I don't want to be pedantic, but this is a question that probably not even most professional economists will be able to give you a simple (or even accurate) ans

I don't want to be pedantic, but this is a question that probably not even most professional economists will be able to give you a simple (or even accurate) answer for. This is not because mainstream economics is intellectually bankrupt or anything, but it's because economics is extraordinarily complex. A million variables affect the economy of any nation. Similarly, inflation and deflation do not exist in a vacuum; the currency is not the only variable influencing inflation; thousands of other variables can affect inflation; ditto for GDP. Inflation does not directly lead to or cause higher GDP, unlike what you seem to imply. But it's generally agreed that moderate inflation is necessary and unavoidable for growth, and is preferable to the consequence of tightening monetary policy, which is lower GDP growth. The textbook example for one (out of hundreds) of the possible reasons for stagflation is a rise in commodity prices. For example, the US experienced a long period of stagflation in the 1970s because oil prices skyrocketed - not because of inflation, but because several Middle Eastern nations stopped/curtailed oil shipments. This is called a "supply shock" in economics, and it causes inflation by increasing prices, while decreasing GDP by making it more expensive to buy the resources (e.g. oil) necessary for production. Another "textbook" reason (again, I have no idea whether these actually apply to Brazil) would be a loose monetary policy (high inflation), coupled by heavy government regulation (low GDP).