Health Update: 10 common food myths debunked – What Experts Say

Every January, the same food fears resurface. One-week carbohydrates are blamed for weight gain. The next, it is seed oils, gluten, or eating after 6pm. Scroll for long enough and it can feel as though everything in your kitchen is working against you.

The reality is far less dramatic. Most of these claims are recycled myths, repackaged as new discoveries. They spread quickly because they are simple, extreme, and confident. What they are not is strongly supported by evidence.

According to nutritionist Laura Kealey, following restrictive diets or online nutrition trends can be damaging.

“The main harm is that constant restriction often leads to an unhealthy relationship with food and a cycle of “on/off” dieting, rather than sustainable habits,” she told Breaking News.ie.

“Many trends cut out whole food groups or set unrealistic rules, which can increase stress, guilt and overeating later.

“Over time, it can also reduce overall nutrient intake (like fibre, vitamin C iron, and calcium), impacting energy, digestion, mood and long-term health.”

Here are some of the biggest nutrition myths people continue to fall for, and what the science actually shows.

Myth 1: Carbohydrates cause weight gain

Carbohydrates are often blamed for weight gain, yet weight change is driven by overall energy intake over time, not by one food group.

According to guidance from Food Safety Authority Ireland (FSAI), carbohydrates are the body’s primary source of energy and play a key role in brain function, daily activity, and exercise performance. Research consistently shows that very low-carbohydrate diets are associated with fatigue, low mood, and increased cravings, particularly when followed long-term.

Foods such as potatoes, rice, fruit, and wholegrains are all carbohydrate sources and provide fibre and essential nutrients that many people do not consume enough of.

Myth 2: You need to supplement with protein powder to hit daily targets

Most people do not need shelves full of supplements.

Research summarised by FSAI shows that protein intake is commonly low at breakfast and snack times, despite protein’s role in muscle health, bone health, recovery, and appetite regulation. Higher-protein diets have been shown to support satiety and help people feel fuller for longer. High-protein foods such as yoghurt, skyr, and kvarg offer a simple way to close this gap. Lindahls kvarg products are one practical example, providing high protein with low fat and added sugar, making them easy to include as a snack or dessert.

Supplements should support a balanced diet, not replace it.

Myth 3: Intermittent fasting is the best way to lose weight

Intermittent fasting is often sold as the best and fastest way to lose weight, but it is not automatically better than any other approach.

Research shows it can work for some people, mainly because it helps them reduce overall calorie intake, not because it “switches on” fat burning. For others, it can backfire, leading to low energy, strong cravings, and overeating later in the day. It can also be a poor fit for anyone training regularly, as long gaps without food can affect performance, recovery, and mood. The most effective plan is the one you can stick to consistently, and the HSE highlights that steady, balanced habits are what support long-term weight management.

Myth 4: Greens powders replace fruit and vegetables

Greens powders are often marketed as a shortcut to good health. However, evidence shows that fibre from whole fruit and vegetables plays a crucial role in digestion, gut health, and blood sugar control. Most greens powders contain little to no fibre and cannot replicate these benefits.

Myth 5: Everyone should go gluten free

A gluten-free diet is essential for people with coeliac disease. For everyone else, it isn’t necessary. According to the HSE, removing gluten without medical need often reduces wholegrain intake. Wholegrains are consistently linked with better heart health, gut health, and fibre intake. Many gluten-free alternatives are lower in fibre and higher in added sugar.

Unless medically advised, there is no need to avoid gluten.

Myth 6: The carnivore diet is healthy long-term

The carnivore diet excludes all plant foods, including fruit, vegetables, and grains.

Dietetic bodies, including the INDI, note that while short-term weight loss can occur, it is largely due to reduced calorie intake and water loss. Over time, the diet lacks fibre and several essential micronutrients, with potential risks to gut and cardiovascular health. There is no strong evidence supporting this approach for long-term health.

Myth 7: Detoxes and juice cleanses remove toxins

Detox products and juice cleanses claim to flush toxins from the body. Medical evidence reviewed by the INDI shows no benefit of detox diets for toxin removal, as this process is already carried out efficiently by the liver and kidneys. Studies consistently report that detox diets are associated with low energy, headaches, and rebound overeating.

Regular meals, adequate protein, fibre, and fluids are far more effective for health.

Myth 8: Eating after 6pm causes weight gain

The time on the clock does not cause weight gain, total intake over the day does. Evidence shows that overall daily intake, rather than meal timing alone, is the main driver of weight change. Many people train or work late, and rigid cut-off times can lead to under-eating earlier and overeating later. Meal timing should suit lifestyle, not strict rules.

Myth 9: Seed oils are toxic

Sunflower, rapeseed, and other vegetable oils have recently been blamed for inflammation, weight gain, and poor health.

However, evidence based guidance from the FSAI states that replacing saturated fats, such as butter or lard, with unsaturated fats consistently lowers the risk of heart disease. Large population studies examining dietary fat intake show lower rates of cardiovascular disease when unsaturated fats are consumed in place of saturated fats.

Like all fats, seed oils should not be overheated or reused repeatedly, but the current fear around them is driven by online trends rather than research.

Myth 10: Ultra-processed foods must be avoided completely

Not all processed foods are the same. Bread, yoghurt, and fortified cereals are processed foods that still contribute important nutrients. Research examining dietary patterns shows that health outcomes are shaped by overall diet quality rather than the inclusion or exclusion of individual foods. An all-or-nothing approach often increases food anxiety and reduces long-term adherence. A mostly whole-food diet, with room for convenience and enjoyment, is more realistic and sustainable.

The bottom line

Nutrition does not need to be extreme. Most myths fall apart once evidence replaces headlines. Eating regular, nutrient-dense meals and snacks prioritising protein, fruit, vegetables, and fibre, and choosing habits that fit real life will always beat strict rules. You do not need to detox, fear food, or chase every new trend.

You simply need less noise and more common sense.

So, what simple changes can you make? Laura Kealey has a parting word of advice: “The biggest difference comes from simple, consistent habits.

“Regular meals and snacks, plenty of fruit and veg, enough protein, and high-fibre foods like wholegrains, beans and lentils.

“Keeping ultra-processed foods and sugary drinks as “sometimes” rather than daily, staying hydrated, and being active most days also matters.

“Add in good sleep and stress management, and you’ve covered the real foundations of lifelong health.”