Title garnered mixed reviews from critics, who thought its tracks had potential for commercial success, but considered the lyrics too repetitive and questioned Trainor's musicality.

After her father encouraged her to pursue her musical interests, she independently released three albums from material she had written, recorded, performed, and produced, between the ages 15 and 17.

[1][2] Though Trainor had been offered a full scholarship to the Berklee College of Music, she decided to pursue her songwriting career and signed with Big Yellow Dog in 2012.

[5][6] Disenchanted with the electronic dance music that populated Top 40 radio, he had wished to create a "'50s-sounding record of doo-wop-inspired pop" for three years, but could not find any artist that shared his interest.

[7][8] Trainor, who had been introduced to doo-wop by her father at a young age, found it to be "the catchiest stuff" and wanted to create something reminiscent of The Chordettes's 1958 single "Lollipop".

[9] Kadish shared his idea with Trainor after the two bonded over Jimmy Soul's 1963 song "If You Wanna Be Happy", and they decided to create an extended play (EP) with the same sound, "just for fun".

[7] Trainor moved to Nashville in November 2013 and they co-wrote the song "All About That Bass", pitching it to different record labels, all of which rejected it due to its doo-wop pop sound as synth-pop was more popular at the time.

[5] The label briefly suggested that Trainor work with other producers, such as Pharrell Williams or Timbaland, but she insisted on continuing with Kadish: "Kevin's my guy".

"[7] Upon its release as Trainor's debut single on June 30, 2014,[11] "All About That Bass" reached number one in 58 countries and sold 11 million units worldwide.

[6][18] Title comprises songs inspired by 1950s doo-wop music that "straddle the line between modern R&B and melodic pop", according to AllMusic's Matt Collar.

[19] Jon Dolan of Rolling Stone stated that the EP combines "trickle-down Beyoncé empowerment themes" and "sugary doo-wop and girl-group melodies".

[26] The title track is a doo-wop song with Caribbean music influences and a ska-inflected bridge,[30][23][29] which blends the horn and ukulele folk-pop with island percussion instrumentation and a programmed beat, and also incorporates handclaps and modern sound effects.

[37][38] It opens with a stylus sound on a damaged vinyl and transitions into retro ukulele instrumentation,[1] further incorporating brisk piano, buoyant brass, and a drum track.

'"[1][2] Trainor and Kadish grew up as "chubby" kids,[30][40] and wrote the lyrics of "All About That Bass" as a call to embrace inner beauty, and promote positive body image and self-acceptance.

[20][46] "Dear Future Husband" is about chivalry and dating,[39][47] and lists the things a man needs to do to be Trainor's life partner, and win her adoration and dedication.

[20][31] Collar praised Trainor's vocals as "soulful, highly resonant," and catchy; he considered "Dear Future Husband" and "All About That Bass" irresistible.

Knoxville News Sentinel thought she showed crisp artistic vision on the EP but dubbed its tracks "sort-of sequels" of her debut single.

[31] Chris DeVille of Stereogum thought she could only outlast the success of "All About That Bass" if she found new topics to write about, and was disappointed that the lyrics of "Dear Future Husband" and the title track were interchangeable.