The world is swimming with health and diet advice and a lot of it lacks evidence or expertise. So how do you know what to believe? Claire Turnbull defines five questions you should ask of any piece of advice before following it.
It has never been easier to access information about health and wellbeing. With social media, podcasts, books, magazines, documentaries, online programmes, inspirational emails and “what’s new” events, everywhere you turn there’s always something different to learn and understand.
Yet despite the volume of information now available, it often feels like it’s only getting harder to figure out who or what to trust - because so much of what we hear is conflicting.
One moment someone you follow on Instagram is telling you that carbs are evil and should be avoided at all costs, and the next minute you hear a podcast highlighting the importance of carbs for sleep and how wholegrains fuel your gut bugs.
Then you read a blog that insists hormones have nothing to do with your weight, but at a menopause event with friends you’re told hormones are half the problem, and that if you don’t address them, how you exercise and eat will make little difference.
Huh?! How confusing is that?
This is the world we now live in. One that often feels like an overload of information. So how can we navigate this messy terrain without losing our minds yet still keep ourselves well?
This is something I’m very passionate about, having grown up in the medical world. My dad’s a doctor, my mum a nurse, and my older brother a pharmacist and anaesthetist. Hospitals have always felt like my second home, and for a long time I thought reading medical journals at night was what everyone’s family did.
I was taught from a young age to question what I hear, to consider the quality of the health information I tune in to, and to remember that information changes over time. Skills that I now consider more important than ever.
So before you adopt a piece of advice as gospel, here are five questions to ask about the source:
1. What are the qualifications of the person offering the advice?
In nutrition, this is a big one. The word nutritionist in New Zealand isn’t protected, so anyone can call themselves one, even without any formal qualifications.
Someone who has done a 12-week course may describe themselves as “qualified,” but compare that to a New Zealand Registered Nutritionist or Dietitian, who will have completed between three and five (or more) years of full-time study, often with a master’s degree.
Registered health professionals are bound by a code of ethics, must document and prove ongoing competency, and demonstrate that they’re keeping up to date with the latest research to maintain registration.
While most people operating in the nutrition space are well-meaning, there’s a wide range of knowledge and experience, something you, as a consumer of information, need to be aware of.
This applies across the broader health space too. Not all "doctors" you hear on podcasts or social media are medically trained; they may have a PhD, which is an amazing achievement, but not one that qualifies them to give medical advice.
2. How evidence-based is the information?
A lot of health information online is inaccurate. One study of Instagram accounts with more than 100,000 followers found that around 45% of nutrition posts were inaccurate, and only 6% were rated as good quality.
TikTok is no better. A recent review found that 97% of videos about weight loss, muscle gain and detox supplements offered no scientific backing at all.
While the exact percentages vary across studies, the bottom line is clear: much of what’s shared online is based on opinion or personal experience rather than credible, balanced, evidence-based information.
While it’s great that people want to share what works for them, following opinion-based advice can sometimes cause harm; maybe one person's approach isn’t also right for you as an individual; maybe what appears effective immediately isn't good for your body long-term; or because the suggestions are so restrictive or obsessive that they could negative affect your mental health.
Remember that everyone is different, and health advice should be tailored to the individual with consideration to their age, stage, medical history, family history, lifestyle, and personal circumstances.
As a big fan of podcasts and books myself, I see a lot of variation in this space too. Most of what I listen to is conversations with credible health professionals, but even then, experts can hold different views and sometimes take a single idea to the extreme by cherry-picking research to make their point.
It’s also worth remembering that one “new study” rarely changes everything we know about a topic. Not all evidence is created equal. Some studies are small, flawed, or have limitations – so keep your eyes open if you’re following someone who pushes one point to the extreme.
3. What’s the incentive for the person sharing the advice?
There are many people in the health and wellbeing space genuinely wanting to make a difference. But this is also an industry where there’s a lot of money to be made.
If the advice you’re hearing is tied to buying something, it’s worth pausing. Not everyone’s moral compass points in the right direction when there’s profit involved.
Be particularly wary of those who use fear in their content. It’s a great way to get traction, especially on social media where algorithms reward engagement over truth. If someone is claiming that everything you know is wrong and they’ve discovered a “magic secret,” and the solution conveniently involves buying their product, please have your BS meter turned up to high alert.
4. Is this the latest information on this topic?
Science evolves, and credible information changes over time. We used to think eggs increased cholesterol, for example, but as more robust research has been done, we now know that’s not true for most people.
That doesn’t mean health professionals were lying to you before; it just means that as we learn more, recommendations shift. Unfortunately, this natural evolution is often used by those with little understanding of science to discredit legitimate experts who are simply sharing the best evidence available at the time.
5. Is the person offering this information biased?
Even experienced health professionals bring their own perspectives, shaped by their personal experiences and beliefs. When someone gets very niche in their area of expertise, they can sometimes become so focused that they lose sight of the bigger picture.
When I come across new information, I always take a moment to consider the background, experience and life stage of the person sharing it.
For example, just like it’s tricky to take parenting advice from someone who’s never been a parent, if you’re in your 40s or 50s juggling work, family and mid-life changes, health advice from a younger influencer with a very different lifestyle might not always be the best fit for you – even if it’s well-intentioned.
In summary, before jumping into a new diet or health trend, it’s worth asking:
Who’s saying this? What are their qualifications? What is the evidence? What might they be trying to sell? And most importantly – does this really apply to me?
Claire Turnbull has a BSc (Hons) in Dietetics, is a New Zealand Registered Nutritionist, bestselling author, and speaker. If you have a question or topic you'd like Claire to address, you can contact her here.
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