Why Genetic Testing for Weight Loss is a Huge Waste of Money

TL;DR Companies that use genetic testing to tell you what you should be eating based off your DNA (like Habit) are a waste of money. They are based on new, largely untested research and claims, and simply cannot offer you a worthwhile analysis based on an at-home DNA kit.

Ready for the long version? Here we go.

Skepticism Around Genomic Biology for Diet

“We still don’t have the ability to accurately predict the most healthy diet for an individual … with or without the use of genomics,” said Rasmus Nielsen, a geneticist at the University of California Berkeley. As Lund University genetic epidemiologist Paul Franks put it, “The concept is probably not quite ready for public consumption.” –Vox

Not only is there a HUGE amount of skepticism surrounding the science that backs up Habit’s (and companies like it) claims, the company itself won’t release its algorithms and hasn’t tested its methods in clinical trials. Fun fact: Habit isn’t regulated by the FDA, so it didn’t have to go through preliminary studies before launching.

More notable research from Vox:

 “For most human beings, this information isn’t relevant. It’s not going to benefit us any more than the basic health advice.” –Tim Caulfield, a health policy researcher who has been tracking personalized medicine since the 1990s.




“At the end of the day, if we really could get the majority of the population to eat wholesome real foods most of the time — regardless of macronutrient composition — most of the nutrition-related problems would be resolved,” said Christopher Gardner, a professor of nutrition at Stanford.


The real problem does not lie in a lack of understanding around how to eat for our genetics, but around a lack of healthy eating in general.

How Does Having DNA Information Help People Make Healthier Choices? Research Says IT DOESN’T

Beyond the science not being there, you also need to consider what the heck you plan on DOING with the information that Habit (and other companies like it) gives you, because studies show genetic DNA testing doesn’t end up having any affect on diet and weight loss for those who get tested.


In 2016, researchers published an analysis of 18 studies. These studies followed people who received doctor-ordered DNA test results about disease risks to see if the results had any affect on the participants lives.


What did the researchers find? “Getting DNA information produced no significant effect on diet, physical activity, drinking alcohol, quitting smoking, sun protection or attendance at disease-screening programs.”


One of the study’s authors said this conclusion is in line with other results, showing that getting the information “has little if any impact on changing routine or habitual behaviours.”


So I have to ask: What’s the point? What are you paying for? (The answer is you’re paying for general information you could have gotten from a Google search, an elimination diet, or from keeping a food journal. You’re also paying for information that research says you won’t use anyway.)


The Problems with At-Home DNA Kits like Habit

Can you say “User error”? Because I can, and I’m saying it over and over again about at-home testing kits. We’ve got people eating Tide Pods and you think you can get accurate, uncontaminated DNA results from an at-home kit? Plus, any time you make people read instructions that they have to follow very specifically, you’ve got to assume your margin for error is huge. People have a HARD time with reading and comprehension, and with following directions (just look at all the people who can’t follow a recipe or put together a piece of furniture), so why are we all okay with people taking their own blood samples at home? Absurd. Contamination risk: HIGH. Margin for error: VERY HIGH.

Oh, and you should be aware that while companies say they aren’t selling your information, there’s no way for you to be sure of that. And we’re not talking about your super private gmail account here, we’re talking about your very unique DNA.

OH! Another fun fact: While genetic testing can’t technically prevent you from getting health insurance, life insurance policies can use the information to deny your application. So, maybe think twice about sending off your blood samples.

My Beef with Habit Specifically

Habit markets itself as “personal nutrition for better health and weight loss.” After you get your results, you get a phone call with a nutritionist who will explain your results to you and answer any questions you may have. Christina Farr wrote about her experience with Habit for FastCompany and was largely underwhelmed. After reading her review, I’m not only underwhelmed, I’m questioning the credibility of the nutritionists working for Habit.

“Overall, it mostly felt like an especially pricey hour with a nutritionist.”

“The coaching call felt similar to other experiences I’ve had with dietitians and nutritionists, albeit slightly more personal. A lot of the advice would have made sense for anyone, although there were some useful nuggets.” -Christina Farr


“A lot of the advice would have made sense for anyone.” Let that one sink in. A company that’s built on PERSONALIZATION is giving out advice that would make sense for almost anyone. If you don’t know why this is happening, please scroll up and read the part about the science not being good enough.


Some of Christina’s other comments made me uneasy. For example, she says her nutritionist told her to switch to low or non-fat milk, which is a heavily contested piece of advice in the nutrition world.


“In the absence of any evidence for the superior effects of low fat dairy, and some evidence that there may be better benefits of whole fat dairy products for diabetes, why are we recommending only low fat diary? We should be telling people to eat a variety of dairy and remove the recommendation about fat content.” – Dr. Dariush Mozaffarian


She also mentioned Habit might add a gluten sensitivity test, which could be an error on her part, or could mean Habit actually thinks you can test for gluten sensitivity. The latter really worries me. You can test for Celiac disease, but a gluten sensitivity is just a made up term for people who are affected by gluten but don’t have Celiac, and you can’t test for it genetically. You can only test for the Celiac gene. The only way to test for a gluten sensitivity is by doing an elimination diet. So if Habit thinks it can test for that with a blood sample, I’m very concerned about the veracity of anything this company does.


Habit also asks participants to self-report on information that I’m guessing most people would either A) Lie about; B) Measure incorrectly; C) “Guestimate”; or D) All of the above.


For instance, users have to fill out information like weight, height, core waist measurement, activity level, and my personal favorite: blood pressure. I’m assuming someone who bought an at-home testing kit is also not running to the doctor for an up-to-date and accurate blood pressure reading. Also assuming the kit doesn’t come with a blood pressure kit, as well as detailed instructions on how to take your own blood pressure, so I really don’t know how this self-reporting is providing accurate information. I don’t even know what to put for activity level when I start a new workout program, and I do that all the time. There’s no way this information is being reported correctly, sorry.


Other Concerns with Using Genetics for Diet

Are people under the impression that because they are a certain ethnicity or race that they need to eat a specific way? I hope not. And if so, please read the very informative book “How Not to Die.” The research in this book explains that when you look at disease rates in different races/nationalities, like comparing a Japanese woman’s risk of getting diabetes with a Western/American woman’s risk of getting diabetes, the evidence doesn’t hold up if you account for emigration. For example, a Japanese woman living in Japan, following a traditional Japanese diet may be very low risk for diabetes. But a Japanese woman living in America eating a traditional Western/American diet may be high risk for diabetes. Your genetic makeup does not trump your diet. If you eat garbage food in high quantities, you will not be healthy, regardless of your genetics. You do not need DNA information to figure out how to be healthy.


Just listen to Michael Pollan: “Eat food. Not too much. Mostly plants.” 


Rant Over; I’ll Wrap it Up

Conclusion: Don’t spend your money on dumb stuff like Habit. I’ll leave you with one last quote from Vox:

“There’s nothing in their response that provides anything useful to help evaluate their service,” researcher Paul Franks said. [Franks] wasn’t convinced about the genes Habit was using to customize users’ diet plans, “and the rest of the information they provide seems to hinge mainly on generic information about diet and health, which a good dietitian would recommend anyway.”


You’re welcome.