Day 21 on phentermine and low carb diet. I have actually got use to knowing what I can and can't eat or drink. This low carb diet isn't all that bad after all. At first I was thinking I am not going to be able to eat anything and always be hungry, but that is so not true. You can look online or get a recipe book and look up low carb meals. One of my readers brought to my attention that the feeling the phentermine ( that energy rush feeling) does kinda go away after the first week. So I decided to skip a day and work out and eat right with out taken the phentermine and just took it the next day. That's one way you can feel that energy again. Remember to continue to drink your water. With this being day 21 I feel great and I feel like I have come along way and glad it's paying off.