Which did actualy happen - but in Austria Hungary where all the pigs were killed so they wouldn't consume grain, but the subsequent shortage of meat was worse than the shortage of grain would have been, because grain doesn't supply protein in the diet.
According to he link hjaco supplied above, Belgians wee starving in a similar manner to Germans..possibly even worse....but the Germans (naturally IMO) were unwilling to let in supplies of food for Belgian civilians supervised by neutrals - having the conquered nation being better fed than the conquerers was unacceptable (possibly short sighted tho - imported food could probably have been substituted for Belgian grown food that could then have been sent to Germany?)
the article notes that the German army was pretty much a looting machine in northern France where it ruled, with no thought given to future production, but het occupation Govt in Belgium was more reasonable, so I would expect the German Govt of hte Brest-Litovsk territories to have been less ruthless than the army too.
In search of some material regarding requisitioning of grain and livestock in occupied territories I also found some more elaborate descriptions of the vast destruction of mines in northern France.
After reading about the consequences to food, meat and diary production in France i cede any reservations about the current depletion of food resources.
Official summary to the Versailles Treaty:
"The Saar: In compensation for the destruction of coal mines for northern France and as payment on account of reparation, Germany cedes to France full ownership of the coal mines of the Saar basin with their subsidiaries, accessories, and facilities."
See in particular page 10, 11 & 19:
"In summer of 1921 production of all mines in northern France and Pas-de-Calais area was restored to 1/4 of their prewar levels"
Abstract consideration of Franco-German conflict from an economic and resource point of view.