Eating fruit and vegetables ended my depression

I recently stopped eating various forms of slop (fast food, pastries, donuts) and replaced the slop with a deliberate meal plan focused on yogurt, flax/nuts/whole grains, fruits and vegetables (sorry to say I basically never ate fruits or vegetables as an adult lmao).

The results have been insane: within 10 days, I feel a sense of productive optimism. I don't have "crashes". I don't feel much stress. I often feel happy. I feel much more clear-headed. These outcomes are backed-up by emerging research on the "gut-brain axis" - gut flora play a key role in mood. If you're eating slop, your gut flora will be fucked-up. Fruits/vegetables feed them.

Anyone else change their diet radically and experience this? More to the point, what the fuck is wrong with Western society that this kind of obvious approach ("you are what you eat") isn't heavily prescribed and promoted? Only thing making me depressed today is thinking about the years I lost and the millions of people who eat slop till they die prematurely, while having had a life deprived of a lot of happiness they could have had...