The brain's food choices are driven by gut neuron signals, metabolic energy availability, and perceived food properties.

“One of those signals comes from your gut and is completely subconscious. This is not the gut microbiome, per se. These are neurons in your gut that are sending signals to your brain that you are unaware of about the nutrient contents of the foods that you're eating. The second signal is how metabolically accessible a given food is, meaning how readily that food can be converted into energy that your brain, not your body, but that your brain can use. And the third signal is perhaps the most interesting one. It's the signal of belief. It's the signal of what you perceive and believe the food that you're eating to contain, and what you think it can do for you health-wise and energy-wise.”