I live on an estate with a lot of families in poverty, myself included in that. And there's lots of reasons people are struggling round here, some of them are as follows;
Unstable jobs or work contracts. This is not necessarily due to COVID either but a lot of people round here are either on zero hour contracts or are self employed (often they should be classed as employed but it's a sneaky way for companies to use them and get rid when it suits)
Money is just that tight that it only takes one problem to cause long lasting effects on the household. Like the car breaking down, a household repair (if own house), a device, laptop or printer needed for hone study needing to be bought, a fridge or cooker needing replacing. This can also cause a family to fall into a debt trap that just spirals out of control.
The benefit cap meaning you have to use your other benefits to top up your rent (this is a big problem for me) as housing benefit isn't allowed to cover it
The 2 child limit cap
The cost of living going up much higher and faster than wage or benefit increases.
Food prices have definitely gone up, I have noticed my bills rise.
Food is often bought with whatever is left after all rent and bills have been paid