@kiwi_outdoors  I tend to agree but it really depends on the calorie density of the food you carry. 

The general rule of thumb is 2# a day which assuming an average of 100 cal/oz gives around 3200 cal per day...which is about the active requirement of a 15-35 year old active male. Also it is commonly reported that people don't need that much the first week which probably builds in the safety margin for a 2 week trip.  You mileage may vary of course. 

By that rule 14 days means carrying 28#

100cal/oz is a pretty good guesstimate average for the stuff people generally take backpacking.   If you can design a diet the ingredients of which give 200 cal/oz then you can carry half as much food.  I probably should have made that point explicit. 

It may be difficult to design a palatable and effective diet with 200 cal/oz ingredients but it is certainly possible to do better that 100 cal/oz if you plan it out.