WIL Weekly Review #24

Seed Oils, Prolactin, Brain Development and more...

This is my free weekly newsletter covering 5 interesting points from the week. Subscribe (if you haven’t already) if you’d like to get it in your inbox each week!

1. Same calories, more obesity: Seed oils making us fat?

Zero Acre Farms points out that despite calorie intake remaining largely the same from 1975 to 2013 in Japan, obesity nearly quadrupled from 1% to over 3.5% in that same time frame. They write that “Japan’s vegetable oil intake doubled and since 1950 it has increased 13-fold.”

I couldn’t find their source for that last claim, but according to MAFF (Ministry of Agriculture, Forestry and Fisheries of Japan) data per Japan Oilseed Processors Association, the per-person intake of vegetable oil from 1960 went from about 3.5 kilograms per year to about 13.5 kilograms per year in 2000.

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2. Switching to Chicken is lowering Men’s Fertility?

In response to this point by Dr. Steven Belknap:

“In the 1970s, we ate 3X more beef than chicken (as estimated from availability). Today, we eat more chicken than beef & what beef we do eat is lower in saturated fat,”

Dr. Chris Masterjohn tweeted:

And this, my friends, explains why male fertility is on the decline. Zinc, zinc, zinc, zinc, zinc. Beef has twice as much zinc as chicken. The average male ejaculation contains 1 mg of Zn, which requires 3 mg of dietary Zn to compensate, found in 2.5 ounces of beef.

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3. Does happy music raise testosterone?🤷‍♂️

Image from tufts.edu

Prolactin in men is thought to be a hormone that aims to evoke more calm, caring and “nice” paternal behaviors in new fathers. Further, “elevated parental prolactin levels after childbirth decrease the parents’ libidos so that they invest more in parental care than in fertility behavior.” Prolactin lowers luteinizing hormone which in turn lowers testosterone. It’s also responsible for the refractory period men experience just after sex. To illustrate that, cabergoline, a medication designed to treat excessive prolactin, shortens the refractory period and increases libido. (This is definitely not a recommendation… cabergoline, a dopamine agonist can elicit addictive behavior like binge eating and compulsive buying.)

In 2011 David Huron proposed that elevated prolactin levels would lead to increased enjoyment of sad music. A 2019 paper found that sad music did not have an effect on prolactin and the enjoyment of sad music wasn’t related to prolactin levels. In 2022, David Huron released a paper titled The Prolactin Theory of Sad-Music Enjoyment is Wrong.

However, that 2019 paper found that nominally happy music decreases prolactin. Though, it might not work for you if you don’t like happy music:

“Instead, a significant decrease in PRL was observed when listening to nominally happy music. The decrease in PRL concentrations for the happy music condition was found to be driven predominantly by the happy-music likers.”

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4. Testosterone suppression will crush brain development

A paper titled Brain Maturation, Cognition and Voice Pattern in a Gender Dysphoria Case under Pubertal Suppression performed an evaluation of a puberty blockers’ effects on a pubertal transgender girl. The puberty blocker was a GnRH analog that suppresses testosterone.

Global IQ dropped from 80 to 71 in just 17 months. At the end of 28 months of 'treatment' with puberty blockers, every single measure of cognition (Comprehension, Perceptual Reasoning, Working Memory, Processing speed) was worse than before starting the puberty blockers.

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5. Mate Choice Copying

The good news and bad news for women is that it’s very simple to be attractive to a man. The good news and bad news for men is that being attractive to a woman is more complex. She could be attracted to you because you’re the right mix of: health, wealth, status, humor & charisma, height, but she may also be attracted to you because she thinks other women are attracted to you.

Dr. David Buss explains in his textbook Evolutionary Psychology that women use “social information” to determine how attractive a man is.

Two studies found that women judged a man to be more attractive when he was surrounded by women compared to when he was standing alone (Dunn & Doria, 2010; Hill & Buss, 2008a). Two other studies discovered a mate copying effect only when the man being evaluated was paired with a physically attractive woman (Little, Burriss, Jones, DeBruine, & Caldwell, 2008; Waynforth, 2007) … another revealed that the effect is strongest when women blieve that the man is actually partnered with the woman and infer that he possesses unobservable qualities that women prize in a potential mate. (Hodeheffer et al., 2016)

This makes sense since the formula for a man to be attractive enough for a woman to consider as a partner is much more complex than the man’s formula for evaluating women. So, a woman may unconsciously bypass the tricky process of evaluating the man’s traits on the whole by using other women’s attraction to him as a rule of thumb that he’s probably a pretty good catch.

This is likely why many men have had the frustrating experience in high school or college where a woman they were attracted to suddenly displays interest in him after he gets a girlfriend.