sorry for a not scientific answer, this is general knowledge.
you can try to search for proofs you need.
there are several different types of unhealthy food and the resulting addiction/desire to eat them. the unhealthy food tricks the brain.
the brain is built from cholesterol partially.
the brain can make cholesterol from carbohydrates.
so so-called "unhealthy" food it is good for you kind of. unless you are sick.
so some times a moderate amount of cholesterol is good for you in general, the brain can make its own cholesterol. cholesterol supports memory.
cholesterol is bad if you have an internal wound like an inflammation, maybe of blood vessels or heart arteries. cholesterol made by the liver usually patches the would holes. later to be fixed using protein(if there is also vitamin c). however, if there is an inflammation going and there is a wound filled with cholesterol, new cholesterol will stick to already existing cholesterol. and clog arteries worse.
depriving the brain of cholesterol deprives memory. because neurons make vesicles - like small soap bubbles filled with dopamine that marginally pre-excite neurons. those vesicles are made of cholesterol. if you ingest something that dissolves cholesterol for a long time like a statin or antioxidant you will lose memory and lose the ability to form memory.
also, the brain is energy hungry, so it brain gets activated on high energy foods. however, if fructose or sugar is ingested with food. a large percent of it is stored into fat. using insulin that is made from sugar.
like things that make the brain make neurotransmitters like acids, ions, and sweet poisons are bad for you.
they trick the brain and stress the brain. things like coffee and sugar and sodium glutamate. coffee makes adrenaline and ticks you to release saved energy.
sugar acts on dopamine center and tricks you think you do something good even if it is bad. sugar also gives you some glucose. however, all dopamine from sugar is consumed immediately.
some other things dopamine-making:
the brain seeks dopamine, and while on dopamine the brain does not think rather acts as before in an automatic manner. like, do the same thing again. also if the situation not as before the brain will mistake. sometimes brain confuses one thing to another. because they both make the same level of result. one real one fake. the fake quicker and you need to do it again and again. so people fall for a quicker and easier way. the solution is to delay time, to prevent instant action and try to solve basic body needs like rest and food