Doesn't the food we eat contribute to some mental disorders?

Like depression or anxiety in some cases?

Yes it does.

If you eat less you get less nutrition, when that happens sometimes parts of your brain work improperly. This commonly causes chemical imbalances that can cause a number of mental illnesses.

Absolutely- eat a lot of sugar and crash- same with caffeine.
i have anxiety and depression which it is bi-polar 1 that also has manic but with my anxiety, caffeen or uppers things that make u race..... which make u go up, and then come down, which will cause depression... i have heard certain foods help work with it. like have heard if u have a cup of hot choclate in the morning helps i did try a natural lithium called serenity i liked it... but for me i needed alittle more..... i looked it up on the internet.
well, i believe that to a sense, i mean, look around and you ll see most people eating crap. they are not getting good nutrition and are eating lots of fast food that is over processed, and junk food. it is bringing people down
I have terrible anxiety problems that I constantly try to resolve by eating "the perfect diet" of fruit, vegetables, protein and a source of wholegrain when I can. I notice little change.

If the problem is there, it's there. I'm not saying it's a bad idea to eat healthy, or that eating healthy won't HELP some people to a degree. It's just not a case of snapping your fingers and it goes away though.

It's a hard thing to measure, come to think about it. I think your body is more complex than a simple "lack of nutrition means brain parts don't work" as the body can break down a lot of different foods and absorb what it needs from many things, including, to a degree, fast food. However, fast food is a source of LDL cholesterol and can lead to weight gain - however, fats can also be broken down and used, so if the body needs it, usually enough is there to function even in extreme circumstances. Unless you're heavily underweight and then that is different.

However, I like eating healthy, it makes me feel like I'm doing what I can so maybe subconsciously it helps.
yes todays food is filled with things that are bad for us, read about it online on any depression website.
You are what you eat and if what you eat's off the street then who are you?

Make of it what you will...