Some studies show potatoes are the most satiating food, so one theory is eating them makes it more pleasant to stop eating generally and keep calories low (exact opposite of sugar, which makes one crave more food).
"Susanna Holt of the University of Sydney Australia did a research experiment in 1995 to compare the effects of different foods on short-term satiety and appetite levels. She prepared 240 cals portions of 38 different foods...The satiety index score she assigned to the potato was 323. No other food was even close. The second closest food was “ling fish” which scored 225."
https://scottabelfitness.com/potato-and-the-satiety-index/
"Susanna Holt of the University of Sydney Australia did a research experiment in 1995 to compare the effects of different foods on short-term satiety and appetite levels. She prepared 240 cals portions of 38 different foods...The satiety index score she assigned to the potato was 323. No other food was even close. The second closest food was “ling fish” which scored 225." https://scottabelfitness.com/potato-and-the-satiety-index/