In the NBC drama series “This is Us,” Kate Pearson (Chrissy Metz) has struggled with her weight since childhood, and she's contended with periods of depression throughout her life.

In one episode, we see a young Kate ask her mother Rebecca for more cookies; her mom suggests that she eat apples instead. Rebecca was onto something.

A recent study finds that adhering to a Mediterranean diet — including lots of fruit, vegetables, and healthy fats like olive oil, along with animal protein as a side dish — can help reduce symptoms of depression.

That's welcome news because rates of major depressive episodes increased 52% between 2005 and 2017, and available depression medications are far from universally effective.

The study, published in PLOS One, involved 76 university students with symptoms of depression — all of whom ate an unhealthy diet.

Half of the participants received money to help them buy mood-enhancing staples and ate a healthier diet. The others ate as usual.

At the end of three weeks, those on the healthier diet reported improvements in mood and less depression, in contrast to those eating a lousy diet.

So does unhealthy food make you depressed, or does depression make you eat bad food?

The answer: both.

Studies clearly show depressed people tend to eat less healthy food, and eating junk food raises a person’s risk for depression.

Our suggestion: If you're feeling blue, make a salad using baby kale, arugula, tomatoes, scallion, avocado, walnuts, and olive oil.