Citizens Advice Scotland (CAS) called for urgent government action as it revealed a 47% increase in food bank inquiries on its services.
It said it provided advice on emergency food providers 7,400 times in 2014/15.
The UK government said the report failed to recognise that poverty in Scotland was at a record low.
A spokeswoman for the Department for Work and Pensions said it spends Â£90bn a year on working-age benefits to help the most vulnerable in society.
The food bank statistics emerged in a new report - Living at the Sharp End - in which CAS researchers investigated the root cause of the trend.
The report revealed clients often arrived at citizens' advice bureaux hungry, having not eaten for days, and with no money for essentials.
A total of 71% told researchers they cut down on food when they were faced with a gap in their income.
The report also found the service was increasingly seeing people who had exhausted all forms of government support and whose only option was to go to a food bank.
The Scottish government is set to gain control of some aspects of welfare in September.
Scottish Secretary David Mundell is expected to sign off the transfer and timetable later this week.
The report's findings included a profile of the CAS clients who sought advice about food banks. It found that:
CAS head of policy and public affairs Susan McPhee, called for urgent government action to prevent people slipping through the safety net of social security.
"When reports like this have been published in the past, the standard reaction of the UK government has been to say that there is a support network in place that prevents people falling into destitution," she said.
"Our evidence today shows beyond dispute that this is simply not the case.
"If it were, there would be no need for food banks at all, yet Scottish CABs had to give food bank advice over 7,000 times last year, and our report shows that too many Scottish families are struggling in severe poverty."
The report found changes to the benefits system, low pay, insecure work and the rising cost of living contributed to their clients' money problems.
It also discovered that benefits problems - including administrative errors and sanctions - forced people to seek crisis support.
The report makes a series of recommendations designed to increase people's resilience to "income shocks", prevent gaps in income and improve crisis assistance.
Ms McPhee said: "As our new prime minister takes office, this report makes clear that the social security system is simply not working for the most vulnerable people in our society.
"We make a number of recommendations in our report about how to improve this, and we want to work with both governments to make those changes happen.
"But it is clear that action is needed now."
The DWP said the report failed to take into account the latest statistics on poverty in Scotland.
A spokeswoman said: "Work is the best route out of poverty and since 2010 there are 140,000 more people in work in Scotland.
"We're also continuing to spend around Â£90bn a year on working-age benefits, supporting the most vulnerable in society."
The most vulnerable people in Scotland are falling into destitution because the benefits system is "simply not working", according to a charity.