Bet you can’t eat just one

First published in the NASGP Newsletter on 13th January 2024

Recent research published in the BMJ shows that ultra-processed snacks are addictive. A goldmine for Britain’s powerful food manufacturers, but the consequences – not just obesity with all the attendant risks but tooth decay, low mood and poor concentration – are a disaster for the health of the nation.

Snacking is nothing new. When I lived in the highlands of PNG the big social event was a ‘pig-kill’. Once the pig had been slaughtered, the first bits to be cut off were the ears. They were given to the children to chew to keep them quiet during the lengthy butchering and cooking in the earth oven along with sweet potato and some greens. A snack, but in a few hours everyone would enjoy the real feast.

Food used to be an occasion; now it’s a pit stop. The modern ‘grazing’ culture has blurred the line between a snack and a meal. And the notion that you deserve a treat has blurred the line between a snack and an occasional indulgence or reward. Even dogs are now entitled to ‘treats’.

Breaking off work for a drink and a snack – a few moments to recharge physical and mental batteries – may evolve into a ritualised social occasion. In Sweden fika – a coffee or tea break with cake has become something you share. Nosh was Yiddish speakers’ word for a snack: now everyone uses it as a synonym for a meal. In a few Spanish bars a tapa is still a free olive or two served with a drink, but tapas and their cousins – pinchos, montaditos, bocaditos (known as face-fillers in Argentina), and in China dim sums – have evolved into carefully contrived visual and culinary temptations.  They are an anchor to a social gathering, eaten slowly and communally. And carefully chosen they can provide a healthy balance of foods. They approach being proper meals.

So how do you define a ‘snack’? Walking round the park trying to solve a problem, I kept dipping mindlessly into my pocket for a handful of Indian nibbles. I’m snacking. By the time there were none left I had come to a decision, and I began to look around. A guy in Lycra lounging next to his bike, inspects the core of his apple. Like me, he’s tanking up on one-dimensional fuel. His snack is healthy and freighted with virtue, but neither my snack nor his would suffice as a continuous diet. A snack lacks variety and is eaten without much attention.

The authors of the BMJ paper reported levels of food addiction in adults comparable to alcohol and tobacco. There isn’t direct data on children, but under-10s are developing diet-related fatty liver disease. The authors describe the likely level of addiction as ‘unprecedented’.

Their study distinguishes between healthy foods like apples and unhealthy foods like my Indian nibbles. There are two characteristics that distinguish unhealthy foods from home-made foods. The first is an unusual and characteristic ratio of fats to carbohydrates. When this hits the stomach it stimulates a very powerful response from the brain reward system.

Snacks don’t give the brain time to suppress ghrelin production, so it goes on and on stimulating eating.

The second is their speed of delivery. We don’t yet know which specific chemical or chemicals are the ‘smoking gun’ for addiction, but ultra-processed foods (UPFs) contain additives which modify the flavour and mouthfeel, which makes them easier and faster to consume. And so, UPF snacks affect the brain more rapidly. Manufacturers know more than most doctors how the hunger hormone ghrelin works. They exploit the fact that these snacks don’t give the brain time to suppress ghrelin production, so it goes on and on stimulating eating. This triggers a dopamine high, followed by a crash which is only eased by eating more of the same. So UPFs have addictive moreishness built in.

Ultra-processed snacks are ubiquitous, and they are packaged to confer durability and portability. Marketing has caught on. Cinemas offer huge tubs of popcorn at the ticket counter. Advertisers show families on the sofa in front of the television with huge packets of crisps. Encourage snacking ‘on the go’ and even my generation, roundly told off for eating in the street, and the French, who would traditionally not sabotage their sacred meals, may be tempted to snack as we walk.

How can we tackle what Prof Tim Spector calls the metabolic roller-coaster which is an ultra-processed snack-filled diet? Humans don’t need to graze. Our guts, like our brains, need downtime to rest and repair. In January 2022 Jamie Oliver and his fellow campaigners got to meet Education Secretary Nadhim Zahawi to put to him the terrible quality of school meals. Zahawi made the right noises but took no action. Later in 2022 the same government which commissioned Henry Dimbleby’s National Food Strategy withdrew from even the most modest of its recommendations. The justification was that since UPFs are cheap, poor families rely on them for much of their nutrition.  Since 2017 when government minister Michael Gove derided ‘experts’, royal colleges and media-prominent doctors don’t even get a hearing. So there isn’t much chance that a government grubstaked by the food industry will stand up to the might of its marketing.

GPs have plenty of opportunities to enquire about patients’ eating habits. We are likely to be told what the patient deems we want to hear, so we probably need to ask directly about snacks. But how can we persuade patients to change their food habits?

Everyone knows a chocaholic, but addiction to ultra-processed snacks is something new to most people. A few patients who acknowledge they have a problem, and have the resources, may choose to attend a private food addiction clinic.  And I’ve discovered there is an Overeaters Anonymous. Like Alcoholics Anonymous they have meetings in person or online and they use same the 12-step programme. 

Little hands reach out to the child-level processed snacks at the supermarket check-out. If their parents read the list of ingredients, they might be put off buying them next time. Is it too much to hope that, if children became aware of the dangers, kid-power might persuade parents to change their habits, as it did with climate change and smoking?

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