Several years back, some guy on here made a table of similar dimensions and it weighed 450 lbs. As far as I am concerned, that is plain insanity. I see no point in it. You can make the edge 4" thick if you like that 'look', but not necessary to do that in the rest of the table. The dimensional stability of the timbers will affect how tight the joints will remain and this itself can be less than ideal for food service and could pose a health risk.
Unless you are using timber and post construction, this could also be a major safety hazard. Thicker is not always stronger. Structures can collapse under their own weight if not well thought out.
Tony B Retired woodworker, among other things.
"Strive for excellence and settle for completion" Tony B