Yes, I have been for last 9 weeks and lost 42lb in that time. Most of it in first two weeks. I started out with a lot to lose though and still need to lose loads more. I have Pcos, insulin resistance and various other health issues that mean that it is medically advisable for me to eat this way. I have found that it greatly reduces hunger and cravings though which is the secret for me sticking to calorie deficit.