Vegetable oil in Iran cost 383 per cent more last month than it did a year earlier. The currency is collapsing. Six months into the war, the economic pressure on Iranian households has become the dominant fact of daily life there, and it is receiving a fraction of the coverage given to missile exchanges.

Why cooking oil is the number to watch

Of all the prices that could be quoted, vegetable oil is unusually informative, and not because it is dramatic.

Iran imports most of its vegetable oil. Imported staples are priced against foreign currency, so their local price tracks the exchange rate almost directly — which makes them the fastest indicator of a currency losing value. Domestic goods lag; imports move immediately.

Cooking oil is also not optional. It appears in nearly every meal, cannot be substituted away from easily, and takes up a much larger share of a poor household’s spending than a wealthy one’s. A 383 per cent rise is therefore not evenly distributed pain. It is concentrated at the bottom.

How the mechanism works

The chain runs from oil exports to the dinner table, and each link is visible.

Iran earns most of its foreign currency selling crude. Constrict those exports — through the blockade regime, the tanker interdictions and the disruption around Hormuz — and the supply of dollars entering the country falls. Fewer dollars against unchanged demand means the rial buys less. Importers pay more for the same shipment. Consumers pay more at the shop.

There is usually a second effect layered on top. When people expect a currency to keep falling, holding it becomes irrational, so they convert savings into goods or hard currency — which pushes the exchange rate down further. Expectation becomes cause. This is the standard dynamic of a currency crisis, and it is the reason such episodes accelerate rather than easing gradually.

The argument about whether this is the point

Economic pressure on Iran is a stated instrument of policy, and there is a genuine dispute about what it achieves.

The case for it is that a state’s capacity to fund a military and a nuclear programme runs through its export revenue, that constricting that revenue constrains what it can do, and that a government facing domestic economic distress has stronger incentives to negotiate. Iran’s president has said Tehran will reciprocate if the United States honours its interim deal commitments — which supporters read as pressure producing movement.

The case against, made by sanctions researchers over several decades, is that states protect military spending first and let household consumption absorb the shortfall, so the population bears the cost while the targeted capability is affected last. The literature on this is not unanimous, but the general finding is that broad economic pressure reliably produces hardship and unreliably produces policy change.

A third argument, harder to test, holds that economic distress can strengthen rather than weaken a government by giving it an external cause to blame. Both sides of this debate have cited Iran as evidence for decades.

What the figure does not tell you

One price is not an inflation rate. A 383 per cent rise in one imported staple sits at the extreme end of a distribution that includes goods with far smaller increases, and quoting it alone overstates the general picture.

Iranian official statistics are also of limited use here. Governments in currency crises have both the incentive and the means to publish favourable figures, multiple exchange rates typically operate at once, and subsidised and market prices coexist for the same goods. What people actually pay and what the statistics office reports can diverge substantially.

The reliable signal is direction and rate of change rather than any single number, and both point the same way.

Related: The Target Was Not a Ship. It Was the Lane Itself.

Sources

Price and currency reporting via Democracy Now, carried by Havana Times; Iranian president’s remarks on interim deal commitments via The Cipher Brief.