The video provides peer reviewed evidence showing those eating a plant based whole food (pbwf) diet are on average happier than those eating a diet containing animal products. It offers us two reasons as to why that is. One being that people who eat PBWF are overall in better physical health which then coincides to better mental health. The other fact being that animal products, particularly chicken contains arachidonic acid which causes inflammation resulting in an adverse effect to mental health.

So basically it is sayin that people who eat a PBWF diets tend to be in better moods than people who eat animal products.

Thanks for the question and I hope this helps.

Peace,
The Last Sage