How do I know if an expert is legit?

Red flags to look for

I've written a lot on my blog about dodgy science, and dodgy nutrition products. Most of us accept that actors and sport stars are going to be on their Instagram accounts flogging bullshit like alkaline water. We tend to expect better though from people who should've had some training in the scientific method, or at least an in-depth understanding of physiology and metabolism.

It's all the more concerning now when 93% of the population have their own podcasts where they present themselves and/or their guests as experts on a given area. I'm pretty much a boomer, so it sort of blows my mind when I have patients showing up in my clinic who have done something with their diet based on what they heard on the “Huberman Lab podcast”. This is how I find out about these people.

Photo by Will Francis on Unsplash

Now, I’ve never met Professor Andrew Huberman. I can see from the internet that he seems to be an accomplished neuroscientist. I can't see that he's ever done a single trial in humans. He certainly has no experience at all in nutrition or diet. And from what I've heard of his podcast, he draws firm conclusions about diet based on a study done in five rabbit epithelial cells.

And this is the thing about expertise. It's not about being smart. The way you get good at anything, the way you become an expert in anything, is by doing that thing over and over and over again, for probably a decade or more. Whether you're a plumber, a football player, a neuroscientist, or a nutrition scientist, the way you develop expertise in these areas is by encountering a problem, solving it and then doing this repeatedly.

And I think an added challenge in biology is that it is incredibly complex. So you will never encounter an expert “in nutrition”. Somebody might be an expert in “nutrition and Crohn's disease”, or “nutrition and athletic performance”. For example, I have a lot of knowledge in the area of nutrition and diabetes, but about nutrition and gastrointestinal health? I know enough to be able to recommend a few people in that area you should talk to!!

This doesn't mean that I am not experienced enough to know how to use clinical dietetic guidelines to help someone who has gastrointestinal problems. But the most valuable expertise is above knowing what the guidelines for your field say. It’s when you write those guidelines. It’s when research you conducted influences what those guidelines say. It’s when you’ve been seeing patients with that condition for years.

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So how can anyone recognise whether someone with a podcast (or a guest on a podcast), or someone selling you something is a legitimate expert in nutrition [and X]? If they’ve carried out published research in their area, especially as a first or last author this is a good sign. Likewise if they’ve been on clinical guideline committees. But none of these are fool-proof (ESAEMS AMHOLTAR).

I think a more fool-proof way is to look for red flags.

Photo by C. G. on Unsplash

Red flag 1: They've written a book which has as a subtle or not-so-subtle subtext the fact that this book is going to reveal the “truth” someone doesn't want you to know. Variations include “everything we thought we knew about x is wrong”. That's very, very rarely how scientific knowledge progresses. And if they've been in the field for a couple of years (and probably part-time in between being an expert in COVID and at least 5 other subjects), and have suddenly discovered that every other nutrition scientist who has spent decades in the field is wrong, your bullshit detector should be on high alert.

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Red flag 2: They profess expertise in multiple areas or across all of nutrition. Maybe I'm just dim, but to be honest I find reading and understanding all of the literature on nutrition and glucose homeostasis is quite enough. I simply don't have the time or brain capacity to read and understand everything on nutrition and gastrointestinal health, or nutrition and cancer.

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Red flag 3: They've got their own supplement, or they promote supplements. There is very little evidence that nutritional supplements (beyond a couple of very clear exceptions - eg folate pre and early pregnancy) are useful at all. So if someone is trying to sell you a supplement that does not have DOUBLE-BLINDED, RANDOMISED CONTROL TRIAL EVIDENCE that it does that thing they’re claiming it does - big red flag.

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Red flag 4: They talk about the microbiome a lot (gastrointestinal clinicians you get a pass here). Look, I get it’s fascinating. When Jeff Gordon’s group put the microbiota of conventionally-raised mice into germ-free mice (mice with a sterile colon), and found the latter gained body fat and developed insulin resistance within two weeks, it was a landmark moment in biology. And if and when this landmark discovery proves clinically useful for the management of obesity and type 2 diabetes in humans I will be as thrilled as everyone else.

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Red flag 5: They offer a solution to help you manage your weight “easily”, “effortlessly”, “finally”. For the vast, vast majority of people maintenance of weight loss via lifestyle change alone is incredibly hard for lots of reasons.

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Red flag 6: They only recommend one type of diet. Again, I can only speak for glucose control, insulin resistance, and diabetes. But a bunch of different dietary components influence multiple aspects of glucose control, and these diets can be plant-based, they can be high protein, they can have varying amounts of fat…. Different nutrients and foods have some shared and some complimentary mechanisms which can all help get you to your end goal. So if someone is recommending just one type of diet, big red flag.

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Let me close with this absolute gem from my late grandmother:

“Nicola, podcasts are like arseholes, everyone's got one”.