It seems to me that you would be better suited to a juice fast. This provides enough nutrients to move on with daily life but also causes weight loss and detoxification. I understand that you're wanting to keep smoking as an alternative to food cravings but I have to say that this may be the best and easiest time for you to quit. If you were to go on a serious water or juice fast you could rid yourself of your nicotine addiction at the same time. With all due respect I don't think your plan sounds like a very good weight loss option. It actually would probably degrade your health. More like a crash diet. If you don't want to do a water or juice fast then just write up an eating plan with plant based foods. You'll shed weight consistently and increase your health. Just remember as in any diet, it's not so much what you do for the duration of it but how you continue afterwards. That goes double for any kind of fast.