The 3 Most Risky Diet Trends — and Why They Can Undermine Health

There is no shortage of diet trends promising better health, more energy or a “reset” for the body. Many start with good intentions — people want to feel well, regain control, or support their long-term health. But some popular approaches carry hidden risks, particularly when they encourage rigidity, restriction or fear around food.

As a dietitian, I don’t believe nutrition should be about extremes. Sustainable health is built on consistency, flexibility and nourishment — not punishment. Below are three diet trends that I see most commonly causing problems in practice, and why they deserve a more cautious approach.

1. “Clean Eating”

“Clean eating” often begins with positive aims: choosing whole foods, reducing ultra-processed products, and trying to eat in a way that feels supportive of health. On its own, that can be helpful.

The risk appears when healthy eating becomes rigid, rule-bound and anxiety-driven. For some people, the pursuit of eating “perfectly” slowly starts to dominate daily life. Food choices become stressful rather than nourishing, and enjoyment is replaced by constant monitoring and self-judgement.

This pattern is often referred to as orthorexic eating. While orthorexia is not formally recognised as a clinical eating disorder, it is increasingly acknowledged by health professionals as a harmful pattern of behaviour where the desire to eat healthily begins to damage physical, mental and social wellbeing.

Warning signs can include:

• Cutting out entire food groups without medical need

• Avoiding social situations because food cannot be “controlled”

• Spending excessive time thinking about ingredients or food “rules”

• Feeling guilt or shame after eating foods perceived as “unhealthy”

  
  

Over time, these patterns can lead to nutritional insufficiencies, low energy availability, hormone disruption and heightened stress around food. Ironically, extreme clean eating can undermine the very health it aims to protect.

A more sustainable approach to nutrition prioritises flexibility over perfection. This means including all food groups unless there is a clear medical reason not to, responding to hunger and fullness cues, and allowing room for meals that are both nourishing and enjoyable. Food is not just fuel — it is also connection, culture and pleasure, and those elements matter for health too.

2. “Detoxing” and Cleanses

“Detoxing” remains one of the most persistent wellness trends, often marketed as a way to remove toxins, reset the body or boost health. In reality, the body already has an extremely effective detoxification system. The liver, kidneys, lungs, digestive system and skin work continuously to break down and eliminate waste products.

There is no good scientific evidence that juice cleanses, detox teas or restrictive detox plans enhance this process. Yet these approaches remain popular because they promise quick results, control and clear rules — particularly after periods of indulgence or during times of stress.

The concern arises when detox diets replace balanced eating with plans that are very low in calories, protein and essential nutrients. Juice cleanses and liquid-only detoxes can lead to dizziness, fatigue, blood sugar crashes and weakened immunity within days. Detox teas and powders often contain laxatives or diuretics, causing rapid fluid loss that is mistaken for weight loss and increasing the risk of dehydration and electrolyte imbalance.

The language of detoxing also creates fear. It suggests that the body is full of dangerous “toxins” that need to be flushed out — yet most people cannot identify what toxin they believe they are removing. In practice, people are usually responding to feeling “off”: too much alcohol, irregular eating, highly processed foods, poor sleep or high stress.

The paradox is that extreme detoxing can impair health rather than restore it. With inadequate energy and protein intake, the body begins to break down muscle tissue, energy levels fall, concentration suffers and hormone balance can be affected. The immune system also depends on adequate nutrition — meaning detoxing can leave people more vulnerable at the very moment they are trying to feel healthier.

Psychologically, detoxing often reinforces an unhelpful cycle of “good” and “bad” eating. This pattern is strongly linked to binge–restrict behaviour, shame around food and long-term weight cycling, all of which are associated with poorer health outcomes.

A gentler and far more effective “reset” is simply returning to regular, nourishing meals that include protein, fibre, colourful plant foods and adequate hydration — alongside sleep, movement and stress management. The body does not need punishment to recover; it needs support.

3. Fasting and Extreme Time-Restricted Eating

Intermittent fasting is often promoted as a way to improve metabolic health, reduce inflammation or support weight loss. While short fasting windows may suit some individuals, the risks are frequently overlooked — particularly when fasting becomes rigid or extreme.

Many people adopt fasting without considering their own physiology, lifestyle or medical history. Skipping meals or compressing intake into a narrow eating window can lead to under-fueling, especially in women, people with high stress levels, active individuals or those with a history of disordered eating.

Common consequences I see in practice include:

• Low energy and poor concentration

• Blood sugar instability, irritability and headaches

• Disrupted sleep

• Digestive symptoms such as bloating or constipation

• Increased preoccupation with food

  
  

For some, fasting triggers a cycle of restriction followed by overeating later in the day, reinforcing guilt and loss of control around food. For others, it suppresses appetite signals and masks inadequate intake until symptoms appear.

Fasting is also not neutral from a hormonal perspective. Chronic under-fueling can affect menstrual health, thyroid function and stress hormones, particularly when combined with exercise or poor sleep. These effects are often missed because they develop gradually rather than immediately.

Nutrition works best when the body feels safe and consistently fuelled. Regular meals help regulate appetite hormones, support gut function, stabilise blood sugar and provide the nutrients needed for daily life. For many people, eating consistently — rather than eating less often — is the more protective and sustainable option.

The Bigger Picture

Many diet trends are appealing because they offer certainty in a confusing nutrition landscape. They promise clarity, control and quick fixes. But health rarely comes from extremes.

The common thread linking risky diet trends is not a specific food or timing pattern — it is rigidity, fear and chronic restriction. When eating becomes something to manage perfectly rather than a way to care for the body, both physical and mental health can suffer.

A healthier approach to nutrition is grounded in balance, flexibility and compassion. It allows room for nourishment and enjoyment, adapts to real life, and supports health without creating stress or guilt around food.

Because nutrition is not about doing it “right” — it’s about supporting your body, consistently and kindly, over time.