Dr Jen Unwin is a consultant clinical health psychologist and has worked in the NHS for over 30 years, helping people with chronic illnesses to improve their lives. She is also former chair of the UK Association for Solution Focused Practice. Charlotte Summers is a published clinical author and expert in digital health intervention. She is also Chief Operating Officer of Diabetes.co.uk, the company behind the Low Carb Program. This talk was given at the Public Health Collaboration conference 2018 at the Royal College of General Practitioners in London.

Dr Unwin starts by asking the audience a question: “is food, particularly sugar and refined carbohydrate, addictive?” To help answer this questio, she and Charlotte read out thirteen statements regarding consumption of sugar and refined carbs, asking the audience to stand up if the statement applies to them. At the end of the exercise, Dr Unwin reveals that these statements are based on the DSM-5 criteria for substance use disorder, which are usually applied to drug use. However, these criteria can apply to consumption of sugary foods for many people, without them even realising it, and this highlights the potential stealth of food addiction.

According to a narrative review, “sweet sensations are one of the most intense sensory pleasures”. It is thought that the reward we receive from eating sweet foods could be an evolutionary adaptation that allowed ancient humans to seek out high-energy foods and put on fat in times of food scarcity, such as in the winter. In modern times, manufacturers of so-called ‘hyperpalatable’ foods exploit this evolutionary system by packing processed foods with sugar in many different forms and combinations. There also exists a metric known as the ‘bliss point’, which is the most palatable level of sugar, salt or fat, or any combination of these, that can be added to a product.

So how does sugar cause our brains to reward us? Dr Unwin explains that tryptopha, the precursor to the feel-good chemical serotoni, is preferentially taken up into the brain in the presence of sugar. This gives us a boost of serotonin when we consume something sugary, but it is thought that if this is repeated too often, the brain can become depleted of serotoni, and so more sugar is needed to give the same reward. Another chemical that is involved with sugar addiction is the hormone dopamine, which is linked to reward and motivation. With constant stimulatio, the brain can decrease its expression of dopamine receptors, again leading to a need for increased consumption for the same reward. Through these two chemicals alone then, sugar can exert a powerful addictive effect, which may even be more powerful than that of cocaine.

Not only does sugar consumption reward us, but it is also subject to something called negative reinforcement. This is when a behaviour is strengthened because it removes negative feelings such as tiredness, cravings and low mood). Dr Unwin opines that this may be especially important to consider for people with type 1 diabetes who can suffer from hypoglycaemia. What’s more, is that some processed food companies and retailers even seem to acknowledge and exploit these properties of sugar in their marketing, as Dr Unwin shows.

There are a number of studies that support the notion of food, particularly sugary food, being addictive. However, there are also some articles that oppose this idea. Dr Unwin addresses one such article and looks into the conflicts of interest. She notes that the sponsor of the article were themselves sponsored by numerous large food companies and associations so, as is sadly often the case, there is a strong possibility of bias in this article.

Self-reported questionnaire data from Diabetes.co.uk and the Low Carb Program suggest that between 15 per cent and 28 per cent of people are sugar-addicted, with rates varying between groups with different forms of diabetes. The rates of sugar addiction appeared to be highest in people with type 1 diabetes, although the sample size was small. Charlotte demonstrates that the Low Carb Program may be able to help people with sugar addiction. 25 per cent of people with type 2 diabetes identified as sugar-addicted, but this fell significantly to under 8 per cent after completion of the 12-week program.

Dr Unwin concludes that more research would be welcomed on the subject of food addictio, but perhaps there needs to be a push to identify this as a real issue. She also opines that the typical advice to eat sugary foods ‘in moderation’ may be rather unhelpful for people who are sugar-addicted. Charlotte adds that, through technologies including virtual reality and gamificatio, there will soon be even more ways to collect data and reinforce learning around nutrition and food addiction.

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