One of the country’s most seasoned dieters, Oprah gives high praise to the Quantum Wellness Cleanse, a 21-day program developed by best-selling author Kathy Freston. It eliminates caffeine, sugar, alcohol, gluten, and animal products and includes fruits, vegetables, whole grains, nuts, seeds and soy products. After her 21-day experience, Oprah blogged: "This has been exactly what we intended: enlightening. I will forever be a more cautious and conscious eater."