Addictive foods

For some, it’s milk chocolate. For others, it’s crisps. I’ve even met one person who simply could not keep away from mini rice cakes spread with butter. Almost everyone who has struggled with their weight has a few foods that can be relied upon to wreak havoc on even the most carefully-planned diet.

Aside from being a source of immense frustration, these foods also share another feature: all of them contain a ratio of two parts carbohydrate to one part fat.

The science backs this up. In 2015, researchers from the University of Michigan took 120 students, offered them a choice of 35 different foods, and asked them to fill in the Yale Food Addiction Scale, a measure of how addictive you find a particular food. The foods were then ranked from one to 35 by the students. Top of the list of “most addictive foods” was chocolate, followed by ice cream, French fries, pizza, biscuits, crisps, cake, buttered popcorn and cheeseburgers. At the bottom were salmon, brown rice, cucumber and broccoli.

Looking at the foods when listed by content, it is striking that each one of them is made up of approximately 2g carbs to 1g fat. Which – it turns out – is the exact same ratio of fat to carbohydrate that is present in the very first food that we consume – human breast milk. In fact, milk is one of the very few natural foods that contains high amounts of fat and carbs all mixed together.

The infant brain is super-sensitive to experiences during early years, laying down neural reward pathways that last for life. It is not surprising, then, that the food that gives us our first feelings of reward lays the foundation for our later food cravings.

Some might conclude from this that there is very little that we can do to alter our hard-wiring. We’re not babies any more: our brains are no longer forming their first connections. But this would be wrong. A growing body of evidence shows that the human brain is a continuous work in progress: even in midlife we can remodel and reshape its deep-level connections, allowing us to break free from lifelong patterns of behaviour. And for a population caught in the grip of an obesity crisis, this awareness could quite literally save lives.