Nutrition is one of the most talked-about – and often misunderstood – topics in health. With so much information circulating on social media, it’s easy to get caught up in myths that sound convincing but don’t hold up against the science. At Oracle Healthcare, we want to clear up some of the confusion. Let’s take a closer look at five common nutrition myths and what the evidence actually shows.
Myth 1: “Carbs make you gain weight.”
Carbs are often the first foods people cut when the number on the scale creeps up, but carbohydrates themselves don’t cause weight gain – it’s excess calories that matter. Our body weight is determined by the balance between the calories we consume and the calories we burn, so eating too much of any food, even healthy options, can lead to weight gain.
Gram for gram, carbs contain the same calories as protein and far fewer than fat. They’re also your body’s preferred fuel source – supporting everyday movement, exercise and brain function.
What does matter, is the amount and type of carbohydrates we eat. More refined and highly processed options like confectionery, pastries, white bread, chips and sugary drinks, contain less nutrients, digest quickly and are easy to overeat – which can push calorie intake higher.
In contrast, minimally processed, sources of carbohydrates such as whole grains, legumes, fruit, and starchy vegetables are higher in fibre and range of essential vitamins and minerals. They digest more slowly, helping keep blood sugar levels steady, and you feeling fuller for longer on fewer calories. Long term studies show limiting added sugar, refined grains, and starchy vegetables in favour of whole grains, fruit, and non-starchy vegetables may support efforts to control weight (Wan Y et al, 2023). They’re also linked to better gut health, improved cholesterol and a lower risk of chronic diseases including type 2 diabetes (Aune D et al., 2013).
Takeaway: You don’t need to cut out carbs to manage your weight. Choose mostly whole-food varieties, pair them with protein for better blood sugar control, and enjoy them in portions that suit your energy needs.
Myth 2: “Artificial sweeteners cause cancer.”
Claims linking artificial sweeteners to cancer regularly circulate online, but decades of research show that approved sweeteners are safe when consumed within recommended limits.
Sweeteners such as aspartame, sucralose and stevia have been extensively studied in both animals and humans. Reviews from authorities including Food Standards Australia New Zealand, the Joint FAO/WHO Expert Committee on Food Additives (JEFCA), World Cancer Research Fund have found have found no strong evidence of a direct link between sweeteners and cancer at usual intake levels.
In 2023, the International Agency for Research on Cancer (IARC) classified aspartame as possibly carcinogenic (Group 2B), based on limited evidence from human and animal studies involving very high intakes (WHO, 2023). Importantly, the JECFA reviewed the same data and did not change the Acceptable Daily Intake of 40mg/kg per day – equivalent to around 15 cans of diet soft drink a day for an average adult. Current data show that most Australians consume far less than this, staying well within safe limits (Australian Bureau of Statistics, 2023).
How sweeteners are used matters. Swapping sugar-sweetened drinks for diet options can help reduce added sugar, energy intake and support blood glucose management – but they’re not a health shortcut, and over-reliance on sweetened foods of any kind can displace more nutritious choices.
Takeaway: Artificial sweeteners do not cause cancer when consumed within recommended amounts. They can be a useful tool for reducing sugar, best used alongside a diet based on whole, minimally processed foods.
Myth 3: “Seed oils cause inflammation.”
Seed oils (like canola, sunflower, soybean and corn oil) are often blamed for inflammation, but evidence doesn’t support this claim.
The idea comes from the fact that seed oils contain omega-6 fats including linoleic acid, which can be involved in inflammatory pathways. However, high quality studies in humans show that a higher omega-6 intake does not increase inflammation (Bjermo H et al., 2012), (Su H et al., 2017). In fact, multiple trials and reviews find no rise in inflammatory markers when omega-6 fats replace saturated fats – and in some cases, inflammation markers improve (Drouin-Chartier JP et al., 2018).
Large reviews and expert bodies consistently conclude that linoleic acid (the main fat in seed oils) is neutral or beneficial for inflammation and is associated with lower LDL cholesterol and reduced heart disease risk, not worse health outcomes (Li J et al., 2020).
