Fat loss does not always result in weight loss. Let me repeat that again, fat loss does not always result in weight loss. Not losing weight while you are losing body fat is not necessarily bad. Here is why...
Stop driving yourself nuts by the number on the scale, and start taking notice of the other benefits of "fat loss." There is a difference between losing fat and losing weight. Now I am not saying that if you lose fat, you will not lose weight. There are several factors that can result in fat loss and in weight loss. For instance, one effective step to fat loss is building lean muscle. When you replace fat with lean muscle, your size will shrink, but your weight will stay the same and you may even gain a little. That is why you may have been working really hard with a resistance training program, lose dress/pant sizes, only to find yourself gaining weight. You are building muscle your body did not once have and losing fat in the process. Muscle weighs close to twice as much as fat, but carries about half the size. So a pound of muscle is close to half the size of a pound of fat. Your arms, legs, butt, etc that were covered in fat are now being replaced with lean muscle and will lose half the size, but still carry that same weight. The lean muscle growth is burning fat, but balancing out the weight. As for females, do not worry about getting bulky when doing a strength training routine. You do not have enough testosterone to get bulky like men.
Resistance training is important to losing fat and weight loss. You need lean muscle to have a healthy functioning body, plus lean muscle is a fat burning machine. When lean muscle is exercised, it will burn calories hours up days after you trained them. You may lose a ton a weight by doing cardio and through your diet, but implement resistance training into your routine, it's good for you! Your "weight" loss may be slower, but you will lose fat faster and your sizes will melt off.
Gaining weight when you first start a resistance training program is normal, but remember, you are still burning fat. As soon as your body builds the right amount of lean muscle you will continue to burn fat, and when your body builds the lean muscle it needs the weight will start to come off.
Do not be intimidated by the slight weight gain in the beginning from resistance training. Start judging a lot of your fat loss results from your pant and dress sizes. Weighing yourself daily and weekly can drive you nuts, especially if you are not losing the weight, but you are losing the fat. Take notice of how you feel and look, versus the weight. Remember, the weight will come off, it just takes time for you body to adjust from the new muscle you are building.