But I gained weight while doing that routine..

You finally got the decision to change your body. You go to the gym happy that finally you are going to lose weight gaining some muscle in the process. You get a program and you start doing everything religiously in hope that the scale will reflect your hard work. At first you see some results:the magical weight number is lower. Suddenly a day comes when not only you stopped losing weight but you gained weight. You are doing something wrong clearly. But this may not be the truth..

To see what may have happened lets see what I wrote on the post about carbohydrates.

After carbs are ingested they are converted by the body to simple sugar called glucose. Some of this glucose is used as fuel for the body. The rest is either converted to glycogen and stored in the muscles and liver or if the glycogen stores are full converted to fat and stored to the body for later use. Glycogen stores can be mainly depleted by intense exercise.

The key here is glycogen. Glycogen stores depend on the amount of muscle you have. Generally our total body glycogen ,from the liver and muscles, can reach 300-400 grams. Each gram of glycogen can hold 3 grams of water. As you can see this adds up. That's called water weight. So combine this with the above carbohydrate procedure of gaining glycogen and it is easy to figure out that those weight fluctuations are not exercise dependent . There is also the so called body rebound. After a period of intense exercise your body is forced to change in order to be able to handle the extra work. When this period is over the body has a chance to relax and provided the appropriate nutrients it may gain back some of the lost weight.

I hope I was clear that a weight gain even by doing everything right is natural. In the event that you want a steady weight loss you can lower your carb consumption. Also a very helpful thing is to stop obsessing about the the scale and use the mirror to measure your progress.