Ever notice how one cookie turns into a whole bag? Researchers from the University of Southern California found that high-fat, high-sugar diets can boost activity in the brain&rsquo;s reward center and tweak the hippocampus, which is key for memory. Sugary, salty, fatty bites trigger a flood of dopamine which is the brain's feel-good chemical, making you crave more. Over time you need even more ultra-processed food to get that same buzz.
Although, it gets trickier. Your brain also stores these moments in its memory files. A whiff of pizza or a sight of fries can trigger a vivid memory that sparks a sudden craving even if you&rsquo;re full. Scientists found that neurons in your memory hub, the hippocampus, record tasty details. Those memories quietly whisper, &ldquo;Grab another slice,&rdquo; even when you didn&rsquo;t feel hungry at all.
'Junk food' also messes with your brain hormones. It increases your 'hungry' hormone, ghrelin, and even hacks the serotonin, so you get a quick mood boost followed by a crash. When you eat lots of processed foods, your brain may start ignoring leptin, the hormone that tells you to stop eating, making you overeat. In the long run, sugary and fatty diets have been linked to memory slip-ups and slower thinking.
In short, 'junk food' is a delicious trickster. It makes your brain happy now but tugs on memory and brain signals so you keep coming back for more, even if your brain feels a bit foggy later.