That said, seed oils are commonly used in ultra-processed foods like packaged snacks, takeaway foods and baked goods. Cutting back on these foods is a good idea – not because of the seed oils themselves, but because ultra-processed foods are often high in energy, refined carbs, salt and low in fibre and micronutrients. These dietary patterns, not seed oils alone, are more strongly linked to chronic inflammation and adverse health outcomes (Lane MM et al., 2024), (Aseni TM et al.,2023).
Takeaway: Seed oils don’t cause inflammation when eaten as part of a balanced diet. Reducing ultra-processed foods is sensible for overall health, while using seed oils at home to replace saturated fats is supported by high-quality evidence.
Myth 4: Frozen vegetables aren’t as nutritious as fresh ones
Many people believe that fresh vegetables are always nutritionally superior to frozen, but research doesn’t support that claim. Frozen vegetables are typically picked at peak ripeness and flash frozen soon after harvest, which helps lock in vitamins, minerals, and antioxidants that can degrade in fresh produce as it travels and sits on shelves. In some cases, frozen vegetables actually retain equal or greater nutrient levels than fresh vegetables that have been stored for several days before eating (Bouzari A. et al., 2015).
On top of nutrition, frozen vegetables can help reduce food waste, save money, and make it easier to always have a variety of vegetables on hand — perfect for quick meals without worrying about spoilage.
Takeaway: Frozen vegetables are a convenient, cost-effective, and nutritious choice that can help you eat more veg, even when fresh options aren’t available.
Myth 5: Fruit is too high in sugar and should be limited
It’s true that fruit contains natural sugar, but that sugar comes with fibre, vitamins, minerals and powerful antioxidants that support overall health and slow the absorption of sugar into your bloodstream, helping prevent large spikes in blood glucose. The soluble fibre abundant in many fruits, also helps improve blood cholesterol and supports gut health, which in turn reduces disease risk.
Large observational studies show that higher fruit intake is linked with lower risk of chronic diseases. For example, regular fruit consumption is associated with improved insulin sensitivity and a lower risk of developing type 2 diabetes, even when accounting for other lifestyle factors (Huaidong Du et al., 2017). Meta-analyses also find that diets high in fruit, vegetables and fibre are associated with reduced risk of cardiovascular disease and certain cancers (Aune D et al., 2017).
Takeaway: Unlike added sugars in processed foods, the naturally occurring sugar in whole fruit is packaged within a nutrient-rich matrix that promotes metabolic health rather than harm, supporting stable blood glucose and long-term well-being.
The Bottom Line
Nutrition doesn’t have to be confusing. Most myths come from kernels of truth that get twisted into extreme, black-and-white rules. Instead of looking for magic foods or quick fixes, focus on the basics that consistently support long-term health:
- Eat mostly whole and minimally processed foods
- Include a mix of protein, healthy fats and high-fibre carbs
- Enjoy fruit and vegetables daily
- Choose sustainable habits over trending ones
When you stick with simple, evidence-based nutrition, everything becomes much clearer and far less stressful. And if you’d like some personalised, evidence-based support to help you cut through the noise, our team of Accredited Practising Dietitians can support you to understand how food works for your body, build confidence around food choices, and feel informed and comfortable navigating nutrition.
Jess Burvill
BNutrDiet (Hons)(Dean’sSchol)
References
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Australian Bureau of Statistics. 2023. National Nutrition and Physical Activity Survey – Sweetened Beverages. Available at https://www.abs.gov.au/statistics/health/food-and-nutrition/sweetened-beverages/2023
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Drouin-Chartier JP, Tremblay AJ,Lépine MC, Valéry Lemelin, Lamarche B, Couture P. Substitution of dietary ω-6 polyunsaturated fatty acids for saturated fatty acids decreases LDL apolipoprotein B-100 production rate in men with dyslipidemia associated with insulin resistance: a randomized controlled trial. Am J Clin Nutr. 2018;107(1):26-34.
Du H, Li L, Bennett D, Guo Y, Turnbull I, Yang L, Bragg F, Bian Z, Chen Y, Chen J, Millwood IY, Sansome S, Ma L, Huang Y, Zhang N, Zheng X, Sun Q, Key TJ, Collins R, Peto R, Chen Z; China Kadoorie Biobank study. Fresh fruit consumption in relation to incident diabetes and diabetic vascular complications: A 7-y prospective study of 0.5 million Chinese adults. PLoS Med. 2017 Apr 11;14(4).
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