Actually, I think yes. Because my friend had a muscle in her arms WITHOUT exercise. Amazing eh? Our conclusion: the reason she had a muscle in her arms is by combing her hair. Weird? Yes. But it's true! She combs her hair for a few minutes. Combing your hair uses your arms right? Then probably after a few months or weeks, you'll have a muscle in your arms. Haha. Why won't you try it? It may work. :)
By getting exercise.
It could be the increase of muscle.
Answer: Your frame size will become larger so you will gain weight, but not from muscle mass. You can gain muscle mass from exercise.
Exercise in a way where you don't lose weight but gain muscle weight.
Yes you most definitely will gain weight if you eat protein and not exercise. If you're working out to gain muscle, this tears your muscle fibers and the protein is used to repair the fibers. If you don't work out, the protein is going nowhere except your hips.
The best way to exercise without building "short muscles" is swimming, running and other cardiovascular exercises. The best possible exercise for your joints, while toning your body is swimming.
high protein diet with regular exercise,
Eating tuna helps to gain muscle because tuna is protein and protein builds muscle. However, to build muscle you need to exercise as well.
No that is impossible. You cannot gain muscle mass without ever gaining weight.
lift weights and gain muscle
Muscle does not turn to fat.
It only provides increased amounts of the nutrients necessary for muscle growth. If you do not exercise, no. You will only get fatter.