How many people in the UK are in ‘hunger and hardship’?

Families in the hunger and hardship category are typically on low incomes, have little or no savings and may also have debts. Photograph: Jonathan Brady/PA

A study by the UK’s biggest food bank network, Trussell, estimates one in seven of the UK population are struggling in a category of deep poverty it calls “hunger and hardship”. But what does it mean, who is affected by it, and why?

What is hunger and hardship?