Watching the Thin

I was on a business trip in Philadelphia with my boss...about 5' 1" and 100 lbs.  And we met with our primary client 5'2" and about 100 lbs also.  I ate with them regularly and realize that they really deserve their figures and that they eat like bandsters or more accurately the band helps us eat like thin people:

1)  They ate slowly
2)  They ate protein
3)  They ate small portions
4)  They tasted delicious foods but they never over ate
5)  They drink lots of water but sip
6)  They do not drink water during meals