Thus far, pretty good. I could not swing 30 straight days of fasting though. I am eating normally (paleo + some cheese) for 1 day out of every 7-10. No odd feelings, and no performance decreases, although I suspect they might be hard to detect immediately. Pretty standard IF format and results. Eating window is a bit small, about 6:30 to 10-11, but glugging some olive oil along with 2 large meals seems to be covering me just fine, hardly feeling hungry.
Lost about 4lbs thus far, which was not my intent, but since it seems to have been fat loss, who can complain.