If eating was as simple as filling a car with gas, we would strictly nourish ourselves for energy purposes. In reality, we sometimes eat when we don’t need to. People snack when they’re stressed or sad. We may, for example, try to make the most of a breakfast buffet, or spot a lonely cookie in the cupboard. It’s the equivalent of circling back to the gas station despite a full tank of it — completely absurd.
Except, filling up your car and eating aren’t exactly the same. Unless you find the bright lights and diesel fumes particularly thrilling, you won’t get the same dopamine rush that comes from munching on a Twix. In fact, the high fat and sugar content of processed foods activate the brain’s reward pathways and drive us to consume more. Studies have shown that calorific food can modify brain structure by stimulating neural pathways that encourage us to seek out more food, more often.
Scientists also believe that overeating energy-dense food is an example of a learned behavior. If tasty food is consumed regularly in the same context, then we may come to associate random things in our environments with eating. Associating food, or other stimuli, with unrelated cues is known as classical conditioning. This phenomenon was first demonstrated by the Russian scientist Ivan Pavlov. Pavlov trained dogs to associate the sight of food with the sound of a metronome. After just a few trials, the ticking sound alone caused the pups to drool in anticipation of their dinner.