Diet tip: "Wait 20 minutes for seconds."

Reason this should work: "Food must move 22 feet through your intestines from your stomach to peptide YY cells — the switch that says you are sated."

That's very helpful. Not that I want to think about the location — somewhere in the long, twisted path through my intestines — of what was so recently in my mouth, but I've noticed the tendency to eat and then eat again. It seems to be easier to avoid eating all afternoon than to resist getting one more thing after dinner. The dessert impulse. Even after breakfast or lunch, there's this feeling of needing to eat again. So the idea is: Just wait 20 more minutes. If the science quoted above is accurate, the feeling will ebb. Tell yourself: I can have something more if I still want it 20 minutes from now. The meal you just ate will, by then, have arrived in your peptide YY cells (whatever that means).