"... a Reese’s peanut butter cup gave her such a rush that it was... 'like an orgasm of pleasure in my brain.' Now... 'It’s just peanut butter and chocolate. What’s the big deal?'"

A bariatric surgeon tells us about one of his patients, in a NYT article (by Gina Kolata) that takes the position that the weight loss after the surgery is not due simply to the reduction in the size of the stomach. We're told that "scientists have discovered that it actually causes profound changes in patients’ physiology, altering the activity of thousands of genes in the human body as well as the complex hormonal signaling from the gut to the brain."

I can't help feeling skeptical. "Scientists" — what scientists? There's a huge financial interest in performing all this surgery, and there's a lot of pressure to reduce medical spending. Doesn't that skew the research?

It's a long article, but the actual science part is minimized. Here's the most technical part addressing my skepticism:

It has become clear that bariatric surgery changes the entire setting of a complex, interlocking system. There is no one place to tweak it. To show what is involved, [Dr. Lee Kaplan, an obesity researcher at Massachusetts General Hospital] reports that surgery immediately alters the activity of more than 5,000 of the 22,000 genes in the human body.

“You have to think of it as a whole network of activity,” Dr. Kaplan said. It’s a network that responds to the environment as well as to genes, he added. Today’s environment probably pushed that network into a state that increased the set point for many people: Their brains insist on a certain amount of body fat and resist diets meant to bring them to a lower weight and keep them there.

“Surgery moves the network back,” Dr. Kaplan said.

But surgery only alters the intestinal tract. That tells you, Dr. Kaplan says, that there are whole classes of signals coming from the gut and going to the brain and that they interact to control hunger, satiety, how quickly calories are burned and how much fat is on the body.

One major hormonal change is in bile acids. There are more than 100 varieties of these hormones, which help regulate metabolism and digest foods. They send out broad signals, like television signals, to any cells in the body with the capability to respond. And the relative proportions of the different bile acids change immediately with surgery.

Neurons, which signal specific targets in the brain, change, too. And so do white blood cells of the immune system that send their own signals. Although they are usually thought of as fighting disease, white blood cells play a major role in setting a person’s weight by, among other things, helping control metabolism.

The gut’s microbiome — the thousands of strains of bacteria in the intestinal tract — changes, too, immediately and permanently. Its interaction with the rest of the network is part of the weight-loss picture.

But for bariatric surgery to work, the setting in the brain that determines how much fat a person will have — what Dr. Kaplan refers to as the body’s thermostat for fat — must have been set too high, not broken.

A few rare genetic mutations break the thermostat. People with those mutations have no internal controls on their fat and grow enormously obese. Bariatric surgery has no effect on them. People like Jessica and Keith, whose thermostats were mis-set, reach a point at which they are obese but their weight holds steady without any effort on their part. Surgery can lower their thermostat’s setting.

I invite you to critique that as science. To my eye, there's a theory — the gut must affect the brain — and a metaphor — the thermostat — superimposed on the anecdotal experience of the surgery working for 2 patients.

And someone decided to title the story: "After Weight-Loss Surgery, a Year of Joys and Disappointments/Even as the pounds fell away and their health improved, two patients contended with the feeling that life hadn’t changed as much as they’d hoped."

That utterly eclipses the scientific question of why the surgery works — whether it's mostly or only because the patient can no longer fit much food into the stomach.

The article does focus on the psychological state of the 2 patients, and the stress — in the headline and the text of the article — is on the lack of change in their psychology, in their brains: They felt "that life hadn’t changed as much as they’d hoped." So where does that leave the scientific explanation which is about how profoundly the brain has changed physiologically?

Something's missing, I think.

I'd like to see a lot more detail on the cost of the surgery in relation to the success, the economics of the research, and the politics of fighting for acceptance of expensive treatments for conditions that many people perceive as belonging within the realm of individual responsibility.

Speaking of article titles, I've wandered far from my own post title, so let me end by saying "orgasm" — the word that jumped out at me — is a metaphor in that quote about Reese's peanut butter cups. The doctor used it to grab us. Grab us by the pussy, one might say. Grab is another metaphor. We love the concreteness of these metaphors. Metaphors grab us. Not really. Just metaphorically.

Metaphor is poetry, not science. When surgeons come at me with metaphor, it triggers my bullshit detector. That's this thing in my brain. Next to the thermostat.

Don't bullshit me, surgeon. You need to cut right to the core.