Potato diet finished: what I learned

I experienced good weight loss results, about 10 pounds (226.2 on April 5 → 216.6 on May 6). I also got deeply, deeply sick of eating potatoes about three weeks in, such that the last week was a major struggle. In truth, I didn't make it a full 30 days, but I'm not agonizing about that.

I have now transitioned to a “whole foods” diet, which mostly consists of vegetables, fruit, fish, and olive oil. It's not a pure whole foods diet because I have included some non-whole foods in it, namely cheese and yogurt, as well as a pea protein powder that I like; this also isn't a Mediterranean diet because I'm still open to eating potatoes. It might be easier to conceptualize this diet in terms of what I'm avoiding, namely: anything artificial or ultra processed, eggs and most meat, bread, pasta, and other flour-based foods, and anything with added sugar especially my greatest weakness: ice cream. In all cases my diet is not perfect; I am aiming for 80/20 adherence, focusing on high adherence at home and alone while allowing some indulgence if going out with other people, which is uncommon for me anyway so nbd.

Because it is so much more varied and less boring than potatoes, I have no reason to think that I can't sustain this diet indefinitely and continue to lose weight at a gradual rate. Weight loss is still very much my headline goal—I aim to lose at least 20 more pounds—but I have no particular need to get there with the same haste with which I just lost the first 10 pounds, as nice as that would be. More research is required. I'm still tracking my weight daily and calculating my bodyfat percentage weekly using a measuring tape method (I actually bought calipers too but haven't figured out how to use them properly yet).

In addition to weight, a major focus of this diet experiment was digestive health. My digestion does seem to be much better than it was a month ago, although certain “rich” foods I've had from restaurants in the past week gave me profound gas in a way that the ordinary whole foods I eat the rest of the time do not. It is hard to pinpoint a specific ingredient here—obvious candidates include (cooked) onion, butter, cream, and certain seasonings. There might also be some complex combination that gives me gas. I will be keeping an eye on this. As for bowel transit times, they are slow on the potato diet and have sped up a lot since reintroducing other foods.

To sum up, I'm pretty sure the potato diet works primarily because it's a calorie restriction diet. That said, potatoes seem to have some special properties that make them well-suited to rapid weight loss through calorie restriction. In particular, I learned that they contain potato protease inhibitor II (PI2), a protein that seems to reduce appetite for whatever reason. Anecdotally, potatoes do seem to have a very distinctive appetite suppression effect. If I didn't know about PI2, I would have attributed this to what felt to me like blood sugar stabilization through starch metabolism, but alas I did not measure my blood sugar during the diet.

In the final analysis, I would recommend this diet to anyone who wants to kick start some weight loss and break bad eating habits in order to replace them with sustainable healthier ones. You could probably do it for as long as you like (with appropriate vitamin supplementation to counteract the limitations of potatoes) but a month feels like a realistic starting point for most people. It is challenging and eye-opening, plus you'll save a bunch of money on groceries!