It’s long been clear that we don’t all respond the same way to the same dietary interventions.
Personalized nutrition works–but NOT for the reasons we think. This week, let’s take a look at dietary fads that claim to be tailored to your specific needs.
Nutrition Diva is hosted by Monica Reinagel. A transcript is available at Simplecast.
Have a nutrition question? Send an email to nutrition@quickanddirtytips.com or leave a voicemail at 443-961-6206.
Find Nutrition Diva on Facebook and Twitter, or subscribe to the newsletter for more diet and nutrition tips.
Nutrition Diva is a part of Quick and Dirty Tips.
Links:
https://www.quickanddirtytips.com/
https://www.quickanddirtytips.com/nutrition-diva-newsletter
https://www.facebook.com/QDTNutrition/
https://twitter.com/NutritionDiva
https://nutritionovereasy.com/
Hello, I’m Monica Reinagel, and you’re listening to the Nutrition Diva podcast, a show where we take a closer look at dietary fads and dubious claims so that you can make more informed decisions about your own health and nutrition.
Over the years, I’ve looked at a whole slew of dietary fads that could be grouped under the general heading of personalized nutrition.
There was the blood type diet, for example, which claimed that you should either include or avoid various categories of foods based on whether you had Type O, A, B, or AB blood. A different dietary pattern was recommended for each blood type. And any of them would constitute a substantial nutritional upgrade compared to the typical American diet. But there is very little research to support any connection between one’s blood type and one’s ideal diet.
There were also popular diets based on body shape—one diet for those with pear-shaped figures, another for those with apple-shaped bodies, and so on. And, as with the blood type diets, following any one of them would result in a much healthier diet than most people were already eating. But, again, the “science” supporting the different diets was speculative, at best.
Another whole category of personalized nutrition involves testing your blood for the presence of antibodies, which would allegedly reveal subtle food sensitivities that were responsible for your symptoms or your inability to lose weight. Except that these tests are not considered valid indicators of an actual food sensitivity.
To be clear, food intolerances do exist. It’s just that these sorts of tests are not a reliable way to identify them. There’s a very high rate of false positives (where the test says you are sensitive to a food that you actually tolerate just fine). As a result, they usually result in overly and unnecessarily restricted diets.
But the appetite for personalized nutrition continues unabated! More recently, advances in genomics and microbiomics have led to an explosion of new products and services that claim to give you a personalized dietary prescription based on an analysis of your microbiome or your DNA.
And I get it! It’s long been clear that we don’t all respond the same way to the same dietary interventions. Some people do really well on a higher fat diet. Others develop high triglycerides or cholesterol on the same diet. Some people lose more weight when they reduce carbs. Others lose more weight when they increase complex carbs and reduce fat.
If these differences are genetic, maybe we could skip some of the trial-and-error and zero in on the best approach for each unique individual based on their DNA. Several large studies were launched to validate this approach and several large companies were launched to monetize it. The studies, unfortunately, have been less than convincing. The monetization of DNA-based diets, however, continues apace.
And here’s the crazy thing: Even though the science does not really support them, these personalized dietary prescriptions may actually improve people’s health. Why? Because we believe they will.
This summer, researchers from McGill University published the results of a study in which all the subjects were given a placebo treatment. But some of the subjects were put through fake genetic testing and then told that the placebo treatment had been customized based on their results. The placebo treatment was actually exactly the same for all of the subjects. And, true to the placebo effect, the treatment did have some positive effects in both groups. But it was significantly more effective in those who believed that their treatment had been customized based on their genetic analysis.
In one fascinating side note, the researchers found that those who had “a stronger desire to be seen as different from others—based on the results of a personality questionnaire—experienced the largest benefits, but only when told that the [treatment] was personalised.”
Similarly, selling someone a dietary prescription that is based on their genetics may well produce better results than the same dietary prescription offered without the halo of personalization. People may feel more motivated to follow a prescription that’s ostensibly tailored to their unique physiology. They may feel better when following it because they believe it’s personalized. And perhaps that’s enough to justify the utility (if not validity) of personalized dietary advice.
Except that knowing does not always result in doing. Especially once the novelty wears off. I work with people all the time who know full well that the dietary choices they are making are not supporting their health.
I think we often kid ourselves that having more information will result in making better choices, especially if that information is highly specific to us. But as most nutritionists and dietitians that work with people one-on-one will tell you, very little of our counseling consists of telling people what they should and shouldn’t eat. It ends up being mostly about helping people figure out how to bridge the gap between knowing and doing.
Despite the variances between individuals, there are some universal truths. We don’t have to sequence your DNA or analyze your microbiome to know that foods high in added sugars, fried foods, and highly processed foods are not ideal for the human body. If these foods are still a big part of your diet, it probably makes sense to start eliminating them before spending $500 to find out whether your intestinal bacteria prefer apples to oranges.
