How to retrain your brain so you actually prefer healthy food

Neuroscientist Dr Jack Lewis says it IS possible

Woman chopping fruit in kitchen
Trinette ReedGetty Images

Before we start talking about healthy eating, we need to start at the beginning, and discuss how the brain actually works:

Our food preferences are hard wired

Did you know that the intensity with which the reward pathways in our brains fire when we see or smell of food was set in stone tens of thousands of years ago? Those pathways were developed so human beings naturally favoured foods that were high in energy, as this was fundamental to our ancestors' survival.

Back in the Stone Age, if there was a high sugar or high fat option available, choosing this meant there was a better chance of long-term survival. And while we've evolved in many ways compared to our cavemen predecessors, our brains have not followed as quickly. Essentially, our brains are still wired to prefer the foods that provide the most energy – high in sugar and fat. The things we don't need as much of in our modern sedentary lifestyles.

There's a belly to brain delay

There's another design feature in our brains that helped our ancestors tuck away excess calories for use in lean times: the 20-30 minute time lag between food filling our stomachs and our brains actually getting the message that we're no longer hungry.

For humans thousands of years ago, any excess calories were converted into fat and housed under the skin as a precaution against times of food scarcity. When the famine came (which would've been a relatively common occurrence) the "greedy brains" survived and those "lean brains" with a natural preference for lower calorie foods would have been more vulnerable to starvation. In other words, those whose brains urged them to gorge on honey, sweet fruits and fatty meats when it was available were unlikely to perish before they managed to pass on their genes: so those brains naturally tempted by high fat / high sugar options became the blueprint for the brain impulses we all now possess.

How to outsmart your brain and become healthier

Modern fMRIs (a test that studies brain activity) demonstrate that reward responses to pictures of high calorie foods are almost always significantly greater than those generated by low calorie food images. Our brains prefer the foods that will help us put on weight. And the more overweight a person is, the greater the difference between the responses to high versus low calorie food. The science also tells us that anyone who develops the habit of eating unhealthy food from dawn until dusk trains their reward pathways to respond more to the sweet stuff and less to the healthy stuff.

The more healthy food you eat, the more your brain increases the reward responses to those foods

Now that we're in an era of food over-abundance (in developed countries at least) there are no periods of extensive food deprivation in which we cannibalise our fatty deposits. Our waistlines are expanding more and more from generation to generation.

In overweight people this is reversible: by eating only healthy and lower calorie foods for a few weeks, the brain re-adapts and increases the reward responses to low calorie foods and reduces those for high calorie stuff. The reality is: you can change your brain!

Healthy eating hacks that will help retrain your brain

  • Any excess sugar we eat is extracted from food and quickly stored as fat, hence why an hour after eating high sugar foods we feel hungry and want to eat more sugar . HACK: Snack on slow release carbs such as wholegrains, fruit and vegetables rather than biscuits, cakes or sweets.
  • High cortisol (the stress horomone) is known to increase the reward pathways' response to high calorie food options AND reduce the influence of brain areas involved in resisting temptation. HACK: Work on reducing stress levels through anything that helps you feel calmer, from reading and exercise to meditation. This will help improve your food choices overall.
  • Making food choices when your blood sugar level is running low impairs brain areas involved in suppressing our urges to act on impulse. HACK: Don't go grocery shopping when you're hungry, or let yourself get to a high level of hunger before you go out to a restaurant full of unhealthy options.
  • Brain science tell us that we can dramatically reduce the power of the impulse to gorge by trying to divert our attention away from temptation. HACK: Don't keep unhealthy food in the house or on your desk. If it's not possible to move away from these foods entirely, you can use your imagination to distract yourself by pretending it is made out of an inedible, perhaps even disgusting, substance!
  • Outsmart the brain to belly delay with a trick from Japan, a country where more people live to 100 there than anywhere else  and obesity is very rare.  HACK:   "Hara Hachi Bu" which means "eat until 80% full."  Put your cutlery down between each mouthful and take longer between each bite. This will help give your brain a chance to register the food in your belly. 

    Dr Jack Lewis has been working with Weight Watchers to help people change the way they think about food to combine an understanding of the latest neuroscience studies into food and decision making. Head to to take a quick quiz to identify your personal approach to food and to find some simple tips and tricks that you can do at home to help tackle the barriers you face.

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