"This is correct, but if you have a nutritional disorder - a physical illness or disease - then this needs to be treated first BEFORE considering "psychological" or other factors. You cannot argue with physics and chemistry."

That is totally untrue, and you haven't got a thing in physics (where did that one come from) or chemistry to even begin to back you up.  You haven't presented a single FACT to support your irrational train of thought.

"Three recent studies document that consumption of processed foods increase odds of depression, and not only that, but those high protein, high fat diets (high in animal products) are also linked with more depression. The diet to protect against depression – that is simple, a high nutrient, plant-based diet outlined in my books, Eat for Health and Eat to Live."

I'll go back to my original point, a healthy diet may assist in the healing of any disease, mental or physical, but it is not the cause of depression and none of your references even hint at it.  Also, they are neither peer-reviewed studies nor are they studies by accepted sources.  I would say that alcohol is a much bigger contributor to depression than nutrition.  

One other point - which comes first?  Depression?  Or unhealthy nutrition?  I can guarantee you that when a person becomes depressed and they have no respectable self-image that they will do all sorts of harmful things to their bodies and poor nutrition is just one of them.  

Regarding alcohol and depression you can find all sorts of connections - much more so than the contributing factor of nutrition.  Below is but one small link between alcohol and depression and you can find a zillion others all over the place.

http://depression.about.com/od/drugsalcohol/a/alcoholanddep.htm

Depression and Alcohol Problems Go Together

When alcohol wears off, you will be more depressed than ever.
{Ann Landers' to readers, Dec. 5, 1993, as well as many other medical sources}

Depression and alcohol problems often go together, but the evidence suggests that in men alcohol use preceded the depression, whereas in women the depression precedes the alcohol use.
{American Journal of Epidemiology, "Study Links Depression and Alcohol Problems," Washington Post Health, Dec. 16, 1997}

Depression and Alcohol Problems Go Together

When alcohol wears off, you will be more depressed than ever.
{Ann Landers' to readers, Dec. 5, 1993, as well as many other medical sources}

Depression and alcohol problems often go together, but the evidence suggests that in men alcohol use preceded the depression, whereas in women the depression precedes the alcohol use.
{American Journal of Epidemiology, "Study Links Depression and Alcohol Problems," Washington Post Health, Dec. 16, 1997}

"Three recent studies document that consumption of processed foods increase odds of depression, and not only that, but those high protein, high fat diets (high in animal products) are also linked with more depression....."

I know for a fact that that is a blatant lie.  Four years ago I was diagnosed Type II diabetic and took classes at my clinic who taught us to control or reduce our diabetes with a high protein, unlimited fat, low carbohydrate (15 per meal - 45 per day total) diet.  Since going on this diet I have lost weight, have increased energy, controlled my Type II with diet alone, and have felt better than I have in years.  Most all the other students that I took the classes with have experienced the same benefits.  There hasn't been even a hint of depression or PTSD since going on this diet and my lipid profile has improved as well.

The clinic who puts all of their Type IIs on this diet (which is many thousands of people) and has been researching diabetes since 1923 and it simply blows your statement all to pieces.

You are obviously posting in order to sell your book.