How to keep stamina during weight loss phase.

At the beginning of this year, I planed to loose 30 lbs before a full marathon on December. Thus I supposed to loose 3 lbs per month. However, since I am running very seriously these days, I lost almost 9 lbs last month.

This is not good at all. If you loose weight too fast, your body will loose its stamina. In fact, this month, I am having trouble in running long distance without walking breaks. My stamina was significantly reduced last month. Indeed, I think I experienced weak depression due to too rapid body weight loss.

Of course, when it comes to running, the lighter body weight the better. However, I cannot loose stamina or endurance to prepare for a marathon. It becomes my current important task to figure out how to reduce my body weight without reducing the stamina. At least, I decide not to loose more than 4 lbs per month from now on.