Do Low Protein Diets Cause Overeating?

Something sure seems to.

Lots of calories going down the hatch.

From Knowable Magazine, May 1:

Like hungry locusts, humans can easily be tricked into overeating
Our bodies crave more food if we haven’t had enough protein, and this can lead to a vicious cycle — especially if we’re reaching for ultraprocessed instead of high-fiber whole foods

This story starts in an unusual place for an article about human nutrition: a cramped, humid and hot room somewhere in the Zoology building of the University of Oxford in England, filled with a couple hundred migratory locusts, each in its own plastic box.

It was there, in the late 1980s, that entomologists Stephen Simpson and David Raubenheimer began working together on a curious job: rearing these notoriously voracious insects, to try and find out whether they were picky eaters.

Every day, Simpson and Raubenheimer would weigh each locust and feed it precise amounts of powdered foods containing varying proportions of proteins and carbohydrates. To their surprise, the young scientists found that whatever food the insects were fed, they ended up eating almost exactly the same amount of protein.

In fact, locusts feeding on food that was low in protein ate so much extra in order to reach their protein target that they ended up overweight — not chubby on the outside, since their exoskeleton doesn’t allow for bulges, but chock-full of fat on the inside.

Inevitably, this made Simpson and Raubenheimer wonder whether something similar might be causing the documented rise in obesity among humans. Many studies had reported that even as our consumption of fats and carbohydrates increased, our consumption of protein did not.

Might it be that, like locusts, we are tricked into overeating, in our case by the irresistible, low-protein, ultraprocessed foods on the shelves of the stores where we do most of our foraging? That’s what Raubenheimer and Simpson, both now at the University of Sydney, argue in their recent book “Eat Like the Animals” and in an overview in the Annual Review of Nutrition.

Simpson took us through the reasoning and the data in an interview with Knowable Magazine. This conversation has been edited for length and clarity.

How does an entomologist end up studying nutrition in humans?

My interest in feeding behavior goes all the way back to my undergraduate years in Australia, where I was studying the food choices of sheep blowfly maggots, which are laid in the wool of sheep and eat the sheep alive. For my PhD, I took an opportunity at the University of London, England, to study appetite and food intake control in migratory locusts, which exist in two extreme forms — one solitary and one aggregating in swarms that create devastating plagues.

Since they had this reputation for being absolutely voracious, we surely did not expect them to have a lot of nuance in the way they control what they eat. But I started to explore whether they could sense the requirement for different nutrients and use it to regulate their intake. That led to experiments with artificial diets of different nutrient compositions, which showed that locusts have nutrient-specific appetites for protein and carbohydrate: Their food tastes differently to them depending on what they need, and that enables them to balance their diets.....

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