Never heard that before. I've found I feel less like eating meat as I've gotten older, but I'm not 65 yet!

The thing about depression and diet is that everyone's different, and I suspect most of us are not all the way one way or another on a particular spectrum such as "all beef", but rather some of this and some of that.

Serotonin gets short shrift in a very low carb diet which clearly works for some people just as they may have responded to a norepinephrine boosting anti-depressant; for others, it's an SSRI which would probably correspond to a higher carb diet or some other intervention. Or a combination.

It's maddening that depression is not investigated more in terms of diet and nutrition. I've found, for instance, that to be ok I seem to need more than an average amount of magnesium.