Transdermal Nutrition

Los is (as usual) right about how the packaging of the TDNS looks. It is
more like a patch. 

As anyone who knows silicon will tell, chips take up a small chunk of
the
real estate we probably imagine - the big thing in your PC is probably
mostly plastic and exists mostly to provide interconnects to N separate
pins
or pads. The chip itself is usually quite small.

The TDNS chips are pretty small and the patch would contain "a microchip
that would interact with the sensors to assess a soldier's metabolic
needs."
Then the stuff would be micrometer'd out into the bloodstream. 

As for hunger...
"Chemicals which fool a hungry person's brain into believing his or her
stomach is full... could also be injected through the patch..."

The Jane's article suggests these would be used for "high tempo
operations".

Tom.