Nutrition myths a dietician says refuse to die

Monday, 22 June 2026

Don’t eat before midday to lose weight and lead a longer life. Eat little and often to boost your metabolism. Swapping carbs for protein is key to looking svelte… Social media, and the internet at large, is awash with often conflicting advice on what to eat to stay in shape and be as healthy as you can be.

New Zealand Registered Dietician Kylie Russell helps dispel the nutrition myths that have been doing the rounds for what feels like forever.

Myth 1: You need to eat a tonne of protein to maintain or build muscle

High-protein diets have been trending for years, with some saying we need to eat large amounts of protein at every meal - or load up on protein powder - to stop our muscles from withering away.

Probably not coincidentally, food companies have quadrupled the amount of high-protein products available over the past decade, with the investment in such products expected to rise almost 8% each year until at least 2028.

There’s no doubt protein is an essential part of our diet. We need it not only to build and repair muscle but also to help our bones stay strong and keep our brains, hearts, immune systems and skin functioning as they should.

“Protein matters, but the idea you need to eat massive amounts to see results is overblown,” Russell said. “For most people, spreading protein across the day and combining it with regular strength training is far more important than chasing extreme intakes.”

The New Zealand Ministry of Health recommends around 0.8-1.0g of protein per kilogram of body weight per day for healthy adults, and research suggests those trying to build muscle through regular resistance training should aim for around 1.6–2.0g.

“Beyond that, there is very little evidence of extra benefit,” Russell said.

Most adults in high-income countries get at least the recommended amount - about 64g a day (the equivalent of two chicken breasts) for a 80kg adult - however some scientists say that may not be enough for everyone. Over 65s and the malnourished are among those who may benefit from more.

Myth 2: Carbs make you fat

Ever felt guilty for tucking into a big bowl of pasta or pad Thai because of the carb content? The many low-carb products and diets out there certainly suggest you should.

But while low-carb diets can help people lose weight, cutting carbs is not essential for fat loss. Studies have shown that low-carb diets can be very effective for short-term fat loss, but often have similar results to other calorie-restricted diets after a year.

“People can also lose weight on more balanced eating patterns that include carbohydrates,” Russell said. “In the long term, what matters most is your overall intake, the quality of your food choices and whether the approach is realistic enough to stick with.

“Carbohydrates are not the enemy - they are an important source of energy. For many people, including the right types and portions can actually make a plan more sustainable.”

Choosing the right types is key. A study published in 2021 that followed 148,858 participants in 21 countries over nine years found that “high intake of refined grains was associated with higher risk of mortality and major cardiovascular disease events”.

The takeaway: Opt for whole grains and other minimally processed carbohydrates over white bread, rice, pasta and items made with those ingredients.

Myth 3: Fasting will fast-track weight loss and make you live longer

Intermittent fasting has surged in popularity in recent years, with proponents claiming the eating plan, which restricts when you can eat, will not only help you lose weight but also prevent - and even reverse - some forms of disease, potentially leading to a longer lifespan.

A 2025 study co-authored by researchers at Harvard TH Chan School of Public Health, which analysed 99 clinical trials across more than 6500 participants, found that, for weight loss, intermittent fasting and traditional calorie-restricted diets were on a par. However, alternate day fasting - which sees people eat whatever they want one day and fast the next - generated superior results. Those following this diet plan lost 1.3kg more than those on traditional calorie-restricted diets and improved several other body measurements related to cardiometabolic risk, including waist circumference, cholesterol and triglyceride levels, and c-reactive protein - an indicator of inflammation.

However, the researchers noted that most clinical trials lasted less than 24 weeks and that much more research is needed on intermittent fasting’s long-term health impacts.

Russell said intermittent fasting is one option to consider to lose weight and potentially extend your life but it’s no magic bullet.

“Some people like the structure of it, while others find it makes them overly hungry, more preoccupied with food, or more likely to overeat later. As for longevity, a lot of the excitement comes from animal studies. In humans, we have some evidence of benefits for things like blood sugar and cardiometabolic markers, but not strong proof that fasting extends lifespan. It is a tool, not the tool.”

Myth 4: Eating little and often is best

Those who advocate several small meals a day instead of three large ones often claim that doing so reduces blood sugar spikes, helping to reduce cravings.

However, there is no strong evidence that eating little and often is automatically better for weight loss or metabolism.

Participants in one study who ate six small meals a day showed no metabolic advantage over those who ate three large meals - but did report feeling hungrier.

“Some people genuinely feel better with smaller, more frequent meals, while others do better with three satisfying meals a day,” Russell said. “What matters most is whether your eating pattern helps you manage hunger, meet your nutrition needs and avoid feeling out of control around food. For many people, regular meals work well, but there is no one perfect meal frequency that suits everyone.”

Myth 5: We need to “detox” regularly to clean out our systems

Detox products - which include diets, smoothies, teas, workouts and supplements - claim they help remove toxins from the body, resulting in everything from better health and increased energy to weight loss.

And yet, as Russell noted, your body already has its own effective detox system - mainly your liver, kidneys and gastrointestinal tract.

“You do not need expensive detox teas, juice cleanses or restrictive detox diets to ‘clean out’ your system,” she said. “In fact, many of these approaches are unsupported by good evidence and can sometimes make people feel worse, especially if they are very low in energy or protein. If you want to support your gut and overall health, the basics still matter most: regular meals, enough fibre, enough fluid, and a varied, nutrient-rich diet.”