According to a WHO press release from October 2016, the global prevalence of obesity more than doubled between 1980 and 2014 , with 11% of men and 15% of women (over half a billion adults) obese in the last year.

This figure is not only worrying because of what it means for our bodies to store large amounts of liquids and fats; in addition, obesity is related to addiction and certain mental disorders .

A fat-oriented brain

Let’s do a little experiment. As you read the following list of foods, imagine them as vividly and clearly as possible:

  • Chocolate doughnuts.
  • Cream puffs.
  • Ham and cheese pizza.
  • Burger overflowing with sauce.
  • Ice cold drink.
  • Chocolate shake with whipped cream.

Does your mouth water at the thought of such food? That powerful taste, the sweetness of a glaze, the salty taste of fried smoked bacon… Don’t panic, you’re within the norm.

The fact is that many studies show that human beings, by genetics, have a preference for fats and sugars . In fact, that preference turned out to be an evolutionary advantage for our ancestors by allowing fat to accumulate in their bodies, ensuring survival in stages when food was scarce.

Times change: overfeeding on fats and sugars

That these foods had a particularly pleasant taste was not a coincidence : it indicated the presence of such elements. The organoleptic characteristics that precede them: the smell, texture, taste… were a great wake-up call for their consumption, just as they are today.

However, there is unanimity that the current consumption of sugars and fats is excessive in relation to the current lifestyle. We are fully aware that an increase in the intake of these two foods linked to the prevailing sedentary lifestyle does not exactly do our health any favours . And, surprisingly, it is difficult for many people to balance this intake despite the impact it has on the development of multiple diseases such as diabetes, hypertension, hypercholesterolemia or obesity.

So, if it’s so bad for us to eat fats and sugars in the long run… What keeps us in this line? The answer is in our brain .

The Brain Reward Circuit

Also known as the Hedonic or Pleasure Circuit , it is involved in motivation and the feeling of pleasure. It is composed of:

  • The ventral tegmental area : It constitutes the central link of the reward circuit, since its neurons are connected to numerous regions of the brain. It carries out the release of dopamine.
  • The nucleus accumbrens: Increases brain dopamine levels
  • The prefrontal cortex : directs the planning of cognitively complex behaviors, the expression of personality, decision-making processes and the adequacy of social behavior at each moment (among many others)
  • The pituitary: releases beta endorphins and oxytocin, which relieve pain, regulate emotions such as love and positive attachments, among other functions.

What elements activate the brain reward circuit? Among others, love, tobacco, cocaine, marijuana, fats and sugars. But let’s focus on these last two.

The Psychological Explanation of Obesity

The process begins with the intake of foods high in sugar or fat, which stimulates the secretion of oxytocin and dopamine from our brain, which provides feelings of joy, well-being, pleasure and avoidance of discomfort, since dopamine naturally participates in functions such as food or sex.

Thus, after having eaten the doughnuts we imagined above, our body feels good and the well-known hedonic pleasure is produced, which constitutes a positive reinforcement of the “doughnut-eating” behavior (which we will do again). But dopamine (neurotransmitter) and oxytocin (hormone) have a limited lifespan, and when they disappear, the opposite feelings of well-being that we human beings long for remain, thus going from anxiety to sadness. The intake begins again and the cycle repeats itself.

The onset of food dependence

A phenomenon to be taken into account in the functioning of this circuit is that dopamine and oxytocin disappear before the game and, in addition, the doses tend to decrease, so that, if the same level of excitement is desired as at the beginning , the amount or frequency of food intake must be increased, finally becoming addicted.

This process may be related to the development of obesity, diabetes, and binge eating disorder.

On the other hand, there is evidence that the uncontrolled intake of sugars and fats is more prevalent in individuals suffering from obesity compared to normal weight individuals, but specifically in the obese group, is more frequent in depressed and/or anxious individuals .

Do fats and sugars act as an escape pump to tense situations? Research suggests that moments of stress and situations that generate negative feelings do indeed lead these individuals to make high-fat and high-sugar intakes to feel temporarily good, but after the dopamine level is reduced, they again feel anxious and guilty about the lack of control they have shown or about having ignored their eating patterns.

Would you be able to reduce the consumption of processed sugar and saturated fat in your daily life?

To illustrate to the reading public, I share a short documentary about what happens to the body when it goes a month without consuming sugar (you can subtitle it in Spanish).