It was set by a listener to BBC's "scientific detectives", biologist Adam Rutherford and mathematician Hannah Fry, presenters of the radio program "The Curious Cases of Rutherford and Fry" dedicated to exploring the mysteries of daily life sent by the public.
"Why does bad food taste so good?" Alan Fouracre asked from New Zealand and stated that he referred to things like "sausages, french fries and chocolates".
To find out, Rutherford and Fry began going to Material Scientist and Food Lover, Mark Miodownik, who explained why we literally walk our mouths when we see these unhealthy foods.
"(We have) taste buds for the sweet, for the salted, the sour and the bitter, and all weep to be fired by this food," said Miodownik.
"And (when you eat them) they light up, there is a symphony of taste (in your mouth)."
But the tongue is not the only sinner that leads us down the wrong path of nutrition … The first one that incites us to sin is our nose.
It smells rich
"What drives our demands is our sense of smell," the expert explained.
The smell of a particular type of food causes our digestive system to ignite and claim to be fed.
And when the food is in our mouth, it is also our nose that allows us to feel all the flavors that are taste.
"They are thousands of tastes, it's something very sophisticated," explained Miodownik.
The role that smells play explains why many of these foods – such as a hamburger or fried bacon – are irresistible to us when they are hot, but we are no longer interested in them cold.
"As food cools it loses its taste because there is less heat that converts volatile molecules into odors inside the mouth," the researcher said.
But if heat is an important factor in explaining the attraction of junk food, what about soft drinks, is considered one of the biggest culprits in the rise in obesity in the world?
Or with chocolate and sweets that cost us so much to eat in moderation.
One of the world's most recognized food experts, Professor Linda Bartoshuk of the University of Florida, explained the program, why foods full of sugar attract us so much.
"The fuel in the brain is glucose, which is sweet, and throughout evolution, our brains have evolved in such a way that we love the sweet because we need it," he said.
This explains why we were looking for sweet foods and why we enjoyed them so much.
Bartoshuk points out that this connection "comes from birth" and even before: it has turned out that even fetuses enjoy the sweet.
"A pediatrician did research in the 20s by injecting saccharin into amniotic fluid into a pregnant woman, and the fetus drank the fluid," he said.
The observations showed that the fetus had enjoyed the sweet drink.
Full of recipients
We have already seen how our tongue, nose and brain make a plot against our will to eat healthy. But the challenge does not end there.
Our body has several "taste receptors": not only in the mouth, but also in the stomach and gastrointestinal tract.
And these recipients also have their "urge".
"For example, fat and proteins cannot be detected in the mouth, but you swallow them, your digestive system converts them to fatty acid and glutamate, and now you have receptors in your stomach that tell your brain that you just enter this amazing fat and protein, "Bartoshuk describes.
These associations work subconsciously so that they can lead you to some form of food without knowing or understanding why.
The psychological aspect
Rutherford and Fry also analyzed the unhealthy food from a psychological point of view.
They discovered that categorizing this food as "bad" could make it more desirable.
"When you classify a meal so badly, you create a sense of guilt in eating it that makes you think it should be particularly pleasant and can make it harder to resist," said Anthony Warner, who writes about food under the pseudonym Den Angry Chef (chef angry).
"It's like putting it on a pedestal and making it a forbidden food, it will make you have more," he said.
According to Warner, the most guilty people tend to have the least control over what they eat and the hardest to improve their eating habits.
"By calling it bad you make it harder to resist," he said.
So what is the solution to eating healthier, according to BBC researchers?
"Eat moderately and enjoy it, we need fat, sugar and salt food."
"Just don't eat too much."