Contrary to the weight you gained when you demolished your kid’s Halloween candy, sugar actually used to be useful. Our early ancestors depended on sugar-rich foods for quick survival calories while hunting and foraging. Back then, grabbing a handful of berries could have been the difference maker between getting dinner and being it. Now, however, the average person unconsciously pounds sugar like they’re manually tilling fields all day, and it might be slowly turning our brains into mush.

According to researchers from the University of Technology Sydney, in a new study published in Nutritional Neuroscience, the team analyzed 27 preclinical studies involving rats and mice fed high-fat, high-sugar diets. Researchers wanted to know whether switching back to healthy food could reverse the cognitive damage caused by years of eating sugary junk.

The answer is a bit of a mixed bag, ranging from an unencouraging “kind of” to a depressing “not really, you’re screwed.”

The good news is that memory did improve once the rodents stopped eating the contents of a 7-Eleven. The bad news is that their brains never fully bounced back to the level of animals that had always eaten healthy diets. And then there’s the even worse news: researchers found sugar itself is the problem, and nothing else.

An Ouroboros of Sugar-Fueled Brain Damage

The road is recovering from high-fat diets showed some improvement, but the high-sugar rodents, or the ones that combined high-fat and high-sugar diets, didn’t show any meaningful evidence of recovery.

The researchers narrowed down the damage to a specific region of the brain, the hippocampus, the part responsible for learning and memory. Funnily enough, it’s also the part of your brain in charge of appetite regulation. All the sugar you’re eating is doing damage to the part of your brain that would help you stop eating so much sugar if you weren’t damaging it with all that sugar.

The researchers say that re-balancing your diet and eating healthily still provides benefits to your memory, but the idea that you can unravel the damage to your memory caused by years of eating as if you live in Wonka’s factory with just a few salads and steamed chicken breast is unlikely.

If you want to protect your memory, go easy on the sugar, doing your best to avoid overloading your system with the stuff, because while you may be able to shed some of the pounds one day, the havoc it wreaks on your brain is damage you’ll never undo.