My friend Margaret Miles-Bramwell, who has died aged 76, was the founder and chair of the weight-loss organisation Slimming World.

At the age of 21, after struggling with her weight, she hit upon the idea of forming a local weight-loss club. She set up Slimming World in early 1969 with the help of a friend and neighbour in Alfreton in Derbyshire, and by the end of the year the business had grown to 25 groups across the county and neighbouring Nottinghamshire. Today it employs more than 500 people at its head office in Alfreton, supporting a franchisee network across the UK and Ireland of about 3,500 self-employed consultants who run its weight-loss groups.

Born in London and adopted soon after birth by Emma Selina and Samuel Birch, Margaret grew up in humble surroundings in South Normanton in Derbyshire. She had to leave the local grammar school when she became pregnant at 15 with her first child, Claire. She married Claire’s father, Roy Miles, in 1964.

Margaret then worked at various jobs, including stacking shelves at a Co-op store in Pinxton, managing a furniture shop, working as an office junior at an engineering company in Sutton-in-Ashfield, and then at the Alfreton branch of Ladbrokes betting shops – before setting up Slimming World, which she headed until her death.

Margaret was not your typical business leader; she was more like a respected elder in a big, close-knit family, and she steered her ship in the way she lived her life – with a generous spirit, passionate conviction, a wicked (and rebellious) sense of humour and a lot of love. Aside from running Slimming World, she set up its charity, Smiles, which has raised more than £30m.

Her achievements were recognised with an OBE in 2009.

Margaret’s autobiography, Wild Women Do (And They Don’t Regret It), was published in 2019.

Her marriage to Roy ended in divorce, and in 1996 she married Tony Whittaker. He died in 2021. She is survived by Claire and by two other children, Dominic and Ben, from her first marriage.