Our close biological relative, the orangutan, is a fruit lover. Those tasty treats make up around 90% of its diet. In fact, the big Os feast on more than 400 varieties of plants.

Maybe that's why they look so chill as they amble through the rainforest. 

An Australian study published in the journal Clinical Nutrition found that for middle-age humans (ages 45-65), eating about 16.5 ounces of fruits and vegetables a day helps them stay chill too. It turns out eating like that reduces your stress by at least 10% — enough to make you feel substantially better.

The researchers theorize that the vitamins, minerals, flavonoids, and carotenoids in fruits and vegetables reduce body-wide inflammation and oxidative stress.

Inflammation is related to mental health by disrupting your gut biome and increasing levels of stress hormones (which disrupt the gut and the brain). Runaway oxidation is essentially rusting your bodily systems, increasing risks for cancer and arthritis and amplifying stress responses. 

What do you have to eat to get 16.5 ounces of fruits and veggies a day? Not that much. An average apple weighs about 6.4 ounces. Two cups of spinach leaves equals a bit over 2 ounces. The U.S. Department of Agriculture says a banana averages around 4 ounces, and one and a half cups of broccoli florets equals about 4 ounces. There you have it.

Making sure you eat at least that much shouldn't stress you out. Once you get that down, we recommend you relax into two to four more servings of fruits and veggies daily.