for populations.”

“The fact that they might not work for an individual does not make them invalid,” he said. “I think we all believe that one size does not fit all, and that people are going to respond differently to diets. We just don’t have enough information yet to identify in advance who’s going to respond to what diet.”