Dr. Judith Palfrey (photo courtesy Obamafoodorama/Eddie Gehman Kohan)

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WASHINGTON--Judith Palfrey, the executive director of First Lady Michelle Obama's signature "Let's Move" project quietly left the White House payroll at the end of December--just months after taking the job in September, the Chicago Sun-Times has learned.

Mrs. Obama marks the second anniversary of "Let's Move" --a drive to end childhood obesity in a generation--this week with an enormous publicity blitz, marked Tuesday night with a taped appearance on the Jimmy Fallon show.

On Thursday, Mrs. Obama starts a three day national tour, stopping in Iowa, Arkansas, Texas and Florida to highlight healthy eating, exercise and helping military families.

Palfrey was the second director of "Let's Move," replacing Robin Schepper; the White House announced her appointment on Sept. 2. A pediatrician, Palfrey is a Harvard graduate with a medical degree from Columbia. She is married with three children.

After her exit in December, Palfrey was given a "fellowship" at the Partnership for a Healthier America, the Washington D.C. based non-profit organization founded in conjunction with "Let's Move."

A White House official said that "Let's Move" is now being led by senior staff:

*Sam Kass, a Senior Policy Advisor for Healthy Food Initiatives, a Chicago native and White House chef.

*Jocelyn Frye, Mrs. Obama's top domestic policy advisor.

*Julie Moreno, a Public Health Advisor for Childhood Obesity, assigned to the Domestic Policy Council from the Surgeon General's Office.

*Kristina Schake, Mrs. Obama's communications chief.

Schake told the Sun-Times, "Judy is now based in Boston to be closer to her family and not commute to Washington every week.

"She is spearheading an important new initiative to mobilize health professionals and engage the research community in support of Let's Move! through a fellowship with the Partnership for a Healthier America. Although she is no longer working out of our office, from her new position she is helping to expand efforts to eliminate childhood obesity in communities across the country."