I agree with the single servings at home only. No full pies, full cakes, or multi pack cookies. I also agree with the idea about drinking lots of beverages. And if you need more sweet, another idea is to have tea or coffee with plenty of milk and sugar. Or hot cocoa or chocolate milk. Also, things like yogurt can be good choices, rather than ice cream. I find dairy products very filling and satisfying, and rarely eat/drink THAT much, with the exception of ice cream.

Add on: Another idea if you buy large portions of a dessert or cakey thing is to freeze a lot of it, in smaller portions. Bluebicycle's idea below works with this. I don't know if the chocolate pie would work well (if it is pudding or custard-like, or fruit pies), but many things do, especially anything cake-like. Quite a while back I made blueberry muffins. Twelve is a lot to have around for just two people. So I froze 9 or 10 of them. I take two (only) out when I want one to defrost. The effort of defrosting deters me from having many.