I had also thought they may have gone out for dinner after the architect meeting (posted this earlier) and thought they could estimate the TOD by undigested food in the stomach if in fact they did.
There is undoubtedly much more in the autopsy reports that has not been released.
This is an informative link...
Estimating the Time Of Death in Practical Homicide Investigations
http://www.practicalhomicide.com/Research/LOmar2007.htm
Various ingested food materials remain within the stomach for variable periods of time, depending on the nature and size of the meal. It has been determined through extensive research that under ordinary circumstances the stomach empties its contents four to 6 hours after a meal. If the stomach, at autopsy, is found to be filled with food, and digestion of the contents not extensive, it is reasonable to assume that death followed shortly after the meal. If the stomach is entirely empty, death probably took place at least 4 to 6 hours after the last meal. If the small intestine is also empty, the probability is that death took place at least 12 or more hours after the last meal. In certain cases the medical examiner will be able to determine the type of food, which still remains in the stomach, if matched with the last known meal. This can help establish a time period.
(Just noticed deugirtni posted this link too. That's what happens when I read the thread backwards trying to catch up!)