Saxophonist David “Fathead” Newman played on many of Ray Charles' greatest hits. But he didn't earn his nickname because of how he looked when he played the sax.

He got it from his high school music teacher because he refused to learn to read music, preferring to play by ear.

Of course, being a fathead worked out pretty well for him. It doesn't for most people.

A study published in the journal Cell Metabolism reveals that a high-fat diet doesn't just pack on pounds.

Long before you see your belly bursting over your belt, the excess fat (mostly saturated fat and trans fats that are combined with highly processed carbs) has caused neurological changes in your brain.

It turns out that the hypothalamus, which regulates metabolism and helps control your weight, becomes inflamed by a high-fat diet.

That leads to dysregulation of how your body uses energy and manages glucose, and it may set you up for chronic depression by altering a signaling pathway from the hypothalamus that helps regulate emotions.

This shows that ditching a high-fat diet is not just about losing weight (although that's important for your health and longevity), it's also about how your brain works and whether you're happy or depressed.

So stick with healthy fats from salmon and sea trout, olive oil, nuts, avocados, and vegetable oils.

And make sure you consume less than 20 grams (around 200 calories) of saturated fat daily. There's less than 3 grams of saturated fat in a 3-ounce skinless chicken breast, and just under 2 grams in a tablespoon of olive oil.