Ichinichi Sanshoku Zettai Tabetai

The earth has entered another ice age after civilization was wiped out by widespread flooding, and the remaining survivors must be self-sufficient. Yuki, a worthless NEET, is living with a young girl named Rikka, who is of weak constitution and always losing weight. She reluctantly gets a job to make sure that Rikka can have three delicious meals every day.

(Source: Kodansha, translated)

Included one-shot:
Volume 2: Uchuu no Laika