Malnutrition is responsible for nearly half of all deaths in children under five across the world according to a new report published in the Lancet.
Poor breastfeeding practices and deficiencies of vitamins and minerals also account for 100-million underweight children - mainly in Asia or Africa.
Tearfund supporter Joy Blundell from New Life Church in Lincoln has told Premier's Victoria Laurence it's the reason why she's going to the 'Big If' rally in London's Hyde over the weekend: