Celebrity Fit or Fad: Heidi Klum

Heidi Klum, wife of singer Seal, didn't need to watch her weight for her latest role in the animated film 'Hoodwinked Too', however if she did, she wouldn't have much to do. Heidi, 37, is a mother of four, who has maintained her supermodel body for almost 20 years since her professional modeling career began in 1992. Her trainer David Kirsch's program may be the reason why she's bounced back to her pre-pregnancy weight after giving birth multiple times. It was Kirsch, owner of Manhattan's Madison Square Club, who helped Klum walk the Victoria's Secret runway only eight weeks after giving birth in 2009. Of Kirsch, Heidi says, "He really kicks my butt hard."

His book, The Ultimate New York Diet, is one that boasts a diet and workout plan that offers phases that start off extreme and progresses to less stringent nutritional guidelines. For the first two weeks of the program, Phase 1 calls for eating five times a day and avoiding alcohol, bread, starchy carbs, dairy, coffee, added sugars, fruit, and most fats. Phase 2 allows for adding one extra carbohydrate to your diet daily, as well as whole grains and some healthy fats, and Phase 3 is classified as the 'lifelong' phase and allows for slowly introducing more variety into your diet, yet still sticks to high protein, low carbohydrates most of the week. Meals that are recommended in every phase of the program includes high-protein foods like egg whites, turkey bacon, and organic chicken and salad and low-carb vegetables. In the way of exercise, the Ultimate plan calls for exercise daily for up to 90 minutes. Weights and cardio are factored into the workout regimen.

Verdict: Fad

While celebs like Naomi Campbell, James King, and Liv Tyler have all been reported to use Kirsch as a trainer, the Ultimate New York Diet may not be healthy in the long run according to Andrea Giancoli, MPH, RD, former spokesperson for the American Dietetic Association. She says, "The diet lacks adequate calcium, fiber, (recommending a high-fiber meal replacement powder), folate and likely other vital micronutrients. Daily recommended menus average a dangerously low 900 calories, making complete nutrition from food nearly impossible." The National Institutes of Health's article on obesity reveals that diets that require less than 1,100 calories a day (which Phase 1 and 2 seems to call for) are "extreme" and says they are "not thought to be safe or to work very well." However there is a positive side, Andrea adds, "In the author's favor, he does promote lean protein sources, vegetables, nuts (with a preference for almonds) and legumes; and restricts foods high in saturated and trans fats, which is solid advice." However she questions the longevity of it saying, "The real question is; How long can you keep this up? And can your body sustain itself long-term living on so little?"