First there was the grapefruit diet—promising that the tart monotony of grapefruit after grapefruit would finally reveal your abs. There were more: Atkins, Blood Type, Dukan, Whole30, each with its own claim that a one-size-fits-all regimen is the answer to longevity and better-fitting pants. But what if we could determine, away from the citrus fruit mongers and peppy SoulCycle fanatics, the best way to live a healthy life? What if the answer is personal, buried in your genes?

Sign up to get Backchannel's weekly newsletter.

A decade ago, companies such as 23andMe entered the empty, unregulated field of personal genetics with a limited purpose: to satisfy their customers’ curiosity. Their tests provided answers to the few, narrow questions that could be answered by genes—some fun (How much Neanderthal DNA do I have? Are my ancestors really from Spain?), and some serious (Is my child at risk for Tay-Sachs?).

Like the questions, the tests were finite. You read your report and curiosity satiated (actually, we’re Greek!), put the results away, letting them gather dust in a drawer.

No longer. A new breed of startups has arisen, based on the premise that there are innumerable ways to spin our genes into concrete answers. The organizing body behind a cluster of these companies is Helix, a genomics startup that plans to launch a veritable app store of genetic data this summer. Where other companies have used DNA analysis for a one-off test, Helix will house results so that they can be shared with any number of partners, which will in turn use those results to offer answers to any number of questions—from personal preferences (companies such as Exploragen will offer DNA-tailored dining experiences) to family planing (Jump provides cute predictions of what your future offspring might look like).

“The next great discovery is you,” Helix’s website reads.

As the field has grown more sophisticated, so have the questions. A slew of genetic tests has created a cottage industry of self help, promising to spin results into action plans. Imagine if, instead of blindly hopping from Atkins to Whole30 in the hopes that one will be the secret to weight loss and glowing skin, you could feed your DNA and an app would sort out the answers ahead of time. If you were at risk for iron deficiency it might tell you to eat spinach; if your Achilles tendon were at risk for a tear it would tell you to stretch your calves before running.

It’s a tantalizing promise for the Goop generation: personally optimized wellness with a regimen catered to your DNA. These companies claim to be able to tell you the secret to getting in shape—which is exactly what fitness fads have failed to do for years. And that secret, the people behind these startups say, has been hiding in your genes all along.

A quest to live an optimally healthy life might begin with some experts. A personal trainer or a nutritionist can advise you on the best ways to exercise and eat. But Avi Lasarow, the CEO and founder of DNAfit, argues that these experts can only go so far, given that their regimens are based on what has worked for other clients in the past. “When you have a genetic test, it guides you much better into what would work for you and what wouldn’t,” says Lasarow, whose startup offers tests for diet, fitness, and wellbeing, priced between $159 and $399.

Making what Lasarow calls “the right choices” requires information—which companies like his make it easy to get. For a few hundred dollars you can purchase a spit test. With a quick swab of your inner cheek, lab technicians have what they need to make copies of your DNA and then fracture those copies into manageable segments. A company sorts through your genetic variants (called single-nucleotide polymorphisms, or SNPs) that correlate to specific traits. After a few weeks you get the results through an online portal or in a PDF, showing the traits in your DNA that have health implications.

Though DNA analysis is a standardized process, each company picks the variants that it thinks provide answers. One company might decide that one variant signifies caffeine sensitivity or the likelihood that you might feel hungry after eating a full meal; both translate easily into advice. (Lay off the caffeine! Stop eating even if you’re still hungry!) Other results might help tailor a workout. Someone with an SNP that correlates to difficulty building muscle might add strength training or additional supplements.

Of course, geneticists have argued ad nauseam that it’s impossible to trace a trait to a gene in a direct linear process. Though some genetic variants are solidly associated with particular traits, for more of them the evidence is mixed. And even if you assume that all the loose associations scientists have found between variants and traits are correct, they don’t fully explain why humans vary so much. Alun Williams, a reader in sport and exercise genomics at Manchester Metropolitan University, told me that tying traits to DNA is like absorbing a book by reading only one word per page—you have information, but at the end you have no idea what the book was actually about.

