Kitazawa-kun wa A Class

Masashi Kitazawa, a second-year high school boy, hides a traumatic secret of being fat as a child! After a strenuous diet and strength-training regimen throughout junior high, Kitazawa has grown to become a handsome young man and he is content to lead an ordinary high school life, but....... Starting the new semester of the second year, Kitazawa finds himself in Class A, filled with the most popular and good-looking people in his grade. Moreover, he receives a secret invitation from the most beautiful girl in school, Ayame Yagyu......? This is a school comedy about the high-class beautiful people!

(Source: Weekly Shonen Magazine, translated)