The Ministry of Thin_FINALAlice and I are walking down the aisle marked Dairy. I take four small tubs of Total 0% Greek yogurt, a couple of raspberry-flavor Müller Lights. I add a four-pack of vanilla probiotic Activias, then a two-pint carton of skim milk. My sister grimaces at the red-top milk—“Skim? That stuff looks like dirty water.” I nod cheerfully, “I know, tastes like it too.” We turn the corner into the aisle marked Meat, where it’s Al’s turn to stock up: bacon, chicken, and some kind of fish.

At the checkout line, we look at our baskets: butter, bacon, and eggs in hers; muesli, pita bread, Greek yogurt in mine. I also have apples, broccoli, bananas; Al has sparkling water, salmon, avocado.

See what she’s doing, and see what I’m doing? Without even thinking about it, we both have our forbidden foods—or, if not entirely forbidden, substances we steer clear of. Al never buys coffee or wine, although she will have the occasional cappuccino or glass of wine when she’s out. I literally don’t go near butter, and I wouldn’t know how to cook any of the meat she buys. Odder than her wariness of caffeine, and my strict vegetarianism, is our avoidance of whole food groups. I don’t do fat; she doesn’t do carbs. A few decades ago these might have seemed strange rules to follow, but these days they’re pretty normal. In the twenty-first century most women police their diets in some way.