Nowadays we think it is normal and right to eat until you are full, but many cultures specifically advise stopping well before that point is reached. The Japanese have a saying—hara hachi bu—counseling people to stop eating when they are 80 percent full. The Ayurvedic tradition in India advises eating until you are 75 percent full; the Chinese specify 70 percent, and the prophet Muhammad described a full belly as one that contained ⅓ food and ⅓ liquid—and ⅓ air, i.e., nothing. (Note the relatively narrow range specified in all this advice: somewhere between 67 and 80 percent of capacity. Take your pick.) There’s also a German expression that says: “You need to tie off the sack before it gets completely full.” And how many of us have grand-parents who talk of “leaving the table a little bit hungry”? Here again the French may have something to teach us. To say “I’m hungry” in French you say “J’ai faim”—“I have hunger”—and when you are finished, you do not say that you are full, but “Je n’ai plus faim”—“I have no more hunger.”