Americans say they feel more optimistic about the economy since President Trump was elected. But they certainly are not acting that way, and that is shaping up to be a challenge for his administration.

Consumers pulled back sharply on spending in early 2017, the Commerce Department said on Friday, reducing the economy’s quarterly growth to its lowest level in three years. In fact, the 0.7 percent annual growth rate for the period is far below the 2.5 percent pace in President Barack Obama’s final three months in office, let alone Mr. Trump’s 4 percent target.

The caution among consumers was particularly notable on big purchases like automobiles. Other indicators were stronger — businesses invested at a healthy pace — but that was not enough to offset the headwinds from feeble retail sales and falling inventories.