‘I feel completely powerless,’ the man told me. ‘Heroin is ruining my life.’
This man was my first patient when I became a psychologist 15 years ago, specialising in the field of addiction.
I’ll never forget him because, as he spoke to me about the power his addiction held over his life, I realised with a jolt that his story reflected my own.
My addiction wasn’t to drugs, however. I was addicted to dieting.
And as he spoke, I realised that this man – and, after him, countless other patients who shared honest details of their powerlessness with alcohol, gambling and many other habits – reflected my own relationship with food back to me far better than any therapist or doctor ever could.
All those patients described feeling short–changed by substance abuse, just as I felt utterly short-changed by my then-decades of dieting, which had only left me miserable, at war with my own body.
From my teenage years, I had tried every diet going – to no avail. At my heaviest, at 5ft 7in aged 21, I was almost 19st – both the fattest person and the most compulsive dieter around.
This was because, just as every high had left my patients more addicted to their vice, each of my own failed diets had only given me a stronger addiction to every aspect of the weight-loss cycle: the ‘highs’ for me were the sense of control that restrictive eating brought – and the release of the binge that would inevitably follow the diet’s failure.
Shahroo Izadi in her 20s – after a failed gastric–band operation and years of diets followed by heavy bingeing
I had been trained to support society’s most change-resistant and highly addicted people. It was a revelation to realise my own behaviour was driven by similar emotional and biological – behaviours.
For alongside the psychological pendulum of the highs (‘I’ll be so happy when I lose the weight’) and lows (the inevitable breaking point of a diet), the cycle of dieting and bingeing triggers a flood of chemicals in your brain that over time become entrenched – making each subsequent attempt at control more likely to fail.
And the diet industry actually wants you to fail – it needs you to feel broken, powerless and dependent on its solutions.
Because if you believed you could trust yourself around food, you’d stop buying diet products, joining weight–loss programmes and listening to the endless conflicting advice that keeps the industry profitable. But more on that later.
After six years of working with NHS patients, I moved into private practice – helping people who suffered from substance misuse and running workshops for health workers on how to empower addicts to change for good.
But given my personal experience, one addiction fascinated me more than any other: dieting. It seemed everywhere I looked, I could see people like myself, quietly imprisoned in its cycle and who simply couldn’t conceive of a life without being on a diet – despite how ineffective their eating plans proved in the long term.
I’ve heard tearful confessions of global leaders of industry who manage complex careers, but can’t control themselves around a doughnut.
The reality is that smart, disciplined people can also be diet addicts, trapped in cycles of restrictive eating and wild food binges.
Indeed, this was my life until my late 20s. I remember first feeling dissatisfied with my shape aged ten, when other children would make fun of my size, and my family – concerned about my weight – encouraged me to eat less and avoid ‘naughty’ foods.
As a teenager, I began taking appetite suppressants (bought online via pro–anorexia forums) and embraced absurdly restrictive diets: boiled eggs and cabbage soup; only celery; or just meat. I lost weight, but it was obviously unsustainable and I’d end up bingeing.
Those binges taught me eating large quantities of fatty, sugary foods was exhilarating, euphoric – even emotionally numbing. I’d restrict for days, then see a photo and feel hopeless. That combined with hunger made me cancel plans and spend entire weekends eating to physical discomfort.
After every binge, though, came shame… and I would start a new diet.
It was very similar to the trajectory of substance abuse. The more I dieted, the less effective those diets became.
In turn, I started needing a higher ‘dose’ of my drug, if you will, just as a drug addict might – in my case, this took the form of making my diets even more restrictive to shift any weight at all, almost starving myself between binges.
As my diets became more intense, my binges became more extreme, too – so much so the skin on my stomach and thighs would itch (I looked up what this was, and discovered it was actually the formation of stretch marks – the skin stretching and tearing in real time).
Then, in my second year of university, aged 21, I had gastric–band surgery paid for privately. Ashamed, I kept it secret.
Initially, I was able to eat as much as I had always done after the surgery – because the band had been installed around my upper stomach and was loose enough that I wouldn’t feel it.
Once I’d recovered from the operation, I could return to get it tightened.
At first, in that pre-tightening stage, I ate almost nothing. Then, predictably, I ate everything ‘one last time’. After all, I no longer needed to rely on myself to get thin – I had the band.
When it was tightened, I lost weight quickly – so I kept asking the surgeon to tighten it as much as possible, essentially using it to starve myself. I went from a size 22/24 to a size 6 at my smallest, in about a year or so.
