"Oishiku Naritai!" centers on the life of Yuki, a high school student who struggles with self-esteem due to her weight and appearance. After being rejected by her crush, Yuki decides to transform herself by losing weight and improving her physical appearance. She embarks on a journey of self-improvement, adopting a strict diet and exercise regimen. Along the way, Yuki encounters various challenges, including societal pressures, body image issues, and the emotional toll of her transformation.

The narrative explores Yuki's relationships with those around her, including her supportive best friend, Miki, and her childhood friend, Riku, who harbors feelings for her. As Yuki progresses in her journey, she begins to question the true meaning of beauty and self-worth, realizing that her initial motivations may have been superficial. The story delves into themes of self-acceptance, personal growth, and the impact of societal beauty standards on individuals.

Yuki's transformation is not just physical but also emotional, as she learns to value herself beyond her appearance. The manga portrays her struggles with setbacks, moments of doubt, and the realization that true happiness comes from within. Through her interactions with others and her own introspection, Yuki gradually develops a healthier relationship with her body and self-image.

The series balances moments of humor, drama, and introspection, offering a nuanced portrayal of its protagonist's journey. It addresses the complexities of body image and self-esteem in a relatable and empathetic manner, making it a compelling read for those interested in stories about personal growth and self-discovery.