Like so many women, I binged and starved my way through the first part of my adult life, repeatedly losing, then gaining the same 14lb, but in 2010 I set myself a New Year’s resolution – to go an entire year without dieting, to stop weighing myself and to exercise every day instead – either enjoying a long walk or taking a dance class.

My work as a Yale University neuroscientist had convinced me my brain had been struggling to deal with the pattern of yo-yo dieting I’d followed since my teens, and I was keen to set myself up as a guinea pig to see if healthy eating could achieve the same results.

In fact, it was better. Within weeks, my body had settled on a healthy stable weight which I’ve happily maintained – no dieting! – ever since.

Yale University neuroscientist Sandra Aamodt was convinced her brain had been struggling with a pattern of yo-yo dieting since her teens

If you’ve ever stuck rigidly to a diet, managed to lose weight but then piled the pounds back on, I can reassure you, it’s not your fault.

The chances are you’re not lazy, greedy or woefully lacking in will-power – after about five years, 41 per cent of dieters gain back more weight than they’d lost – it’s just that your brain takes charge, doing what it has evolved to do: fighting back against the perils of potential imminent starvation.

The truth is, everyone’s brain has a set body weight range that it will fiercely defend. No matter what the number is on your scales, there’s very likely to be a set point at which you are stuck. The range, which varies from person to person, is determined by genes and life experience.

In an ideal world, your brain defends this range with a natural process of subconscious weight regulation which gently nudges hunger and activity levels so you eat or exercise no more or less than your body needs.

Your ‘brain weight’ spans about a stone, and within this range your weight will be relatively easy to manage.

She was keen to set herself up as a guinea pig to try healthy eating instead of yo yo dieting -and within weeks her body had settled to a normal weight 

But, as every inveterate dieter knows, dropping too low may let you squeeze into your skinny jeans, but it will be fiendishly difficult to maintain. There’s every chance if you drop below your brain weight, you’ll meet powerful resistance in the form of cravings for quick-fix calories and energy-conserving listlessness.

You’d think these natural ‘starvation!’ alerts would kick in only once your ribs started showing, or a thigh-gap appeared, but infuriatingly, everyone’s brain weight is different.

If you’ve gained pounds over the years, with successive diets resulting in an expanding waistline, your brain weight is likely to have settled at a level far higher than the dream weight you so long to return to.

This means your brain could regard a drop even to the point of last year’s lowest level as threateningly low, and resist your attempts to get there.

If you have a tendency to binge-eat or nibble even when you’re not hungry, there’s every chance your brain weight is higher than it should be. If you are always hungry and cold, there’s every chance you are below it.

The good news is that if pregnancy, illness or a long, gluttonous holiday cause a dramatic hike out of your zone (more than a stone), if you act within 12 months you should be able to re-establish your brain weight at the lower level it was at before.

However, if you don’t act quickly to bring your weight back down, there’s every risk your brain will take this new higher weight as your new normal.

But, although hard, you can bring your brain weight down.

The best way to discover your true brain weight is to make the conscious decision to stop dieting and try ‘intuitive eating’

It is simple: eat only when you’re hungry and stop when you’re full. Within six to 12 months, your weight should stabilise to your brain’s desired range.


Under most conditions, your brain’s energy-balance system should be highly effective, achieving 99.5 per cent accuracy in matching the calories in versus calories out equation. But its function is strongly challenged by the natural reward system.

For our ancestors, killing a large animal or finding a nest full of honey was a rare and wonderful event, so it made sense to over-eat at those moments and store as many calories as possible for the lean times that might come later.

But in the modern world, tempting food is everywhere.

Junk food mucks about with the delicate balance of gut bacteria which, studies show, can have an additional impact on whether you gain or lose weight

The food industry is constantly trying to manipulate your brain’s energy-balance system because profit margins depend on persuading us to eat more than we want or need. Numerous studies point at evidence that the typical Western diet of processed meat, sugar, white flour with few fruit and vegetables or wholegrains causes weight gain, and so raises your brain weight.

Junk food also mucks about with the delicate balance of gut bacteria which, studies show, can have an additional impact on whether you gain or lose weight.

Some gut bacteria work to help us get more energy from food (which can lead to obesity), while other gut bacteria work to modify signals of hunger and fullness.

Furthermore, the additives in processed food are thought to change the delicate balance of bacteria in our gut and the emulsifiers routinely added to many foods can disrupt the mucus barrier that lines the intestine, leading to inflammation, over-eating and weight gain.

