Who says you shouldn’t eat less than 1800 kcals? Under normal circumstances, the minimum is 1200 for women, 1500 for men, and height and weight have no bearing – these are what the body requires to avoid starvation. This diet is, however, for 7 days only, it is not intended as a long-term weight-loss strategy, so 6 days at less than 1500 won’t do you any harm. You don’t say how tall you are, or what you do for a living, which would also have a bearing on your long-term weight-loss plans. Good luck with it, anyway – it’s not easy

Larson-Meyer, D. E., Willis, K. S., Willis, L. M., Austin, K. J., Hart, A. M., Breton, A. B., & Alexander, B. M. (2013, June 8). Effect of honey versus sucrose on appetite, appetite-regulating hormones, and postmeal thermogenesis [Abstract]. Journal of the American College of Nutrition, 29(5), 482–493. Retrieved from http://www.tandfonline.com/doi/abs/10.1080/07315724.2010.10719885