Interviewer: Hello listeners, today we are going to talk about junk food and its effect on your body. We have Dr Jessica Culland in the studio, a registered nutritionist and dietitian based in Los Angeles, USA, who will shed some light on junk food from the scientific side. Dr Culland, welcome!

Jessica Culland: Hello, thank you for inviting me to this programme.

I: Dr Culland, why is junk food, and especially fast food, so popular?

JC: It’s a complex issue and there are so many possible reasons for it. The fact is that over the years many fast food items have become more extreme, their size has increased, their taste has been enhanced, and, as a result, nowadays more people are eating more fast food more often. It’s fast, readily available, relatively cheap, and it tastes good.

I: Oh yes it does! So what is it about fast food that makes it taste so good while at the same time it makes us feel so bad?

JC: Well, you may not realise it, but such food has been carefully engineered to blend the appropriate proportions of salt, sugar, and fat in order to stimulate pleasure areas in your brain and release dopamine, the hormone of happiness. But it’s more than that: fast food has been designed in a lab to be intentionally craveable, every little detail of it is the work of brilliant scientists, mathematicians, and flavourists.

I: Can you explain it a little bit more?

JC: A mathematical model calculates the precise amount of sugar necessary to bring your meal up to the point of optimal concentration known to maximise sensory pleasure. The food is injected with special natural flavour extracts to give cheap ingredients an unmatchable boost of fake flavour. Additionally, the colours of the packaging and the fast food restaurant decor also aim to stimulate your brain to provide maximum fun and entertainment, so it’s no wonder that, despite our best efforts, homemade meals cannot compete with fast food. 

I: Does it mean we don’t eat homemade meals any more?

JC: No, but one in three Americans prefers to eat at least one fast food meal every single day. Unfortunately, the more fast food we eat, the less delicious natural food seems to taste in comparison, and we crave fast food even more. 

I: What is the scientific explanation for this phenomenon?

JC: The release of dopamine when we eat a perfectly engineered burger results in more than just the feeling of pleasure. Dopamine is the neurotransmitter involved in creating habits and addictions. Eating fast food regularly amplifies and sustains your craving and motivation to repeat the experience that caused pleasure.

I: And why do we get hungry again so quickly after eating junk food?

JC: Junk food is food which has been processed and refined, it doesn’t have natural fiber any more so it can be broken down and digested very quickly. This results in an instant boost of energy from glucose in our bloodstream, but its overflow is usually unlikely to be used at once, so it is turned into fat by the hormone insulin instead. Soon your sugar high subsides and you are hungry again, even though the typical fast food meal contains almost as many calories as all the meals from the entire day. At that moment, your body is trying to restore your blood sugar to a healthier level so you might experience cravings, especially for unhealthy food which you have just eaten.

I: So how can we get out of this vicious circle and not let ourselves become addicted to junk food?

JC: The answer is simple really: swap junk food for healthy alternatives. There are so many options you can choose from!

I: Can you give us some examples?

JC: Of course! You can start with some changes to your breakfast choices: instead of sugary cereals, choose low‑sugar cereals like oatmeal, exchange the half‑fried eggs into boiled ones, and go for whole grains rather than refined grains. Make some better choices while eating dinner meals too: choose lean meat over fatty steaks, and generally replace any deep fried products with baked food. 

I: Is what we choose to drink equally important as our food choices?

JC: Absolutely! Most people think that all those drinks with “light” or “diet” labels will help them reduce their sugar intake, whereas the truth is that they usually have artificial sweeteners which are 200‑13,000 times sweeter than regular sugar, plus they contain certain acids which erode tooth enamel. You can also switch to much healthier options, for example instead of fizzy drinks try lemon water, and instead of using sugar, try cinnamon. By the way, herbs and spices are also a great alternative for salt.

I: Well, you certainly gave us some food for thought. Thank you Dr Culland, that was a most interesting talk.

JC: Thank you, my pleasure.