Why you might want to think twice about expensive personalized nutrition plans
One of the biggest promises for nutrition in the modern age is personalization. It’s a wonderful concept — lifestyle advice that is not just the boring, generic stuff you get from dietary guidelines and exercise books, but that’s tailored specifically for you. No longer will we all have to labor under the yoke of one-size-fits-all diets, instead opting for the obviously more effective personalized version that’s exactly what YOU need.
It’s a promise that has captured our hearts, our minds, and more importantly, our wallets. The global personalized wellness market was estimated at $25 billion in 2017, and is growing steeply.
Partly that’s because in our consumerist world, where even handcrafted designs have become cliche, personalization is something that we all crave, but largely it’s because personalization is very expensive. Basic advice on how much coffee you should drink, based on your genes, might cost you $100, while detailed plans looking at multiple aspects of your life can cost more than $1,000 — and that’s not even factoring the value of your data and privacy concerns.
And while they acknowledge that their tests can be pricey, the companies selling these reports and plans argue that they are well worth their money because they work — supported by science!
The problem is, a lot of the science is very speculative and preliminary, and not nearly as solid as you might think. For example, this study is referenced as proof that genetic testing can help to personalize lifestyle advice, but it actually concludes that the evidence isn’t really very good at the moment that this is true. Maybe one day, but right now all we have is vague hope.
And even worse, when scientists test these personalized offerings in real people, the results are very underwhelming.
There’s a good chance that personalized nutrition is a waste of time after all.
The basic idea of personalized nutrition advice is simple — we are all very different, with different lifestyles, genes, likes and dislikes, and all of this effects not just what we eat but what we should eat.
For example, some people have genes that are associated with better outcomes when people eat more fat. For these people, the idea goes, a eating more fatty foods — ideally ‘healthy’ fats like seed oils — might improve health.
On the other hand, some people may have genetic predispositions to certain types of injury. This could potentially make certain exercises more risky for them, which means that they should be steered towards a different type of exercise in their plan to get fit.
But even in this simplistic explanation, you can see the problem. Some gene/diet interactions are ‘associated’ with good health, in a complex way, and acting on this ‘might’ improve health. Genetic predispositions are fascinating, but often the science is very speculative about a causal link between things like your genes and whether you’d be good at, say, jumping.
There are other elements to personalization — blood markers and personal preferences, for example — but often these follow similar trends to the genes.
So what happens when we actually test these personalized predictions?
Personalized nutrition is an emerging field that’s only been around for a decade or so, but even in that time there have been quite a few trials done on real people in the real world to see if it works.
The results have been…unimpressive.
For example, the Food4Me study, a large randomized controlled trial done across a half dozen countries in Europe that tested basic nutrition advice against special personalized advice based on genetic and blood tests. They found that, while some personalization was better than none, the difference between the kind of dietary advice you’d get from any nutritionist or dietitian in a consultation and an expensive panel of tests was nonexistent. And even the difference between personalization and standard one-size-fits-all advice was very small!
Another study called DIETFITS looked at whether genetics made it easier to lose weight on two different diets — low-carb or high-carb — and found that genes made no difference at all.
Systematic reviews — large meta-studies that combine the results of dozens of pieces of research to survey the field as a whole — that have looked at the question of personalized nutrition have also found underwhelming results. While there may be some effect for specialized tailored programs, it’s likely to be quite small if it does exist. One recent review of 12 studies on personalized nutrition plans found that there was a small benefit to weight-loss in the short term when compared with standard advice, but that after 12 months there was no difference whatsoever.
It’s also worth remembering that it’s impossible to blind people to whether their nutrition plan is personalized or not — people who get these special dietary plans almost always know about it. What this means is that it’s hard to know whether the benefits of the plans are because of the special tailoring of the plans themselves, or just whether we all think they’re more effective, so we stick to them better.
There’s some evidence that personalized nutrition plans can help people. A lot of the theories are based on really fascinating and complex science that may yet bear fruit. But studies in the real world on real people have so far failed to find much benefit from these special plans outside of the basic improvement that any dietitian can offer.
It’s possible that the benefits of personalized nutrition are nothing more than a convincing sales pitch.
What’s definitely true is that personalized nutrition is big business, and only going to grow. Even if the products are largely ineffective — remember, the evidence really isn’t great — they are still being sold to huge numbers of people across the world.
If you’re worried about your diet, the current best evidence suggests that you can avoid the shiny offers and expensive tests on personalization websites. Just book yourself in to see a diet expert like a registered dietitian — it’ll probably be just as effective and cost less than the alternative.
Don’t get too worked up about the hype.
Chances are personalization isn’t as important as you’ve been led to believe.
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