For the first time, I was very slim, around 52kg (8st 2lb). But old habits die hard. I was in and out of the clinic for 18 months, asking for extreme loosening or tightening, and playing out my restriction-rebellion pattern of crash dieting – only this time with a surgical intervention.
But despite the band, I found ways to continue bingeing – soft, high-calorie foods I could get down, even when my stomach felt very tight. Eventually, the pain became unbearable and I was operated on again.
The surgeon explained he’d had to remove the band because it had slipped from its original position (a recognised complication, which can be linked to overeating).
I was 26 and had been struggling with the band for years – by then I weighed around 90kg (around 14st 2lb) again. I cried, knowing I’d hit rock bottom.
I then went to therapy, a habit I would keep for the next decade. Eventually, it helped me think about my problem objectively and have compassion for myself, the way I would for anyone else. Like I would for any addict, as I now see it.
Ms Izadi today… she says she is living proof that anyone can conquer addiction
Encouraged by my therapist, I resolved to act as if I’d never lose weight. Before that point, I wouldn’t wear make-up when overweight, do my hair or even light a candle at home – nice things were for thin people, after all.
But now I was to treat my body kindly.
Eventually, I noticed I felt more deserving, and found myself losing weight and not gaining it back – simply because I wasn’t eating uncontrollably. Then I had my eureka moment with my heroin-addicted patient.
I had already been trained in managing addictions by teaching patients simple techniques that help build their confidence to confront their addiction and break their habit.
I began to use these techniques myself – for example, one of the most powerful was to repeatedly say to myself as I fell into another binge: ‘These hands are my hands’. It reinforced that I wasn’t powerless. This technique is about preventing that experience from reinforcing the powerlessness that fuels addiction. In my case, it helped break the cycle of frantic over-consumption and restriction.
By treating my struggle with the compassion I would give an addict struggling to stick to their programme, I lost 8st in 18 months. I had finally learned to manage my addiction to dieting.
Once I realised the overlap between my dysfunctional behaviour and other addictions I was treating as a medical professional, I began to research the exact biological and psychological mechanisms by which dieting addiction works.
As I’ve mentioned, diets create a psychological pendulum, where the ‘high’ of perfect restriction swings inevitably to the ‘low’ release of complete abandon – setting up a psychological dynamic where the eventual breakdown feels like both failure and release.
This is because the restriction phase increases stress hormones such as cortisol (because restricting food is stressful!), while simultaneously creating the psychological anticipation of future reward (joy on losing weight). It’s a psychologically intoxicating, dangerous mix.
Then the inevitable breaking point of a diet triggers a flood of relief chemicals in your brain – dopamine, serotonin, endorphins – as you finally eat forbidden foods.
This relief is immediately followed by intense shame, creating another cortisol spike that drives the need for more relief. You return to restriction as the only way to escape the shame of failure, beginning the cycle again.
The more times you cycle through diets, the deeper these psychological pathways become entrenched. Your attachment to dieting isn’t logical – it’s biochemical.
Indeed, research published in Obesity Reviews in 2015 shows just how repeated dieting only succeeds in heightening your body’s response. Scientists found each cycle of weight loss and regain progressively amplifies both metabolic changes and psychological drive that lead you to overeat.
When I treated dieting like addiction recovery – gradually changing my habits, one step at a time, so eventually I was eating regularly, which prevented my body unleashing those biological responses which had fuelled my diet addiction, and so changed my entire mindset – the brain chemistry normalised. This took more than 18 months, and I lost 8st (I’ve maintained stable weight since 2013).
But aside from this mental impact, what else makes diets doomed to fail – yet simultaneously addictive?
Diets also disrupt your body’s hormone levels and other regulatory systems.
When you restrict food severely, even for short periods, your body can enter a state of perceived famine. It doesn’t understand concepts like ‘diet’ or ‘bikini body’. It simply registers a dangerous shortage of incoming energy and triggers a cascade of biological changes to protect you from potential starvation.
This is because your body has a setpoint weight – a particular pre-determined weight range. Everyone’s is naturally different – but the further below it you go, the more aggressively your body fights to preserve it, and the sooner your diet will fail.
Indeed, when you diet, your body reduces production of hormones that signal fullness – such as leptin, GLP–1 (the hormone used in weight-loss jabs such as Wegovy) and peptide YY – which in turn increases your appetite.
