.  But you
> have to choose your energy sources carefully to be an nutrient-dense as
> possible.  I think that would mean lean meats, berries, nuts,

but, you neglect to mention mineral- and vitamin-dense herbs which mostly
contain very few calories. if u made a fatty meat broth and threw in a dozen
suitable herbs I'm sure you could get the ful complement of nutrients for
1000 calories.

andrew