A short documentary released this summer on YouTube shows the impact of eating a junk food vegan diet.
The film directed by Richard Steffens, But It's Vegan, compares two groups of people as they commit to different plant-based diets over a 30-day period.
One group follows a whole food diet, and the others gorge on junk.
But It's Vegan is made by students at the religious Weimar Institute, an educational facility which describes itself as 'a unique blend of spiritual fellowship, academic camaraderie, and opportunities for personal growth'.
According to the film, the students consider their lifestyles healthy, saying: "We exercise incessantly, we abstain from all the bad stuff - no drugs, no alcohol, - go to bed on time, wake up before you probably even think of getting out of bed.
"And you know what the best part is? We're all vegan."
According to the film, the group always thought they were healthy by default, by being vegan.
But they want to put this to the test.
Both groups were shocked by the results, seeing changes in energy levels and mental function among others over the experiment's time period.
You can find out more by watching the documentary here