I have been researching "eat slowly" and "eating slowly" for losing weight; the explanation of how and why it works is so obvious:
The digestive and hormonal process (Doctors can explain this better, I am an Engineer) that sends the signal to the "sensor"in the brain saying: "You are not hungry anymore, do not overeat" takes an estimated 20 minutes on average.
We eat in about 7 minutes, that means we will always be hungry after we eat and go for seconds.
We are unconsciouly training ourselves to ask for more in the first serving, after all our experience tells us that we are always hungry after finishing our meal aren't we?
Do not feel deprived, eat slowly and enjoy.