The F-Factor Diet is based on the idea that taking in more fiber will slim you down and keep you lean.; The F-Factor asks you to eat even more than the recommended amount of fiber for women—35 ...

Still, Zuckerbrot continues to promote her diet plan and F-Factor’s products, and frames the controversy as a smear campaign started by jealous competitors out for financial gain.

Fibre has also been a recurring theme, from the F-plan diet of the 1980s to today’s focus on gut health. Conrad Astley, of the Good Food Institute, ...

The diet encourages followers to start with a 1,200-calorie-per-day, high-fiber plan. Ms. Zuckerbrot is the owner of a nutrition consulting business in New York that charges some clients $25,000 ...