> The diet worked — people lost 10.6 lbs on average over only four weeks — and we had basically no idea why

I do fasting a lot. Doing diet for weight loss is a huge red flag. Human body gains and loses water very easily. Change of 10 lbs (in any direction) is rounding error, after changing a diet.

Major reason to do potato diet are health benefits. It decreases inflammation, and gives your gut chance to heal. It may improve sugar digestion, liver and so on. Basically any junk and toxins you eat normally, go away on potato only diet.

AFTER you become healthy, you may try to lose weight.