Before we go any further, let's establish the fact that it’s basically impossible to lose five pounds in a week. Trying to lose this much this quickly is dangerous, from a physical health perspective first and foremost.

Welp, TikTok is here with yet another problematic challenge. And like the 75 Hard Challenge, this one involves a very specific assignment for a very specific amount of time in the hopes of changing the way your body looks. How fun for us!?

If you've ever found yourself both terrified and intrigued by what celebs say they eat in a day, same. Who doesn't wonder whether they'd feel as great as Meghan Markle looks if you also began your days with a green smoothie, avoided dairy and sugar (even from fruit), went vegan, and topped your day off with a small piece of 70 percent cacao dark chocolate.

When a Kardashian shares a weight loss tip, people listen. After all, Kim has been enormously successful losing the 60 pounds she gained during pregnancy; Kourtney lost 35 pounds in the five months following the birth of her youngest child and now uses her app as a platform to blog healthy living tips; and Khloé, who authored the book Strong Looks Better Naked, appears to be maintaining her 40-pound weight loss.

While some of their weight loss strategies are ineffective (and a bit absurd), the Kardashians do have access to the best nutritionists and fitness trainers that money can buy. To figure out which of their weight loss tips are safe and effective for people who may need to lose weight, Cosmopolitan.com asked Philadelphia-based weight-loss specialist Charlie Seltzer, MD, to assess.