Washington investors who swallow everything they're fed about the low-carbohydrate-diet fad are setting themselves up for a bad case of fiscal indigestion.

Every company with a low-carb product on its menu is being touted as an Atkins investment. The trendy diet has also become the universal excuse for companies in the grocery or food business that have had a bad quarter.

Among the hardest to swallow are the claims of Krispy Kreme Doughnuts Inc. Skeptics have long predicted that Wall Street would one day have its fill of Krispy Kreme's pricey stock. The choke point seemingly came this month when Krispy Kreme, pleading Atkins, lowered its forecast for the year. The stock's price has plunged since, reaching a three-year low of $19.31 last week, down from almost $50 last summer.

"It's a little bit like the stock market and the Internet stocks back four or five years ago," said William B. Frels of Mairs & Power Inc., a St. Paul, Minn., investment firm. Its holdings include meatpacker Hormel Foods Corp., which says it is benefiting from Atkins, and cereal maker General Mills Inc., which says it is being hurt.

So there's a lot of baloney out there. But there's also some real meat on some of the low-carb investment tips.

Take Virginia's Smithfield Foods Inc., the nation's biggest pork producer, whose stock hit a 52-week high last week thanks to the eat-all-the-meat-you-want prescription of the Atkins advocates. Smithfield and other packing companies are living high on the hog.

"Demand is just unbelievable," Smithfield spokesman Jerry Hostetter said, noting that U.S. pork production hit record levels last year and is up 7 percent this year. The stock price has not fallen, as it usually does when production is strong.

"Low-carb is here to stay," chief executive Joel W. Johnson of Minnesota's Hormel Foods Corp. said in a conference call with investors last week as Hormel announced a 59 percent increase in profit in its fiscal second quarter, which ended April 24.

Thanks to Atkins, South Beach and other diets that stress eating lots of protein, consumption of beef, pork, chicken and turkey continues to grow even though prices are up sharply.

Sirloin costs $2 a pound more than it did last year, the National Cattlemen's Beef Association reported last week. Hamburger is up 29 cents a pound, and the price of Spam will go up in June, Johnson said.

Defying the usually predictable supply, demand and price patterns of the meat industry, high prices haven't hurt sales.

"Domestic consumption of all meat types have increased due to the Atkins diet trend," Wachovia Securities analysts Jonathan P. Feeney and Linda Huang said recently. (Wachovia and affiliates own Smithfield shares and do investment banking for the company.) "Consumers have been turning away from carbs and towards protein, causing a healthy environment for all protein players."

For investors who want to bet on protein, they said, "there is no better place to be than the pig pen," giving Smithfield stock their highest rating, "outperform."

Smithfield Foods stock is up 39 percent over the past 12 months, closing Friday at $27.51 after hitting a high for the year of $28.11 last week. With his company's stock selling at its highest price ever, Smithfield Chairman Joseph W. Luter III cashed in 1 million shares a few weeks ago, taking home $26 million in Atkins-assisted profits. (Luter is nearing retirement age and is diversifying his holdings for estate planning purposes, a spokesman said. He still owns 4 million shares of Smithfield.)

Even after the recent run-up, Smithfield stock could go higher because it is lagging behind shares of some other meat producers, the Wachovia analysts said. For example, Tyson Foods Inc. stock jumped from $8.75 a share a year ago to $19 now. Besides being the nation's biggest chicken producer, Tyson also owns IBP, the No. 1 beef packer.

It's unusual for the beef, pork and chicken industries to prosper simultaneously. Each meat tends to follow its own cycle. Consumers tend to trade one meat for another -- eating more chicken when pork prices are high, bringing home the bacon when pork is cheap. This time prices and consumption of all three are high.

Smithfield is not only the nation's biggest packer of pork and pork products, it's the biggest hog farmer, raising more than 13 million pigs last year.

The two sides of Smithfield's business are intended to be countercyclical. When hog prices are cheap, Smithfield the packer enjoys low prices for raw material and makes more money on its bacon, ham and other processed products. When hog prices are high, packing margins are usually pinched, but the hog-raising half of the business becomes more profitable. But now, even with hog prices high, demand is so strong that both sides of the business are prospering at the same time.

There's no question that low-carb diets are helping, Hostetter said, "but it's impossible to say how much is related to it."

While Smithfield is getting fat on the low-carb Atkins diet, the company spent years associating itself with the rival low-fat diet.

Careful crossbreeding has produced slim hogs and made pork "the other white meat." Smithfield touts its "lean generation" pork as the lowest-fat pork on the market.

Smithfield's newest product is aimed at yet another diet trend: the precise portion control dictated by many weight-loss regimens. Since those diets typically call for six-ounce servings of meat, pork chops exactly that size were recently introduced by Farmland Industries Inc., a big Midwestern pork packer that Smithfield acquired last year.

No such moderation is required by Atkins apostles, who tell dieters they can eat all the meat they want as long as they lay off the carbohydrates.

Atkins is even boosting sales of fried pork rinds, which hardly anyone would classify as health food. Atkins suggests fried pork rinds as a snack, since they don't have the carbohydrates of potato chips, pretzels or tortilla chips.

Fried pork rinds are one of the few pork products that Smithfield doesn't make.

"It's a very specialized business," Hostetter said.

But Smithfield does supply rind fryers with raw material, skin that comes from pig bellies. Thanks to Atkins, demand for the raw rinds is so great that Smithfield is selling them for twice as much money as it did last year.