This survey seems pretty ambiguous, but assuming the following:
- Banks grant credit only to those who are in a position to afford food
- Banks will not grant credit to those who cannot afford food
- Poor people may find seasonal or part-time work, or may grow their own crops. This means that most of the time they will be able to feed themselves.
- Occasionally, they will need extra money, during tough times. In such cases, they will tend to borrow from friends and relatives (as mentioned earlier, banks are unlikely to grant loans)
- When they have money again, they pay their debt.
- In any country, poor people make up the majority.
It seems logical therefore that most people will borrow money for food, and this is not unsustainable.