The Money Saving Expert founder said a “substantial” increase in funding was needed to help those who were worst hit by the surge in prices.
Mr Lewis told the BBC: “We are going to have to put money into the system or we are going to have an absolute poverty crisis, with people being unable to eat or dying because of the cold.”
His warning comes before energy regulator Ofgem is set to unveil the price cap hike for 15 million households on 7 February, the Mirror reports.
Mr Lewis suggested one option open to cut costs would be to axe the 5 per cent VAT on energy costs, which could save £100 off bills.
But he called for action to help those most severely affected, including a targeted version of the cap which would freeze bills for vulnerable families.
Mr Lewis told BBC’s Radio 4’s Today programme: “We absolutely know that we need a substantial increase in the billions of pounds of funding to vulnerable people and people on low incomes or it is no exaggeration to say some will have to choose between heating and eating, and that is not appropriate in one of the world’s richest economies and a civilised nation.”
He added: “We are going to have to give people that money and it’s going to have to come in the first instance from the Exchequer.
“How the Exchequer pays for that, whether that’s through a windfall tax, whether that’s through increasing general taxation, whether that’s increasing government debt, I will leave to the economists.”
He advised expanding the criteria for the £140 Warm Homes Discount to include those eligible for Universal Credit.
A report from think tank the Resolution Foundation revealed millions of families in England will experience fuel poverty overnight when bills rise in April. The organisation predicted the number of households who will find energy unaffordable will treble to 6.3 million.
The former head of Ofgem, Dermot Nolan, said the energy crisis caused by rising wholesale gas prices was a “worldwide phenomenon”.
However, the regulator has been criticised for failing to deal with problems specific to the UK over many years.
They include criticism over the dozens of energy suppliers that have shut down due to the surge in costs, leaving households to pick up the huge bill.
Mr Nolan said: “We have got a number of things wrong but fundamentally it is not our fault that gas prices have risen internationally.”