Can your favourite foods really be addictive? Here’s the truth

Food addiction is a topic of ongoing research, and it is not universally accepted as a distinct addiction like drugs or alcohol. People talk about being addicted to certain foods, but many scientists say it is impossible to be addicted to food as we need food to eat. Cigarettes, alcohol, recreational drugs, opiods etc. aren’t essential for life and have been shown to have specific effects on the body and brains of some people.

I don’t want to get into a long discussion about this. I’d just say that some specific foods for some specific people act as addictive substances.

Many people do describe compulsive and uncontrollable urges for certain foods. These are often high in sugar, salt, or fat. Some common examples of potentially addictive foods include:

The cravings are almost always for high sugar and/or highly processed foods.

Does some food alter our brains and taste preferences?

There was an interesting study done on the effect of yoghurt on people’s brains that throws light on this.

All the participants followed their normal diet for 8 weeks. In addition, they ate a small yoghurt twice a day. The researchers gave 26 volunteers a small yoghurt that was high in fat and sugar. The other 23 participants received yoghurts that contained the same number of calories but were low in fat and sugar.

The researchers wanted to see if taste perception changed during the eight weeks.  At the beginning of the eight weeks, and again at the end, participants rated puddings with varying fat concentrations, and apple juice with varying levels of sweetness. Participants rated them for fattiness, creaminess, oiliness and sweetness.

They also rated them according to how much they wanted and liked them. The researchers found that the participants who had eaten the high fat/high sugar yoghurts liked the low-fat foods much less at the end of the study than they had at the beginning.

Now we’re getting to the more interesting part of the study. The researchers used an MRI scan to look at what was going on in the participants’ brains. The volunteers’ brain activity was measured before and after the eight weeks. They found that those participants who had eaten the high fat and high-sugar yoghurts had an increased activity in some brain regions when presented with a high fat/high sugar milk shake.

The milk shake activated the motivation and reward system of the brain more than it would have done without the 8 weeks of high fat-high sugar yoghurts. This higher level of activation also continued while they drank the milkshake.

The group who had the low-fat low sugar yoghurts didn’t have this change in their brains.

The researchers concluded that even a short intervention like this shifted the participants’ preference to wanting more high fat-foods. Their brains had unconsciously learnt to prefer high-fat snacks.

This is not just about yoghurt – you may only eat low fat and low sugar ones. The implications are much broader. This research explains that unhealthy food stimulates your desire for more unhealthy food.

Manufacturers understand this process very well. It is definitely in their interest to get the right levels of salt, fat and sugar to stimulate your brain in this way. That way they sell more of their products!

Do gut bacteria tell their hosts what to eat?

Our gut is full of microbes. Having a diverse population of bacteria in the gut benefits our digestion, your immune system and even your mood. In fact we are probably only at the beginning of understanding how important gut bacteria are for our overall health and wellbeing.

An article in Scientific America looks at the research on fruit flies. The bectaria in the gut are shown to influence the foods that the fruit flies want. This is not for the fruit flies benefit, but for the bacteria’s benefit.

Sadly most of the work to date has been on animals, but I am confident that over time human studies will show that some gut bacteria “encourage” you to eat more sweet, processed food, whereas others encourage you to eat more fibre rich food. The bacteria’s influence is down to the type of food they prefer.

Over time it is possible to change the predominance of particular bacteria by changing what you eat. A diet rich in plants and minimally processed food encourages the bacteria that want to eat more of that type of food. This creates a virtuous circle with the good bacetria encouraging you to eat more of the food that is good for you.

Why is it so hard to eat healthily?

We have two mechanisms that are working against you eating healthily.

High fat and high sugar processed foods change the brain’s reward centres.

An unhealthy diet seems to prompt the bacteria that like that sort of diet to encourage you to continue to eat it.

Both of these may explain why some people find it hard to move to a healthier diet. If you’re one of these people, it may be that you need to think about what’s going on as akin to an addiction. It’s the same areas of the brain that are being over-stimulated. You can recognise this and give up and just eat unhealthy food, with all its dangers for your long-term health.

Or you could recognise that it’s going to be difficult initially, just as it would be if you were giving up smoking, but bit by bit it will get easier if you stick to healthy food.