Escolar, the snake mackerel with gempylotoxins.

Yum! Last night, I ate a type of fish I'd never heard of before, and if I'd had internet access in the restaurant and looked it up, I would never have ordered it:

What gives these fish their desirable taste is actually a component similar to those used to produce Olestra, the fake fat found in some snack foods: a fatty substance called wax esters, in this case, gempylotoxins. Humans cannot digest these wax esters because they lack the enzymes necessary to break the large molecules into smaller, absorbable components.

Harold McGee, the author of ''On Food and Cooking'' (Scribner, 1984), described the process elegantly in a paper he delivered at the 1997 Oxford Symposium on Food and Cookery: ''The wax esters therefore pass intact, their lubricating properties undiminished, from the small intestine into the colon, where a sufficient quantity will defeat our normal control over the ultimate disposition of food residues.''

So it's the Olestra of fish? Well, I was perfectly fine and the fish was delicious.