U.S. stocks fell on Tuesday as talk of a second government stimulus plan stirred fears that the economy is far from well, raising the specter of an anemic second quarter earnings season.

A member of the Obama administration's economic advisory panel said the United States should plan to possibly provide a second round of stimulus funds to prop up the economy, implying that recovery is still far off.

I think it's insane, the first stimulus package has not even been spent yet, said Andre Weisbrod, president & chief executive of Staar Financial Advisors in Pittsburgh.

They are creating what I would call the government bubble ... When that bursts we are in huge trouble.

The recent rotation into non-cyclical areas of the market continued as investors sought out companies better positioned to weather a weak economy.

Healthcare, a classic defensive sector, was the only S&P 500 sector to avoid losses, rising 0.5 percent <.GSPA>. Consumer staples <.GSPS>, another defensive sector, had the smallest loss at 0.2 percent.

Drug maker Pfizer Inc

rose 0.6 percent to $14.65, while food producer Kellogg Co rose 0.8 percent to $48.19.

But cyclical stocks in the materials, energy, and industrial sectors, which have ridden a recent upswing in raw material prices, lost ground as commodity prices eased as hopes dimmed of a quick recovery. Copper, a barometer of global economic strength, fell nearly 2 percent.

Caterpillar Inc , a maker of heavy machinery for construction and mining companies, shed 3.5 percent to $30.60.

A preview of the second-quarter performance of natural resource companies will come on Wednesday when Alcoa Inc kicks off quarterly earnings season. The aluminum producer, a Dow component, is expected to post a third consecutive quarterly loss.

Doubts about the strength of an economic recovery and subsequent demand for oil have sent crude prices tumbling in the last week. New York crude fell 1.5 percent on Tuesday and is down about 14 percent from the intraday peak hit on June 30. Its slide has pressured energy stocks.

Oil services company Schlumberger Ltd fell 2.8 percent to $50.01 while blue chip Exxon Mobil Corp lost 1.4 percent to $67.15. The S&P energy sector <.GSPE> index lost 1.3 percent.

The Dow Jones industrial average <.DJI> dropped 67.26 points, or 0.81 percent, to 8,257.61. The Standard & Poor's 500 Index <.SPX> fell 6.44 points, or 0.72 percent, to 892.28. The Nasdaq Composite Index <.IXIC> lost 18.73 points, or 1.05 percent, to 1,768.67.

Investor concerns over mounting debt were underscored by a report showing a record number of cash-strapped consumers falling behind on credit card bills in the first quarter.

Shares of credit card company American Express Co shed 1.9 percent at $23.07 and the S&P Consumer Finance index <.GSPCFI> fell 2.7 percent.

A rally in the broad S&P 500 index that had boosted it about 40 percent from 12-year lows hit in early March has wilted in the last month as investors sought stronger evidence that economic conditions were improving.

(Editing by Padraic Cassidy)