I hope you all had a wonderful Easter and enjoyed celebrating all things to do with new beginnings and springtime in the way that best suits you. I don’t know whether it’s a usual theme or whether I just particularly noticed it this year, but it did seem as though, with all the Easter chocolate around, I kept hearing people say how they’re addicted to chocolate or sugar. One person even mentioned that infamous mouse study, where the researchers gave the mice the option to choose sugar or cocaine and the mice chose the sugar, leading the journalists who reported on the study to conclude that sugar is even more addictive than class A drugs!! (Just to reassure you, that was not a very well conducted study, and the mice had been starved for 5 days before they were offered the choice between the sugar or cocaine. They were just being sensible mice going for the energy first. Nothing to do with addiction.) But it did get me thinking. As a nutritionist who graduated in the UK, we were always taught that food can’t be addictive any more than air or water can be. After all, you can’t really use the word addictive when it’s something you need for survival. Is that the whole story though? Whilst of course we do need food for survival we don’t need sugar, or any of the hyper-palatable, highly processed foods such as crisps, doughnuts, or basically anything that contains high fructose corn syrup. Could some foods be addictive, but not others? Functional MRI scans measure brain activity by detecting changes in blood flow to different areas of the brain, and what’s really fun about them is that you can have a group of people doing different tasks while being scanned and see how their brains respond, and which areas light up.
A group of researchers thought it would be a good idea to put some people into one of these scanners and give them different foods. What they found was that when they gave people chocolate cake the pleasure centres of the brain lit up like fireworks at a 4th July party. The participants gained a lot of pleasure from eating that cake!! However, when they repeated the experiment a few times, the pleasure diminished slightly each time. To get the same response as the first time, they had to keep increasing the portion size. As humans, we’re almost hard-wired to repeat behaviours that activate the pleasure centres of the brain. So the results of the chocolate cake study would suggest that maybe there is potential for some kind of behavioural addiction to some foods. Some further studies that have come out of America have also noticed a hormonal response to certain sugary foods too. Specifically, the neurotransmitter dopamine. Often referred to as a pleasure hormone, dopamine is more complex than that. It would be more accurate to describe it as the motivational aspect of reward-motivated behaviours. Anticipating any kind of reward increases dopamine levels in the brain, which is what then gives the feel-good factor. Even in the absence of a definite feel-good moment as a result of a particular behaviour, we still chase that dopamine hit though, so it’s no surprise that its levels in the brain are linked to most drugs and yes, alcohol. Even when we lack the feel-good factor and we know something is bad for us we still chase that reward. When we think of sugary or hyper palatable foods as being capable of moderating which areas of the brain light up in an fMRI scanner, or altering levels of dopamine in the brain, it certainly makes sense that some people feel as though they are addicted to them in both a
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