Tracy Nduati, 30, says she hopes to instil confidence in plus-size women in Africa, after winning the first edition of Miss Kenya Plus Size World, BBC Swahili reports.
The competition initially attracted 150 competitors and 20 made it to Saturday's final that saw Ms Nduati take the crown.
An elated Ms Nduati, who weighs 20 stone (130kg), spoke of the challenges plus-size women face and the stigma they have to deal with.
She described how in Kenya she is forced to pay double the amount for a bus fare, as she is accused of occupying "lots of space". Other competitors related similar stories.
Ms Nduati also said how her former boyfriend told her that he was ashamed to be seen with her because of her size, and would prefer her to stay at home and do chores.
She will now represent Kenya at an international competition in the US next month.
Earlier this year, Mariam Namukasa entered the Miss Curvy Uganda competition, watch her story: