appetite

The new year is barely a few weeks old, and we've already got our first phony panic over fats -- and this time, the claim is that a high-fat diet will cause brain damage.

But don't give up your steak and eggs yet -- because this study didn't distinguish the good fats your body needs from the bad ones that'll swell your belly and rot your brain.

And here I thought we were finally moving beyond lumping all fats together. Maybe next year.

In this one, researchers fed rats a "high-fat" diet, then watched as the parts of the brain that control appetite and body weight in the rodents slowly fell apart over eight months.

They didn't repeat the study on humans (I don't blame them -- who wants to watch fat people eat junk for eight months?), but brain scans of 34 volunteers found that obese people had similar damage in that same region.

So what does it prove? Nothing about dietary fats, that's for sure.

The rats in the study were actually bred to be obese -- and sure enough, they fulfilled that promise. And the obese people given MRIs were, of course, already obese.

Even the researchers admit that means they can't tell whether the brain damage came from the fats in the diet... or if it was caused by the obesity itself.

And like I said, the diet given to the rats didn't distinguish the good fats from the bad -- but since the researchers say the formula mimicked what obese people eat every day, we can assume it was mostly junk regardless of fat content.

So all the study really proves is that a steady intake of junk will cause you to get obese -- and since obese people have already lost control of both their appetite and their weight, OBVIOUSLY that part of the brain is going to be missing a few cells.

But don't blame fats in the diet for that... blame the fats collecting in your waistline instead.

Your belly might be growing... but your brain is shrinking -- and the more you eat, the smaller it gets.

In a frightening study from the New York University School of Medicine, researchers used MRI images to compare the brains of 44 obese people to those of 19 slimjims who were the same age and had the same background.

Those who were obese had less volume in the regions of the brain associated with eating, appetite, and reward. They had smaller orbitofrontal cortices, which control impulse behavior, and more water in the crucial amygdala region.

They also had higher levels of inflammation than the normal-sized volunteers.

In case you're wondering, none of this is good. Put it all together, and here's what it means: When you overeat, you literally damage your brain to the point where it no longer knows how much to eat or when to stop.

The researchers behind the study warn people to eat more slowly and avoid high-fat food, which is missing the point completely.

It's not how fast or slow you eat, but what you eat -- and the natural fats in fresh meat and fatty fish are absolutely essential to the brain and overall mental health, and will keep you slim and trim if you pass on the carbs.

And I don't care how slowly you eat sugar -- it will give you a great, big belly and a tiny, rotten brain.