"hunger resistant"

It is an indirect approach and it is related to biology and thermoregulation but you can consider the term ectotherm.

Ectothermic organisms can slow down their metabolisms (some can even stop) and they can endure hunger for a long time unlike endotherms.

An ectotherm is an organism in which internal physiological sources of heat are of relatively small or quite negligible importance in controlling body temperature.

Such organisms rely on environmental heat sources, which permits them to operate at very economical metabolic rates.

Endotherms cannot in general afford such long periods without food, but suitably adapted ectotherms can wait without expending much energy.

^{http://en.wikipedia.org/wiki/Ectotherm}

^{Note: Most mammals, including humans, as well as most birds are endothermic homeotherms, while most fish, invertibrates, reptiles, and amphibians are ectothermic poikilotherms. http://minerva.union.edu/linthicw/endo.htm}

Also related is subsistence or subsistence lifestyle. [or subsistence diet which is directly related with food]

subsistence noun

means of subsisting: as
a : the minimum (as of food and shelter) necessary to support life
b : a source or means of obtaining the necessities of life

[merriam-webster]

People who practice subsistence living survive with minimal resources which is mostly related to eating barely enough food and these people endure hunger. One example can be observed in Alaskan native culture.

Eating a subsistence diet in temperate climates is neither pleasant nor the preference of anyone who enjoys a varied and plentiful diet, and it is even more difficult in circumpolar/arctic regions. However, it is often more necessary. A person who lives on such a diet eats barely enough to sustain life, and no one is likely to choose it unless there is not other choice.

Alaskans have practiced subsistence living for thousands of years, and it is a custom that involves ancient traditions.

^{http://www.inchr.com/what-is-a-subsistence-diet/}

A passage regarding subsistence social value and subsistence agriculture:

Subsistence and Economic Development By Ronald E. Seavoy

How about low metabolism or slow digestion?