Have you ever wondered why you crave fast food despite being aware of its negative effects on your body? There is evidence that junk food can be addictive. Fast food consumption has been comparable to drug abuse. Brain imaging studies suggest that when displayed pictures of alcohol and fatty foods, similar areas of the brain linked with motivation, learning and memory are activated.
It is crucial to note that hunger is a different phenomenon to that from craving. Craving is associated with the brain’s reward system while the hunger loop is connected to the hypothalamus. Therefore, when people are craving food, they might not necessarily be hungry. However, they might continue eating fast food despite reaching a state of satiety i.e. fullness.
Chronic intake of unhealthy food can lead to changes in one’s reward pathways. Similar to drugs of abuse, a diet high in carbohydrates, sugar and salt can lead to a surge of dopamine in the brain. Fatty food such as burgers and pizza heavy in carbs and salt can lead to a quick surge in dopamine leading to an immediate feeling of pleasure.
It is interesting to note that unlike fatty foods, when healthy foods are consumed, the neurotransmitter serotonin is released. Serotonin enhances mood and is associated with a feeling of “liking” while dopamine gives pleasure and is associated with a feeling of “wanting”. Serotonin release is hindered by the consumption of fatty foods. This suggests that fatty foods induce immediate pleasure, however, might not elevate one’s mood.
Furthermore, emotional eating is usually linked to the consumption of comfort food. Comfort food is often heavy in carbohydrates, salts and sugars. It is interesting to note that as the name suggests, comfort food provides immediate comfort by alleviating levels of stress and offering an immediate reward. Evidence shows that food high in sugar can reduce the activity of the hypothalamic-pituitary-adrenal (HPA) axis i.e. the area of the brain partially responsible for regulating stress. Additionally, the consumption of comfort food leads to the release of hormones that facilitate a reduction in stress levels. Reduced stress can further escalate the desire for fatty food, thus activating a vicious cycle.
Cravings can be activated by certain triggers such as cues. For instance, the smell of pizza wafting from a pizza shop or the sight of a popcorn bucket in a movie theatre can trigger cravings for certain foods. The reward pathway is linked to memory i.e. hippocampus. Therefore, the brain is able to remember the feeling of reward linked to the consumption of fatty foods and thus one is more likely to repeat these actions in the future. External cues in the environment trigger cravings due to the sensitized associative learning between environmental cues and substance of choice.
Cravings usually arise from outside factors, for instance, external stimuli or negative events in one’s life drive the craving for fast food. It is interesting that fast food can alter one’s mood. These factors might ultimately lead to disorders such as fast food addiction and obesity.
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