Have you ever eaten food and felt sad afterward? A new study finds there might be a reason for this.

According to the universities of Navarra and the University of Las Palmas de Gran Canaria in Las Palmas, Spain, eating trans fat is now linked to depression.

Sad From Food

Authors of the wide-reaching study followed and analyzed the diet and lifestyle of over 12,000 volunteers over six years.

When the study began, none of the participants had been diagnosed with depression; by the end, 657 of them were new sufferers. Those who took in the most trans fats had up to a 48 percent increased risk of depression.

The unhealthy fats, said researcher Almudena Sanchez-Villegas, are believed to lead to biological changes in the body linked with both heart disease and depression.

Next time you reach for some fast food, remember you might literally regret it later.

Pass The Oil, Please

Researchers also showed that some products, such as olive oil, which is high in healthy omega-9 fatty acids, can fight against the risk of mental illness.

"The participants with an olive oil consumption higher than 20 grams a day (about 0.7 ounces) had a 30 percent lower risk of depression than those without consumption or with a very low consumption of olive oil," said Sanchez-Villegas.

These findings seem to go hand-in-hand with another recent study that found that a Mediterranean diet, which boasts olive oil as an important source of monosaturated fat, may be associated with slower rates of mental decline in the elderly.

Read More:

• Eating Bad Food Linked to Depression (Discovery News)
• Eating Trans Fats Linked to Depression (WebMD)