Protein intake is stable across different diets

What I'm reading: An interview in Knowable Magazine with Stephen Simpson. Simpson is a former entomologist — somebody who studies insects — turned nutrition researcher. It's a curious career path that's led him to unique discoveries about diet, obesity, and longevity.

The big discovery: Simpson started by feeding cidadas a range of different diets, some higher in protein, some lower. He noticed the cicadas were eating to get their fill of protein. If there was less protein in the diet, they would eat more calories overall until they got to the required level of protein. With more protein in the diet, the cicadas would eat fewer total calories.

Stupid cicadas, but what about us? Simpson then took his research to mice, cats, dogs, fish, free-ranging primates, and finally, to domesticated primates also known as humans. The results were consistent:

• Protein consumption was stable across different diets

• Total calorie intake varied widely, depending on the quantity of food needed to obtain protein

So what does this mean for you specifically? Simpson is not advocating for a high-protein diet (that comes with its own costs, particularly for longevity). Rather, as Simpson puts it, “"ultraprocessed foods have been designed to hack our biology."

For example, barbecue-flavored potato chips are engineered to take advantage of our craving for savory protein. But those tempting chips actually contain very little protein, and quite a lot of calories in the form of carbs and fat. Eat one bag of chips, and you will just want to eat a second bag — you can never get your fill.

The basic conclusion of Simpson's work will likely be familiar: Avoid ultraprocessed foods. Instead, eat a diversity of whole foods, and make sure to get an adequate amount of protein. On the other hand, if you want more nuanced diet advice, particularly in relation to the protein trade-off of lifespan versus reproductive health, the interview with Simpson is worth a read.