You are what you eat. And if you're stressed or depressed, you might be able to blame your lunch.

Dr. Candice Seti is the author of Shatter the Yoyo. She's a food psychologist. She studies the brain-body food link.

"It's the idea of nutritional psychiatry and the idea of connecting how food makes us feel. And there are certain foods that make us feel better than others," says Dr. Seti.

Omega 3 rich foods like salmon are great for brain health. Fruits, veggies and seeds? All good.

But other foods can be a torpedo to your mental health. No surprise, it's anything sugary or processed.

Dr. Seti says, "People don't always make the connection that when your brain is healthy your body tends to be healthy, and when you're lacking these things we're more likely to be depressed."

Understanding the why might be exactly what you need to make better choices. And shifting your behavior can really help in stressful times.