Throughout a person’s life, environmental forces, such as how frequently you exercise or what you eat are constantly changing your genome. In short, fitness, like other complex traits including height and alcoholism, doesn’t come down to just a handful of genes—there could be hundreds or thousands that play a part. The gamble becomes even bigger when it comes to interpreting the data, linking a variant to a trait and an actionable item. Medical news site Stat News conducted an investigation of five leading genetic tests for fitness; the results were contradictory.

And yet humans have drawn sharper conclusions from less. We trek to palm readers for advice on how to regroup after a breakup and frequent Astrologyzone.com to decide the luckiest day for a business meeting. We continue to mine ourselves for answers, as if the right process will offer some secret self knowledge—information in the universe that, once revealed, will lead us to our destined partner or help us overcome a traumatic loss.

Startups are banking on the idea that information—of any sort—equals power. “One of the most significant things we realized is how much more empowered people are when you deliver them this level of personalization,” says Daniel Reardon, the CEO and cofounder of Fitness Genes, which offers genetic-based diet and workout suggestions for between $199 and $449. “There are cohorts in the population who are looking or more scientific approaches to getting in shape and losing weight.”

When I told Jim Evans, a professor of genetics and medicine at The University of North Carolina at Chapel Hill, that I had found a list of personal genomics companies, he replied: “Take a screenshot of that and come back in a year or two. I would predict strongly that there would be little overlap.” Indeed, given the number of new fitness-app companies popping up, a surprising number are unsuccessful. Since 2009, a number of big-name companies, including Existence Genetics and industry darling deCODE, have gone bankrupt.

You don’t have to dig deep in an online search to find skeptics in the fitness community. A number of companies, including DNAfit and Fitness Genes, have sent their kits to well-known fitness bloggers for them to review. On her blog The Blonde Ethos, Natalie Goodchild tried three genetic tests. She found the results interesting but not particularly helpful. She wrote that she worried that people would consider the results prescriptive when they aren’t. Other bloggers such as Tim of Shrinkinguy Fitness and Andrew Shanahan of Man v Fat have reached similar conclusions: Genetic information is interesting but far from transformative.

Yet the more data companies collect, the more likely they are to spin interesting conclusions about the link between genes and fitness. Earlier this year DNAfit published a peer-reviewed clinical trial showing that resistance training is more useful for athletes with certain genetic variants; Lasarow says DNAfit has more, bigger studies in the works. The company has fostered partnerships with several English Premiere League teams to conduct studies on mental toughness as well as universities in the United Kingdom for broader-reaching studies. (To move the field of personalization forward, counters Susan Hahn, a neurogenetic outreach specialist at clinical lab company Quest Diagnostics, these studies will have to include many thousands of people and almost an unfathomable amount of data about participants’ genes, habits, and behaviors.)

Moreover, the advice doled out by the tests seems harmless—it's hard to find fault with “eat more greens” or “drink lots of water”—but anything taken to an extreme can have side effects. Athletes who put too much credence in the results could overcompensate, making them more susceptible to injury. “There is the chance that people could put themselves in harm’s way, or put more trust in the info, than is deserved under the circumstances,” Hahn says.

There’s also the risk that what started out as a fun piece of information could uncover something serious. For example, several companies test for a gene known as APOE, which some studies have associated with obesity. It has also been associated with a greater likelihood of developing Alzheimer’s. “That’s probably one of the most stigmatizing genetic results a person could get,” Hahn says.

It’ll take time to get to a point where we can tailor a person’s wellness regimen to their DNA. The success of these companies, however, isn’t really tied to that. What matters most is if they become indispensable to our lives, giving us satisfying responses to questions about ourselves that would otherwise be left unanswered.

If we find them useful, illuminating, and profound, we’ll continue to feed them our DNA and follow their offerings. At best, it’s an insightful way to live a better optimized life. At worst, it’s easier than eating grapefruits.

Creative Art Direction by Redindhi Studio

Illustrations by Andrew Joyce