We've been keeping our eye on Katie Holmes for a while now -- she was looking a little thin early in the year, when we heard a rumor that she was planning a Scientology detox diet after her Broadway show ended. And then, last month, she was explaining away her weight loss, blaming her seriously skinny frame on her heavy work load.

Well, it's not just work that's slimming her down -- it appears that Katie has been following a rigorous detox diet plan to rid her body of toxins (supposedly as a lead-up to having a second child), and it seems it's just a little too much for her. She and husband Tom Cruise were noticeably absent from last week's Academy Awards, and the "Daily Mail" is reporting that it's because the diet has left Katie simply "too tired" to handle it.

I've always felt strongly that a diet shouldn't leave you unable to do your daily tasks. And yes, I know, the Oscars are a bit more taxing than, say, an evening out with friends, but think about it -- how extreme would a diet have to be to keep you away from the biggest red carpet event of the year? Because I can't imagine how tired I would have to be to miss out on that.

So many celebrities rely on really unhealthy diets to drop weight, and it leads me to wonder: Do they really think these extreme diets are worth it? And do you?