I used to take Xenical (a fat blocking prescription medicine in the form of blue capsules) a couple of years ago and it is supposed to block your body from absorbing about 30% of the fat you eat from foods.
Well the effect comes with having fatty or oily stools. You will see orange or yellow spots of grease in the toilet with your bowel movements because that is the fat that has been stopped from being absorbed by the Xenical in your intestines. All the work takes place in the intestines so it isn't chemical in reaction.
When I read your post, your experience reminded me of that and I am thinking either:
-that you could have a very high metabolism and eating a mostly fat diet could make you excrete excess fat in your stools...which is what you described. (are you male btw?)
-or that that maltitol in the candy bars you ate have a Xenical effect...because the gas and bloating that comes with consuming maltitol is caused by the holding of water in the intestines so perhaps it can block the digestion of fat somewhat... I have not read this in relation to maltitol...but who knows. Maybe eating a lot of fat with maltitol acts like Xenical...because maltitol does have a laxative effect.
With Xencial the more fat you eat the more you will have messy oily stools which is why when people take xenical they wisely choose not to overdo it on the fat content in their food therefore it is supposed to work with a low fat diet. Taking Xenical on Atkins for example would NOT be a good idea... *laughing* because the idea of not to be low fat or to strive to be low fat
I eat low carb bars with maltitol in it and have gotten the bloated, gaseous feeling but never the oily stools...just discomfort in my abdomen... but it sounds like either of the above I mentioned could be the issue. I would go to a doctor and talk to them about this to see what they say just to get a professional POV.
Just some thoughts.