22-07-2025
7 'healthy' food myths that actually cause more harm than good, according to a nutritionist
We've all been there: you're speaking to a friend, family member or colleague about food and they hit you with some bizarre diet advice that just cannot be true. The problem? The diet industry was poorly regulated for so long, much of the 'knowledge' people have accumulated is outdated, misinterpreted or plain wrong.
'People are bombarded with conflicting nutrition information, and unfortunately, some of the most popular beliefs are nonsense,' agrees Lynne Murphy, meal prep expert at Nutri Lean. The biggest problem with nutrition myths is that they oversimplify incredibly complex science.
'There's no magic formula that works for everyone; what helps one person lose weight might make another person feel terrible. Your age, activity level, health conditions, and even your genes all play a role in how your body responds to different foods.'
So are there any long-term diets we should be buying into? 'Instead of following the latest fad or believing everything you see on social media,' Murphy says, 'focus on the basics that never go out of style: eat plenty of vegetables, choose whole foods over processed ones most of the time, and pay attention to how different foods make you feel.'
With this in mind, Murphy has revealed the seven most common (and incorrect) food myths she sees among clients and social media users, so you know how to debunk (or ignore) them next time someone tries to 'advise' you. Prepare to be un-brainwashed.
All fats are bad
So many people had it drilled into them for decades that all fats are bad and you need to slash your intake to lose weight. But as Murphy points out, fats are actually hugely important both for keeping your body healthy and helping you stay fuller for longer, which should minimise snacking and help you slim down.
'Avoiding all fats is one of the worst things you can do for your health,' Murphy advises. 'Good fats from sources like avocados, nuts, and olive oil are essential. They provide more energy than carbs and proteins, encourage optimal brain function and, particularly in women, help the healthy production of hormones.
It's the processed trans fats and excessive saturated fats you want to limit – foods like pastries, cakes and chips. They're the ones that raise 'bad' cholesterol, increasing the risk of heart disease and strokes.'
Thinking gluten-free means healthier
We all know the type of person who insists on buying everything gluten-free or vegan because it's supposedly 'healthier'. However, Murphy says they're often getting it completely wrong. Gluten-free foods are often worse for you than their 'normal' alternatives – and can even lead to you putting on more weight.
'Unless you have coeliac disease or genuine gluten sensitivity, gluten-free products aren't automatically better for you,' Murphy says. 'Gluten-free alternatives are often higher in sugar, calories, and additives to compensate for taste and texture.'
'I see people switching to gluten-free biscuits thinking they're making a healthy choice, but they're often getting more calories and less nutrition than the regular version. Stick to the normal ones where you can – it's better for your body and your waistline.'
Juices help detox your body
Ever treated yourself to a fruit juice and justified it as a detox? Us too. Yet Murphy says it's a rookie error. 'Your liver and kidneys already do an excellent job of detoxing your body,' she says, 'so you don't need expensive juice cleanses to help them along.
More importantly, juicing removes all the beneficial fibre from fruits and vegetables while concentrating the sugar content. 'When you juice an apple, you're essentially drinking apple-flavoured sugar water without any of the fibre that would normally slow down sugar absorption,' says Murphy.
'This can cause a huge blood sugar spike, which over time increases the risk of diabetes and heart disease.'
Carbohydrates make you fat
How many times have you heard someone on a diet say they can't eat bread or pasta because they have 'too many carbs'? Well, it turns out they're needlessly denying themselves, Murphy reveals.
'Carbohydrates aren't the enemy,' she says. 'Weight gain happens when you eat more calories than you burn, regardless of whether those calories come from carbs, protein, or fat. Your body needs carbohydrates for energy, especially if you're upping your physical activity to try and shift a few pounds.
'The problem isn't the carbs themselves, but the type and amount people eat. Choosing wholegrains over refined carbs – brown pasta and bread over white – and watching portion sizes means you get all the fibre, digestive and cholesterol benefits carbs deliver, without the nasties that come with refined treats.'
Natural sugars are always better than processed
When you point out that fruit has sugar in it, there's always one person who says: 'Yes, but it's natural so it's good sugar.' According to Murphy, however, that logic simply isn't true.
'While natural sources of sugar often come with additional nutrients and fibre, your body processes sugar similarly regardless of its source,' she says. 'Honey, agave and even apples still spike your blood glucose just like the sugar you find in biscuits.'
'People think they can eat unlimited amounts of 'natural' sweeteners, but your body doesn't distinguish between honey and white sugar once it's digested,' she advises. 'Both come with the same health risks if you gorge on too much.'
You need to eat 'little and often' to improve your metabolism
Ever been told you need a mid-afternoon snack because it'll help your metabolism keep working? Sorry to say it's fake news.
'The idea that frequent small meals 'stoke your metabolic fire' has been thoroughly debunked,' Murphy says. 'Your metabolism doesn't slow down significantly between meals, and some people do better with fewer, larger meals.'
'Honestly, you're perfectly capable of going several hours between meals without your metabolism grinding to a halt. Focus on eating when you're genuinely hungry and enjoying a full, balanced meal, rather than endlessly grazing every few hours.'
Low-fat foods are automatically healthy
Rather like the gluten-free logic, Murphy points out that removing the fat content from something means it has to be replaced with something else. 'When manufacturers remove fat from products,' she advises, 'they often replace it with sugar, salt, or artificial additives to maintain taste.
'This can make low-fat versions less healthy than their full-fat counterparts. A low-fat yoghurt packed with added sugar isn't doing you any favours compared to full-fat Greek yoghurt with no added sweeteners.'