I am convinced that dieting – which teaches us to ignore our body’s signals of hunger, leading most people to overeat when the opportunity arises – can make things worse. And all too often, dieting pitches food as a battleground and exercise as a punishment, which is definitely not a recipe for healthy eating.

My investigations have shown that dieting often makes people fatter and less healthy in the long run because it impairs their ability to recognise hunger, which increases vulnerability to emotional eating and the lures of clever food marketing.


The key to keeping your brain weight from creeping ever higher is adopting a few healthy habits.

When I started my year of non-dieting, I tracked everything I ate and the results were illuminating. I was sticking to one plan: eat when hungry and stop when full.

And every day it turned out my calorie intake was different. It varied from 1,400 some days to 2,400 on others, averaging 1,800 per day.

I noticed that the days when I ate a lot were typically followed by two or three days when I was less hungry and ate less. My brain, it seems, was much better at keeping track of my calorie intake than my dieting regimes had ever been.

I’m now very tuned into my brain’s signals and let my internal cues do the work. It’s intuitive eating and it really works. But I do help my brain get it right by following these steps:


Rigid food rules can lead to binges when they’re violated. It is so easy to think: ‘Oh well, I’ve blown the diet with that slice of birthday cake, I might as well eat the whole lot.’

In any case, few foods are as demonic or angelic as we make them out to be. If you’re stranded on a desert island, you’d live a lot longer on hot dogs than on spinach.

So instead of trying to keep up with the latest ‘carbs are in’ or ‘kale is out’ diet rules, try ‘intuitive eating’ whereby you eat whatever you want, but only when you’re hungry and stop eating as soon as you feel full.

If you’ve been on more than a few diets, there’s every chance you’ve spent too much time suppressing and ignoring hunger signals, and you could be less responsive to the signals that tell you to stop eating when you’re full.

However, by being ‘mindful’ of your cravings, urges, hunger pangs and food choices, you can re-condition your sensors and allow your brain’s natural energy-balance system to take back control.

It may take time (it took me a year), but we need to teach ourselves to eat in a way that’s relaxed and satisfying so that our weight can stabilise within the range that the brain defends.


Expand your dietary horizons. You give your brain the best possible chance to lower your weight if you eat more vegetables (five to 13 servings a day, or half the food on your plate), minimise added sugars, refined grains and processed foods and cook from scratch whenever you can.

The brain’s energy-balance system can deal much more accurately with the food you prepare yourself than it can with packets and tins, making it much more likely you’ll eat when you’re hungry and stop when you’re full.


You might not be able to outrun a bad diet (it’ll take 30 minutes of swimming to burn off a single glass of white wine), but a modest amount of exercise is key to getting your brain weight down

You might not be able to outrun a bad diet (it’ll take 30 minutes of swimming to burn off a single glass of white wine), but a modest amount of exercise is key to getting your brain weight down.

As well as burning calories, being active boosts metabolism, which also burns calories, and builds muscle, which in turn burns more calories.

It also eases stress and insomnia – both of which affect the hormones that cause weight gain – and regular activity reduces levels of harmful stomach fat.

Ability doesn’t matter as much as interest, sticking with it and slow improvement. So find something fun (even if you just walk around the block, chatting on your mobile phone at lunchtimes) and do it regularly.


Few of us realise that we make as many as 200-300 food-related decisions a day, most of them habitual (a muffin with your morning coffee, peanuts with that evening glass of wine, bread if it’s offered, a dessert when you’re out).

Barely noticed eating habits can easily override your brain’s conscious intentions and bamboozle its delicate ‘energy in versus energy out’ balance.

Intuitive eating should help you to highlight the bad food habits that might have crept into your life, and some – once you are aware of them – you might be able to easily drop.

The best way to ditch a stubborn bad habit is to replace it with a better one. For example, buy exotic herbal tea bags and use that ‘ah, the kids are in bed, it’s me-time now’ cue to boil the kettle rather than reach for the wine, and ask for olives instead of bread when you’re dining out.

But be warned – to make the change stick, a new habit must be repeated until it’s as strong as the old habit, which may be a lot of times if the old habit is deeply ingrained. Repetition is key. Studies show it can take 18 to 254 days (with an average of 66 days) for a new habit to stick.

One tip is to start a new habit during a low-stress time in your life. A relaxed brain has more mental capacity, which improves the odds of success.

Extracted by Louise Atkinson from Why Diets Make Us Fat: The Unintended Consequences Of Our Obsession With Weight Loss, by Sandra Aamodt, published by Scribe on September 15 at £12.99. © Sandra Aamodt 2016. To order a copy at £9.74 (offer valid until September 19), call 0844 571 0640 or visit PP free on orders over £15.