if she's only borrowing the amount she needs to pay off the other loan, it's not 'more' debt.
She would have to pay back interest on the new loan, in addition to the interest that has accrued on the old loan. So it is more debt in the sense that she would owe more money in interest payments. (Assuming that she couldn't get a lower interest rate on the second loan.)
And considering the reason she would be taking the loan, if any bank would loan her money, they would probably charge her quite a high interest rate, as she is already a bad credit risk. If she could get the bank to lend her money at a lower interest rate than she is paying now, it would be worth it.
She could shop around and see if she could get a loan that would be worth it.
P.S. This is the latest I could find from the FSA re debt consolidation:
A range of products are being marketed at consumers with debt repayment
problems, including debt consolidation loans and debt management plans.
Sales of these products are not covered by our conduct of business rules,
but can raise concerns from a public awareness perspective. Debt
consolidation loans and management plans typically reduce the borrower’s
monthly debt service payments, but spread the debt over a longer period of
time, ultimately resulting in higher borrowing costs. Secured debt
consolidation loans have been popular, driven partly by the amount of
equity accumulated in property, but also because if the borrowing is secured,
this can secure a more attractive rate of interest. But the borrower also runs
the risk of having their home repossessed in the event of default. Interest
rates for these types of products are not as competitive as a conventional
re-mortgage provided by a high street lender and broker fees can be high.
Source:
http://www.fsa.gov.uk/pubs/plan/financial_risk_outlook_2004.pdf