You might assume that nothing would make you happier than polishing off that super-sized double cheeseburger meal with a large milkshake, but actually the opposite is true -- recent studies suggest that eating junk food actually makes you depressed. Researchers at the University College London in England found that people who regularly indulged in processed, high-fat and sugary foods were 58 percent more likely to suffer from depression than those who eat a healthy, balanced diet.

"There seem to be various aspects of lifestyle such as taking exercise which also matter, but it appears that diet is playing an independent role," Dr. Eric Brunner, lead author of the study, told the Daily Mail.

So is a healthy diet really that much better for you? The study, which appeared in the British Journal of Psychiatry, concluded that all the nutrients found in wholesome food compared to fast food affect mental health. High levels of antioxidants, folate and omega-3s are being credited with the positive mental health of those with a balanced diet. On the other hand, unstable blood sugar levels contribute to high levels of depression in junk food eaters.

The bottom line? Junk food won't make you happy. Keep that in mind next time you're weighing up the merits of a salad versus a Whopper at lunchtime.

In fact, poor eating may send you to therapy -- it did for Kevin Federline.