I had a friend tell me the other day that he found out he can’t drink dairy.
“Oh, right. That sucks. Did you start getting stomach pains, bloating, or… diarrhea?” I asked.
“Well, my genetic test told me I couldn’t eat dairy,” he replied. “I also learned I should lift with high reps because my body type isn’t suited to strength work, and I need to do HIIT cardio to optimize fat burn.”
Oh boy, I’ve seen this before, and I never enjoy the conversation that follows. When people have already invested a lot of money in commercial ‘health’ tests, they are rarely open to hearing any criticism about them.
If you haven’t already, you’re likely to start getting hit with ads for genetic tests that claim to be able to tell you how you should eat and train.
One website says, “With our award-winning fitness response genetic markers, you’ll discover how to get the very best out of your workouts, putting the ‘personal’ in personal training.” “Discover how to build your perfect meal, with carbohydrate & fat response,” says another.
This is just the latest industry trend and I suggest you ignore them for now. The reality is genetic testing in the health and fitness industry is still in its infancy.
We’ve identified some genes that are correlated with (or partially responsible for) certain outcomes, and this is often just one of dozens.
But of course, this won’t stop these f**king marketers from jumping on the bandwagon and exaggerating their claimed accuracy for profit.
Loss of money aside, the issue is that when people get a test result, this can make them believe they are screwed when they’re not, and this can affect how they make choices. (The opposite can also be true, which is a testament to a positive mindset, but I digress…)
Here’s a specific example from my friend, Greg Nuckols, which I think highlights the issue well:
“In 2011, there was a review paper published going over different independent genes that had been found until that point that affected strength-power phenotypes.
“As of 2011, there were only 22 genes that were known. So if 23andMe is only testing for ACTN3 out of the known strength-power phenotype at the time (I’m sure there are more known now), knowing about that one gene locus only tells you about 4.5 percent of that strength-power phenotype.
“So it’s not telling you jack shit. But I’ve seen so many people get that one little bit of information from 23andMe and start ‘catastrophizing’ it. — “My genes suck, I’m not going to ever get big and strong.”
“Well for one, that’s not what ACTN3 does; it’s about shortening velocity, not about hypertrophic potential or maximum contractile force potential. So maybe if you want to be a sprinter or shot-put thrower, you *might* put some stock in it, but if you want to be a powerlifter or bodybuilder, it probably doesn’t matter all that much.
“And even if it did, it’s telling you about one our of 22 genes that may make a difference.”
(Here is the relevant clip if you’d like to listen to Greg talking about this on his podcast.)
Ultimately, these test results are just a small piece of information. I’d avoid taking them. And if you have, I wouldn’t change your nutrition or training strategy based on them.
Addendum — An Email I Received From A Reader About This
Originally this was an email I sent to my mailing list (sign up here). The following exchange with a reader may prove useful in illustrating how I think about these things, so I’ll share it here:
“Hi Andy, I splurged on a DNA test a few years ago due to curiosity. What I learned about myself was useful in one very specific way. The test said my genetic disposition was towards being injury prone and long recovery time after exercise.
“That fits very well with my own observations. I would not have connected those dots without the test, and it has changed my workout plan to include more recovery. I don’t push through a workout if those muscles (and tendons) are sore or feeling tired/worked, and I am very observant of pains and discomforts which might be budding injuries.
“I have been injured a lot through the years, and have a few chronic issues with elbows and feet (from rock-climbing and army service, respectively). I tried to train like the best and failed to understand or even listen to my own body. After the test, I have not had training-related injuries (I believe). I did, however, manage to compete at the highest levels in Kyokushin full-contact karate in the early 90s so I don’t underestimate what my body can do (or perhaps rather “could do” when it was 17-20 years old).
“Yes, I absolutely agree that we don’t know enough. That companies promise the sky and deliver mumbo-jumbo. That a DNA test is not something you change your whole life around and your other points. It might also be that those genes the test used as markers for injury risk and recovery are misunderstood of course. – Rolf”
“I don’t know whether the test is actually showing something legit, or whether it’s just coincidence, so I can’t comment on that specifically.
“But regardless of whether the results of such tests do indicate a tendency to being more injury-prone or not, it’s highly unlikely I would ever recommend people take one.
“Mindset has a potent effect on the body. This is especially true in pain science. If you tell someone they’re injury prone, that can really f**k them up. It’s better to have people believe they are no more injury-prone than the next person than think they’re either more or less so.
“People shouldn’t be doing exercises that have a high risk of injury, regardless. And people end up learning through experience when their bodies are getting the kind of soreness that signals they aren’t recovering, which will lead to injury. I don’t think there’s a way to explain it; it is always going to be highly individual.
“That said, it sounds to me like the test did help you in one specific way — it made you finally pay attention to the signals that your body was already giving you about recovery. These are probably signals that you learned to ignore through your years of training full-contact karate. (I know Kyokushin-kai, it’s brutal.)
“Thank you for sharing. – Andy”