With Gwyneth Paltrow, Shailene Woodley, and Salma Hayek among the many celebrities touting the benefits of nutrient-rich bone broth, it was only a matter of time that the trendy new beverage would be transformed into a full-on diet plan.

In her new bestselling book, Dr. Kellyann's Bone Broth Diet, nutritionist and paleo lifestyle expert Dr. Kellyann Petrucci's promises that followers of her plan will lose up to 15 pounds and four inches - and their wrinkles - in just 21 days thanks a broth made primarily with animal bones and simmered for hours on end.

And after gorging - and inevitably putting on weight - around the holiday months, Femail reporter Erica Tempesta, 31, was ready to put the bone broth diet to the test.

Dr. Kellyann's plan is essentially a mix of paleo and the 5:2 diet. During two nonconsecutive days a week, followers will consume nothing but six cups of bone broth or five cups of bone broth and a 7pm snack. The other give days of the week, they are required to eat balanced meals made up of approved meats, vegetables, fats, and fruits.

For three weeks, grains, corn-based products, refined processed oils, artificial sweeteners, dairy, sugars, processed foods, beans, legumes, white potatoes, and alcohol are forbidden.

Although the consumption of bone broth may seem like a new diet fad, older generations have been using animal bones to make broth as a relatively inexpensive way to create a nutrient-rich meal for years.