If you’re not willing to take these first obvious steps toward a healthier diet, how much good would a personalized dietary prescription based on your genes really do in the long run?
That’s not to say that the ideal diet is a one-size-fits-all solution. But I think it’s even more important to optimize for non-biological factors such as your preferences, lifestyle, and priorities.
My friend Jay, for example, struggles with a strong genetic predisposition toward high cholesterol and diabetes. He really wants to manage these issues without medication as much as possible, which means that for him, diet and lifestyle are key.
Interestingly, he has had success with two diametrically opposed approaches. A few years ago, when his blood sugar levels were starting to cross the line from pre-diabetic to diabetic, he took the low-carb route. He eliminated virtually all sugar and most grains, starchy vegetables, and legumes. His diet was mostly meat, eggs, and vegetables. His weight and blood sugar dropped impressively. But after a year or two, they started to creep back up. Part of the problem was that he found it difficult to sustain a strict low-carb lifestyle long-term.
And so, he did a complete U-turn and switched to a vegan diet. Although he still moderates sugar, he now builds his meals around grains and legumes: foods that were mostly off-limits on a low-carb diet. This too worked like gangbusters, even though it was pretty much the complete opposite of his previous approach. He lost weight, his cholesterol improved dramatically, and his blood sugar dropped enough to keep him off meds.
Both approaches require giving something up. But over the long haul, Jay was more willing to give up meat and eggs than he was to give up grains.
Which of these approaches would a DNA or microbiome test have suggested for Jay? Who cares? Both approaches worked for his body. But one worked much better for his preferences and lifestyle, making it far more sustainable. Winner, winner, chicken-free dinner.
I predict that the science and technology around personalized diets will continue to evolve and become more accurate. But knowing what diet is best for us doesn’t necessarily make it any easier to follow it.
Here are three ways to personalize your diet.
What sort of foods do you enjoy? Which are you indifferent to? Are your tastes more adventurous or conventional? Some people would be happy to go for the rest of their lives without potatoes as long as they can have steak. Others are exactly the opposite. Some love exotic flavors and ingredients. Others prefer plainer fare. All of these can be important clues to your ideal dietary approach.
That’s not to say that you can never branch out and try new things, but an approach that is completely outside of your comfort zone is going to be hard to sustain for long. As soon as things get busy, we’re likely to revert to our more familiar and comfortable patterns. So let’s start by creating the healthiest possible version of that baseline.
It’s not just about your taste preferences, though. It’s also important to consider how eating a certain way makes you feel. For example, compare how you feel after eating animal foods, which tend to provide more protein, and how plant-based meals, which are usually higher in fiber, make you feel.
One day you might have eggs and vegetables for breakfast and top your salad with grilled chicken at lunch. Another day you could have oatmeal with nuts for breakfast and top your salad with garbanzo beans. Then, pay attention to how you feel throughout the day. Do you feel energized or sleepy? How satisfied are you after eating? Does your digestion feel more sluggish or efficient? How soon do you get hungry? Are you cruising through your workouts or feeling underpowered?
Finally, it’s important to consider what, besides your health, really matters to you. Are you a competitive athlete? An environmental warrior? Is food and cooking an important part of your social and cultural rituals or something to be dispensed with as quickly as possible? Your diet needs to align with more than your DNA; it also has to be harmonious with your other priorities and values.
The best diet for you is the one you can follow. Our genes and microbiome may hold some clues as to which dietary approaches will produce the best biological response, but few of us make dietary decisions based only on our biological needs. A reasonably healthy diet that you can happily and comfortably sustain is better than the biologically “perfect” diet that you can’t or won’t follow.
The details don’t matter if the basic foundation is missing. You don’t need a microbiome analysis or DNA test to know that cutting back on added sugars, refined carbohydrates, and other highly processed foods and eating more nutritious whole foods will improve your health.
All of this is baked into the approach we take in the Weighless program, by the way. If you’re looking for more support for healthy weight management, please check out the tools and resources that are at weighless.life.
If you have a question you'd like me to answer, you can email me at nutrition@quickanddirtytips.com You can also leave me a message at 443-961-6206
Nutrition Diva is a Quick and Dirty Tips podcast and is supported by a fantastic team, which includes our Director of podcasts, Adam Cecil, audio engineer Nathan Semmes, Davina Tomlin runs our marketing and publicity, Holly Hutchings is our Digital Operations Specialist and Morgan Christianson is our Podcast Operations and Advertising Specialist.
That's all for this episode. Thanks for listening! I'll see you next week.