Because nobody asked for her advice.

Via Fox News:

Michelle Obama has pushed Americans to eat healthier and to exercise more. Now she says we should “drink up” too. As in plain water. And as in more of it.

The first lady, an exercise fanatic who loves French fries and whose biceps are envied by women everywhere, is getting behind a campaign being launched Thursday to encourage people to drink more plain old-fashioned water. Whether it comes from a faucet, an underground spring, a rambling river or a plastic bottle, the message is: “Drink up.”

She was joining the Partnership for a Healthier America as the nonpartisan, nonprofit group launches the nationwide effort from Watertown, Wis., with backing from a variety of likely and unlikely sources, including the beverage industry, entertainers, media and government. Mrs. Obama is the organization’s honorary chairman.

Every bodily system depends on water, which makes up about 60 percent of a person’s body weight, according to the Mayo Clinic. Water is a calorie-free option for people concerned about weight control, and is largely inexpensive and available practically everywhere.

Yet despite recent trends showing a rise in water consumption and declines in the amount of soda people drink, Larry Soler, the partnership’s president and chief executive, says the “drink up” water campaign is still needed. Health advocates have blamed the corn syrups and other sugars in soda for obesity.

“That’s exactly the type of impact we’re glad to be seeing, and we want to accelerate that because we still have an enormous problem in this country with rates of obesity,” Soler said.