What you ask, regarding the analysis of census data, is completely besides the point because it doesn't even fit the example in the essay.

You make a statement about the bell curve. Jennifer, the modern vegetarian, is not in the bell curve.

http://www.vegetariantimes.com/article/vegetarianism-in-amer... suggests that 10 percent of U.S., adults, or 22.8 million people, say they largely follow a vegetarian-inclined diet.

Even if it's 20%, that's still not near the center of the modern US diet. So already the essay isn't a strong match to modern culture.

I sure can say that someone is wrong about their memory, but in this case I'm saying that the OP's recollections don't fit the data. Even if true for the OP, it appears to be atypical.

You complain that I mention pulp sources. I've also mentioned diary entries. Every single entry is a "personal insight."

See http://diaries.markbartlett.net/diary58.html for another example. "We had fried chicken, mashed potatoes, salad, date nut bread and coffee for dinner." and "Mrs. Colburn gave us sack of green beans and Mrs. Burnett more green beans, onions and beets." (Some of that would have been canned, but some certainly eaten fresh.) "Mr. and Mrs. Kluckman and baby here tonight – brought green beans and cabbage."

Or http://melissa-ellison.tripod.com/id25.html from 1933, "July 9 We were all alone today. No one came. Very warm. We had string beans for dinner today." (They picked and canned the string beans the day before, so these were fresh beans.) "Sept 26 Very warm and sultry. We are again to have boiled bacon and swisschard for dinner today." "Nov 14 Cloudy and snowflurries. We had spare ribs and carrotts cooked together for dinner."

https://www.ashleighbrilliant.com/Diary%201951.%20America.ht... which is about a British man visiting the US in 1951: "For dinner I had fruit and soup and bread and broccoli & 2 huge lamb chops & Pepsi Cola & chocolate cake & milk.", "We had a fine lunch of meat, potatoes, vegetables, apple juice, raspberries & ice-cream." (It's entirely possible that the vegetables were canned or frozen. At some point though I don't think it makes a difference. Most of my vegetables now are frozen too.)

I'll make my point again. The author of the essay sets up a hypothetical "Betty" from 1958 in a situation which does not appear to be characteristic of the larger society. The OP - the one who linked to the essay - finds the description to be characteristic of the OP's own history. That doesn't mean that that OP's memory is a true reflection of the time.

You want me, I believe, to demonstrate somehow that the OP must not be correct. I am trying instead to show that the hypothetical Betty is likely not characteristic of the era, and given the well-known problems with human memory, I want something stronger than a childhood memory when the available "pulp" evidence so strongly shows a much wider variety of food dishes for that era.

This was absolutely the era before the War on Poverty, and before the Civil Rights era. The essay seems to exclude immigrant foods (fresh bok choi for Chinese dishes), regional foods (like Southern dishes with collard greens), etc. That's why I argue that it isn't representative of the 1950s, but only representative perhaps of the most culturally influential social groups of that era .. and the OP may also be a member of that group.