A healthy body composition is a direct reflection of what you ingest into your system. Rubbish in, rubbish on the outside. When the numbers on the scale do not reflect your hard work and dedication in the gym, it's easy to blame it on the misinformed belief that muscle weights more than fat, especially if you are resistance training.
Fat and lean muscle weigh the same pound for pound. Muscle has a high density, takes up less space and therefore looks leaner. Fatty tissue, due to its low volume, needs more space to jiggle around.
One pound of muscle burns more calories than one pound of fat!
Since your scale cannot differentiate between lean weight and fat weight, please step away from the scale! I recommend to gage your weight on how your clothes fit. Dump the scale and grab a measuring tape. If your skinny jeans fit, chances are you are transforming your weight ratio from fat mass to lean muscle.
Scale back on stressing about your weight. Stress kills.
Your body is a machine. Treat it with respect and live your BEST life!