Red meat eaters aren't panicking, yet. Some who subscribe to enormously popular protein-rich diets, such as the Atkins diet, say one case won't cause them to quit the program.
For Birch, whose diet has been red-meat-rich for three years, beef remains the protein of choice.
"If I couldn't eat it, I'd miss it a lot," he said.
So would Don Eaton, 56, of South Philadelphia, who doesn't plan to cut down on the two or three hamburgers he eats a week. Mad cow disease was the furthest thing from his mind as he did a brisk five-mile run through his neighborhood yesterday.
"I'm not worried about it," he said. "I'm not even worried about the flu."
Polls have found that Birch and Eaton are among 9 million to 35 million people who follow a high-protein, low-carb regimen. Atkins Nutritionals Inc. doesn't release information about how many people subscribe to its diet, said Thomas Pendleton, a spokesman for the company. But its popularity seems to have increased in the last year since the New England Journal of Medicine reported that Atkins dieters tend to have success losing weight and dropping triglycerides, which have been linked to heart disease.
Atkins posted a message on its Web site stressing that the risk of humans' contracting mad cow disease was remote and that those concerned about red meat should tap other sources of protein, such as pork, lamb, fish, eggs, soy and cheese.
Beef tends to be a favorite among protein eaters because it's easy to cook and helps build muscle, said D.C. Maxwell, co-owner of Maxercise sports/fitness center in Center City.
Although her clients haven't voiced concerns, Maxwell said she is bracing for questions.
"Everybody has their New Year's resolutions coming up," she noted.
Some people who may have been thinking of going on a protein-based diet could be afraid to try it without beef, she added.
James Hays said he believes that such fear is unfounded. An endocrinologist at Christiana Care Health System in Newark, Del., Hays promotes a high-protein, low-carb diet among diabetic patients as a way to lose weight and feel better.
Believing that the food supply has not been affected by one infected cow, Hays enjoyed a breast of veal for Christmas dinner and a steak last night.
"I am more worried about the administering of antibiotics to animals and creating a super bacteria. And I'm worried about E coli," Hays said. "Hopefully, the publicity on mad cow will get some of these issues on the table."
When news broke last week that a cow from a farm in Washington state that had been slaughtered later tested positive for mad cow disease, it made Leonard Thompson Jr., 32, of Mount Airy, think about his own table, he said while doing bench presses at the Sweat Fitness gym in Queen Village yesterday.
"I thought, that's another reason I should be a vegetarian," he said.
Contact staff writer Christine Schiavo at 215-348-0337 or firstname.lastname@example.org.