"What Did You Eat Yesterday?" centers on the daily lives of Shiro Kakei, a middle-aged, frugal, and meticulous lawyer, and his partner Kenji Yabuki, a cheerful and easygoing hairdresser. The series explores their domestic life as a gay couple in contemporary Tokyo, with a particular focus on their shared meals and the role food plays in their relationship. Shiro, who is deeply conscious of budgeting, takes pride in preparing affordable yet delicious meals, often incorporating seasonal ingredients and practical cooking tips. Kenji, on the other hand, enjoys Shiro’s cooking and provides emotional support, balancing Shiro’s sometimes rigid personality.

The narrative unfolds through episodic chapters, each typically revolving around a specific meal or culinary theme. These meals often serve as a backdrop to explore the couple’s interactions with friends, family, and colleagues, as well as broader societal issues such as workplace dynamics, aging, and the challenges faced by LGBTQ+ individuals in Japan. Shiro’s reserved nature contrasts with Kenji’s openness, creating a dynamic that highlights both the joys and complexities of their relationship. The series also delves into Shiro’s past, including his struggles with coming out and maintaining a professional image, while Kenji’s more carefree attitude provides a counterpoint to Shiro’s anxieties.

Supporting characters, such as Shiro’s colleagues and Kenji’s clients, add depth to the story, offering glimpses into the couple’s social world and the ways they navigate their identities in different contexts. The manga balances lighthearted moments with more introspective themes, using food as a lens to examine intimacy, communication, and the small, meaningful rituals that sustain a relationship. The detailed depictions of cooking processes and recipes are integral to the narrative, providing both practical insights and a metaphorical connection to the characters’ emotional lives. Through its focus on everyday experiences, the series presents a nuanced portrayal of a long-term relationship, emphasizing the quiet, sustaining power of shared meals and mutual understanding.