A few years back, I had the opportunity to do nutrition-based genetic testing. The company wasn’t making any weight-loss promises, but they took my DNA and gave me a report telling me lots of interesting things:
I am more at risk for iron deficiency, gluten intolerance, and lactose intolerance.
I have an innate drive to exercise (pfffft, well YEAH, this one I knew!)
I am sensitive to caffeine.
I have an increased risk of over consuming sugar. (do they know about my love of Oreos?)
I have an increased risk for achilles tendon injury. Random, I know.
Those results aren’t exactly rare. The results also told me that two out of three people have a risk variant for iron deficiency. One in two have a risk variant for caffeine. Three in ten have a risk variant for lactose. One in five have a taste preference for sugar.
Fascinating stuff, but not all that useful for someone who is mindful about what she eats and how she moves.
What is a DNA Diet?
Genetic testing isn’t new, but how DNA relates to our nutrition and food choices is really a science in its infancy. That’s not to say that results like mine are useless – but their use is definitely limited for most people.
There are diseases that we know for certain are passed down genetically – sickle cell anemia, hemochromatosis, cystic fibrosis, and many more. But using DNA to predict how a person should and should not eat to lose weight is a lot more complicated and a lot less clear-cut.
For the results I got above, I was instructed to eat iron-rich foods. Watch my coffee intake (I only have one a day anyhow, because it makes me jittery). Eat less lactose. Be mindful of my sugar intake. Stretch my calf muscles and watch certain activities that can strain my achilles. Mostly stuff I should be doing anyhow, although the lactose thing I don’t see. I digest lactose just fine, at least for now. But again, this test wasn’t giving me weight loss advice.
Now, weight loss is the latest facet of genetic testing that companies are pushing, because of course it is. So many of my followers have asked me if DNA weight loss plans are really legit, so I looked at a few of the companies, what they offer, and where the research is at right now for this sort of stuff. Here’s what I found.
The first thing I noticed is that the companies offering DNA diets for weight loss are basically all the same.
The DNA Diet Plan insists that their testing is accurate and will result in weight loss (or your money back!)
They state that “70% of factors that affect body weight are tied to your genes,” a claim that I have a lot of trouble believing, because, you know, SCIENCE.
The DNA Diet Plan
Their plan includes DNA Diet’s ‘EXCLUSIVE’ 12 Rules of Weight Loss:
Rule 1: Discover your DNA (it will inspire you!)
Rule 2: Weigh yourself weekly, no matter what
Rule 3: Eat a high protein breakfast to prevent cravings
Rule 4: Track what you eat, especially your treats
Rule 5: Use the meal plan but make it work for you
Rule 6: Stop eating at 8pm and get a good night’s sleep
Rule 7: Make an effort to exercise (don’t exercise to eat)
Rule 8: Use the 20:80 rule if dining out or ordering in
Rule 9: Restrict alcohol to 2 days a week (if at all)
Rule 10: Eat slowly, seated and on a regular schedule
Rule 11: Don’t allow stress or setbacks to stop you
Rule 12: Find reasons to fistbump
Okay, wait. DNA will inspire me? Wait, is fist bumping a genetic trait?
But these rules are totally generic, which is probably why the company says that you don’t even need to wait for your DNA results to start losing weight.
DNAfit offers the testing, plus RD counselling, presumably to accompany their generic recommendations. They boast uber-charlatan Dave Asprey among their ambassadors, which for me equals a RED FLAG X 10000!!!!
Pathway Fit, another DNA diet program, clearly had a breach on the day I was writing this, because while I was able to access their site the day before to get information, on this day all of their url links all led me to sex sites. So yeah, no thanks. If you can’t keep a handle on your website, how can you read someone’s DNA?
But anyhow, when I could actually get onto their website, I saw that they recommend one of the following diets based on your results:
Balanced: If your DNA results show that you aren’t at risk for anything in particular.
Low carb: If you’re at risk for blood sugar abnormalities.
Low fat: For people whose results show a predisposition to high LDL, low HDL, and high triglycerides.
Mediterranean: Um. Maybe for everyone?
Lactose free: If, like me, your DNA shows an increased risk for lactose intolerance.
Gluten free: If you’re predisposed to gluten sensitivity.
Again, generic. And not only that, but completely overstepping the science. Just because you have a higher than normal risk of being gluten sensitive doesn’t mean you need a gluten-free diet. Just because you have an increased risk for lactose intolerance doesn’t mean you need to stop eating lactose altogether. To even suggest these things is absolutely ridiculous and irresponsible and shows the (low) level of credibility that this company has.
Some DNA diet kits also make supplement recommendations based on your test results, and then, perhaps unsurprisingly, sell you the supplements you ‘need’. SIGH.
While each company wants to make it seem as though their testing method and range are superior to the others, the truth is that the entire area of DNA and diets and weight loss is complicated and not defined as of now.
More than anything else, the tests seem to be more for entertainment and general information.
Some people, when confronted with the DNA-based information that they’re more at risk for heart disease or other health conditions, may change their diets just based on that, and that’s a good thing.
Issues with DNA Testing
But especially for diet and weight loss, I think there are more issues than benefits associated with DNA testing. Here’s a few:
We’ve tested this before. It didn’t go so well. The DIETFITS trial in 2018 did a great job of showing us that even if someone’s DNA predicts that they’ll lose more weight on a low-fat or a low-carb diet, the results don’t necessarily translate into real life. Participants did DNA tests before the study to categorize them into a low-carb or a low-fat group according to their genes.
The outcome? There was no significant difference between the groups in terms of weight loss.
There are several variants to each gene: The way I understand it, each gene has different variants. Different DNA testing companies may test for different variants, which is why you can get different results with each company. One company might say you need to stop eating so many carbs, the other might say you metabolize carbs fine. DNA is complicated, y’all.
The science is in its infancy: Plain and simple, our knowledge and abilities are vastly limited in this area, so to say that we can make definite diet recommendations based on someone’s DNA is just wrong. That doesn’t stop the companies above from making these claims, though.
The recommendations are very broad: Seriously, most of the recommendations that these companies dole out will work for everyone. They’re just common sense.
There’s so many other things to consider: Probably most important is that just because you have a trait that says you’re predisposed to overeating sweets, or that you have trouble digesting carbs, doesn’t mean that those things are going to play out in real life.
Plus, having a ‘predisposition’ towards something doesn’t mean it’s going to actually happen.
Psychosocial determinants such as finances, work and home environment, and mental health play an enormous role in eating behavior. And gut bacteria is emerging as a significant factor in how we metabolize nutrients. DNA tests don’t consider these factors, but they can definitely override any genetic predispositions.
Does The DNA Diet Work?
While DNA-based diet recommendations may not be harmful, they’re probably not that useful either.
I wouldn’t be looking to DNA for weight loss advice. It’s more for entertainment than anything else.