Re: Weight loss V. Fat loss v. Muscle loss
Exercise increases your body's protein requirements. If you don't take in enough protein or if you don't have it often enough, then yes you will lose muscle. Unlike fat, the body cannot store protein so you need to give your body a continuous supply. If your body doesn't get the protein often enough, it will break down muscle to get it. I generally try to eat protein every 3 waking hours and I eat the same amount of protein per meal.
As for whether the Weight Watchers plan gives you sufficient protein, only you can answer that by monitoring your lean body mass each week. Usually if a person is losing muscle, it's the result of not taking in enough calories, not taking in enough protein, or not eating it often enough. Personally, I would stop using the weight watchers plan. Any plan that doesn't take into account a person's body fat percentage and lean body mass is a bad plan. What you need to do is come up with a plan that suits you based on your goals, your body's requirements, and how it responds to exercise. Just base it on the principles that apply to everyone such as eating smaller more frequent meals, drinking lots of water, eating more protein, fiber, and complex carbs, less simple carbs and saturated fat, performing cardio and weight training, etc.