Attention deficit hyperactivity disorder diagnoses have risen in recent years. The NHS estimated that 2.5 million people in England had ADHD as of May 2025, intensifying debate about how the condition is diagnosed and understood.

Channel 4’s documentary The Great ADHD Myth? has added fresh fuel to that argument. Hosted by psychiatrist and Trust Me, I’m a (Junior) Doctor author Max Pemberton, the investigation argues that ADHD is diagnosed and medicalised too frequently.

The programme has faced significant backlash. The Guardian television critic Lucy Mangan called it “the most controversial show of the year” and wrote that its scepticism about ADHD was apparent from the beginning.

ADHD UK also issued a strongly critical response. The charity wrote: “We watched. We said we’d be fair. Here is our verdict. ADHD is not a myth. It is not a social construct… We have already complained to Ofcom. A fuller submission follows, built on the impact data you give us below.”

Beyond the disputes surrounding diagnosis and medication, the documentary raises another question: Can everyday habits, including diet, influence how severely ADHD symptoms appear? Sugar is an obvious focus because of its long association with hyperactivity.

Neurophysiological psychologist Sarah Warley, founder of The Key Clinic and a contributor to the documentary, says sugar does not cause ADHD or anxiety. However, she believes “it can fuel the symptoms of both, including in those without a diagnosis”.

“Riding a roller coaster of blood sugar spikes and crashes affects energy, mood, concentration and emotional regulation,” Warley says. She argues that these fluctuations may intensify existing symptoms or be mistaken for ADHD symptoms.

Warley says that when blood sugar falls quickly after a spike, the body releases cortisol and adrenaline. She describes these as the same stress hormones involved in anxiety, irritability and the fight or flight response.

“For adults or children with ADHD, this blood sugar instability can look like restlessness, anger, inability to concentrate, emotional meltdowns and fatigue. These symptoms are then attributed to the ADHD itself rather than to what was eaten for breakfast,” she says.

Scientific evidence connecting diet with ADHD remains limited and is still developing. A 2014 Korean study found that children with ADHD were more likely to follow a dietary pattern containing high amounts of snacks and processed meat, but it identified an association rather than causation.

A larger 2019 study followed almost 3,000 children between six and 11 years old. Researchers found no association between consistently high sugar consumption and developing ADHD during that period.

Those researchers suggested that higher sugar consumption could sometimes result from ADHD rather than cause it. Children with the condition, for example, may gravitate toward quick sources of energy.

Warley also points to a review proposing that chronic high sugar intake could blunt dopamine signalling in ways that contribute to ADHD symptoms. Its authors presented that possibility as a hypothesis requiring further research, not as an established finding.

There is no evidence based ADHD diet, and reducing sugar is not a recognised treatment for the condition. Dietary changes should not replace prescribed medication or professional support, and anyone considering changing or stopping ADHD medication should first speak with a doctor.

Warley advises against extreme dietary changes or highly restrictive plans. Instead, she recommends eating a nutritionally varied diet and adding manageable sources of variety, such as berries with porridge, red pepper sticks at lunch or broccoli with dinner.

When addressing sugar specifically, Warley recommends reducing how frequently it is consumed rather than banning it completely. She says gradually cutting back may also lead taste buds to perceive foods with less sugar as sweet.

Eating chocolate biscuits does not cause ADHD, and replacing cereal with eggs will not cure it. Sleep, stress, emotional wellbeing and meal timing can also play roles in how symptoms present, according to the article.

The practical advice is straightforward: eat regularly, increase dietary variety, reduce added sugar where possible and continue taking prescribed medication unless a doctor advises otherwise. Sugar is not the cause of ADHD, and no single diet can treat the condition.