A new gym-goer finds an exercise routine, sticks with it, and the pounds start coming off at a regular clip—until something changes. Not the person; they’re still exercising as hard as ever, sometimes harder, but the weight loss has stopped. What happened?
Weight loss is 80% diet 20% exercise. You could lift and run all you want, but if your diet is poor and you are eating at a calorie surplus everyday – you will not lose weight. At the same time if you eat at a calorie deficit but do zero weight training you will lose weight but also look horrible because you will have little to no muscle definition. The key is to constantly be eating at a deficit while weight training.