Why Are We Overweight?
Dopamine tells your brain to “want” things.
To understand how this works biologically, I suggest you learn about the incentive salience model by googling an expert in the field, such as Kent Berridge or Brian Knutson.
Functionally, you can imagine that wanting exists on a dopamine continuum going from 0 to 100 dopamine molecules. For this article, 100 means your brain has released all of its dopamine, which causes you to *want* so much that you might give your life for the object of *wanting*. Note: this model has been validated in rodents, who will continue to press a lever for cocaine rather than eat or sleep; eventually they die.
Now let’s go back to our 100 molecule dopamine continuum.
Let’s posit that natural foods release 10 out of 100 possible dopamine molecules. You really want that apple.
Next let’s posit that sex releases 20 out of 100 possible dopamine molecules. You really want him or her, and you will even skip a meal to have sex.
Now we are approaching the problem.
Sugar and other man-made post-industrial nutrient compounds are *novel* for the brain.
When you eat a candy bar, your brain (using our hypothetical 0 to 100 dopamine continuum), releases 30 dopamine molecules. Your brain is naturally wired for reward. But the core survival functions, such as food and sex, can be usurped or “hijacked” (google, Nora Volkow) by novel compounds, such as drugs of addiction, alcohol, and foods containing sugar.
When 30 or 40 hypothetical dopamine molecules get released, you **want** that candy bar (Do you want it more than a hug, a sunset, or time with someone you love?).
Therefore, you will eat the candy bar repeatedly even if it doesn’t taste good and harms you.