You heard it right. The American consumer is back in the saddle, and they mean business.

The latest GDP report shows consumer spending accounted for 2.55% of the 3.2% GDP increase in the first quarter. That was the single largest contribution since the fourth quarter of 2006.

Furthermore, the latest consumer spending data shows spending rose 0.6% in March, while personal income grew 0.3%. There's only one way to interpret that: Consumers are increasing spending faster than wages are rising.

Cheer this news, I suppose. It wasn't long ago that the death of the American consumer was the big worry. No one's claiming that anymore. In what seem like headlines straight out of 2005, Apple (Nasdaq: AAPL) has now sold over a million iPads; Herbalife (NYSE: HLF) just reported record revenue; MasterCard (NYSE: MA) reported stellar results after consumer purchase volume jumped 8.3%. This is generally great news coming out of an economy that was completely wrecked a year ago.

Even so, there's good reason to view the spending resurgence with a bit of caution. First, if spending is growing faster than income (as it now is), than spending is coming at the expense of saving. People are spending more by saving less. Sure enough, the personal spending rate has been falling for about a year, from almost 5% last spring to 2.8% this past quarter.

Now, you could rationalize spending gains outpacing income gains if the recent savings rate was abnormally high. But if you look at savings rates going back 60 years, that's hardly the case:

Source: Bureau of Economic Analysis, author's calculations.

Since 1952, the average personal savings rate is 6.25%. There's no explanation for why today's rate is less than half that average, other than consumers being stuck in the bubble mentality of spending themselves to prosperity, safety nets be damned.

Besides, there's actually reason aplenty to think consumers should currently be saving far more than average. Going back to the early 1970s, the average household debt-to-disposable-income ratio is just over 88%. Yet as of the end of last year, households were still drowning in debt levels of 123% of disposable income. The lower the savings rate, the longer it takes to pay down that debt. If consumers were serious about distancing themselves from the excesses of the bubble years, the savings rate would be through the roof as debt was eliminated.

One of the main worries in the financial sector is that the pain was so short-lived -- just a few months, really -- that banks have already forgotten what the fear of failing feels like and have returned to recklessness. Can the same be said of the American consumer? You tell me in the comment section below.

Fool contributor Morgan Housel doesn't own shares in any of the companies mentioned in this article. Apple is a Motley Fool Stock Advisor selection. The Fool has a disclosure policy.