There's actually some science behind this diet. Potatoes are the highest scoring food on the satiety index. https://www.healthline.com/nutrition/15-incredibly-filling-f... Basically they're the most filling food per calorie. So if you subscribe to the idea that losing weight is mainly about how many calories you consume, a potato heavy diet should be effective. And an all potato diet, while monomaniacal, even more ef…
[1]: https://www.nytimes.com/1998/02/18/dining/the-minimalist-tak...