Significantly, a 2011 study by the University of Melbourne tracked 50 dieters across 12 months and showed these hormonal adaptations persist long after weight loss, creating sustained biological pressure towards weight regain.
In short, dieting makes you hungrier, even after you have finished dieting.
Diets also decrease your metabolism (the rate you burn calories) as your body slows down energy expenditure because it perceives a potential famine ahead.
This perceived famine also affects the dieter’s brain, causing an urgent ‘eat now while you can’ mindset as soon as food becomes available.
It’s not gluttony or lack of discipline – rather a deep-rooted survival instinct, as your brain responds with appropriate urgency. Hence the frantic nature of binges that occur after diets: eating while standing up; barely chewing; and sometimes not even tasting the food.
Diets also change how your brain responds to food, making your reward centres more sensitive to it. Research by Columbia University in 2008 used MRI scans and found that, after weight loss, brain regions associated with reward lit up more intensely when shown food images.
This means that what would give a normal eater a mild pleasure response instead hits with the force of an overwhelming compulsion.
That first bite triggers dopamine release – a feelgood chemical in the brain involved in reward and motivation.
Years of restriction-binge cycles make a dieter’s brain hypersensitive to this response. That’s why that first bite triggers such a powerful drive to keep eating. I’ve watched this in hundreds of clients.
Perhaps the most fascinating thing is what happens to a dieter’s executive function, the part of the brain involved in rational decision making.
Diets force one’s executive function to be temporarily overridden by the urgent need to survive the perceived famine. Yale University research in 2011 showed food restriction reduces activity in the prefrontal cortex – home of the brain’s executive function – while increasing activity in regions associated with reward-seeking. No amount of willpower can overcome this urge to eat. It’s like trying to think your way out of a sneeze.
Long periods of food restriction also wear down mental energy, a well-documented phenomenon known as cognitive depletion, which affects everyone under conditions of prolonged self-discipline, making impulse control much harder.
Put simply then, diets are toxic for your body and mind.
And the ultimate goal of any abusive relationship is to create ‘learned helplessness’, a psychological state where victims stop believing escape is possible.
Like an abusive partner, diets create this state of mind through repeated experiences of failure.
The diet industry is set up to profit from the lucrative cycle of failing, says Ms Izadi
Even when you’ve experienced a diet’s failure first-hand dozens of times, this state of learned helplessness keeps you trapped in the cycle. I’ve seen people for whom dieting has become so fused with their identity that they don’t know who they would be without it. For these people, stopping dieting prompts a form of grief.
So why isn’t dieting commonly viewed as an addiction?
I believe it remains largely undiagnosed because it falls through the cracks of existing clinical guidelines.
There are large overlaps with eating disorders, most obviously with binge-eating disorder (BED), where sufferers have recurring episodes of eating large quantities of food rapidly to the point of discomfort, accompanied by feelings of guilt or distress.
Diet addicts can be mislabelled as suffering from BED – but this is different from BED, because it has a large component of compulsive restriction to it.
There’s also obvious overlap between dieting addiction and anorexia – and also with bulimia’s binge-eating episodes.
At heart, I believe this psychological problem is caused by the modern diet industry.
After all, it is the diet industry – whether via meal-replacement shakes, calorie-counting plans or unbalanced protein-heavy diets such as Atkins and keto – which encourages us to attempt weight loss using quick-fix approaches that trigger biological starvation responses.
Then the vast majority of dieters regain weight. But this failure – and state of learned helplessness it inflicts – only means you’ll chase another diet again, buying books, products and downloading apps, boosting the industry’s profits.
It profits from your shame of failing, in what is a perniciously lucrative cycle for them.
But you can conquer your addiction to its product – and rediscover your natural instincts around food. I’m living proof.
Why fat jabs aren’t the answer…
My clinical work has shown me recovery from dieting and disordered eating requires you to develop an unshakeable self-trust around food. To know you can control yourself, on your own.
This is why so many popular weight–loss tactics don’t work.
Take fat jabs – they portray food as the enemy and your powers of self-control as requiring external assistance. The same goes for fat camps, gastric bands and appetite suppressants.
Pre-prepared meals that arrive at your door are also another crutch.
The only route forwards is to painstakingly reform the habits that cause your overeating.
Adapted from How Diets Make Us Fat by Shahroo Izadi (Leap, £20). © Shahroo Izadi 2025. To order a copy for £18 (Offer valid to 27/12/25; UK P&P free on orders over £25) go to mailshop.co.uk/books or call 020 3176 2937.