is it true that if you grow muscles in ur arms and dont work out they become fat!

No, this is not true.

Muscles cannot turn into fat. All they can do is get smaller from not working out.

If you don't work out and don't eat healthy, you will get fat no matter what.

If you want smaller muscles without getting fat, just do a lot of jogging without lifting weights, and eat more vegetables and less meat.

But why? Having muscles makes you burn fat at a faster rate. People with developed muscles burn more calories, even when they aren't doing anything.

They don’t ‘become’ fat... If you do get fat, it’s because your muscle mass (which burns fat) has decreased, and unless you adjust your diet accordingly, you’ll take in more than you can burn (because of less muscle), and then you’ll start getting fat.

Fat does not convert to muscle, nor does muscle convert to fat.

If you want to become skinny again, just stop working out. And you should realize since you’ll have less muscle, you’ll need to consume less food.

No, muscles and fat are completey different organs.

BS they will only be fat if you are still consuming large amounts of muscle building foods.

if your not training you prob wont be eating the same?

Most probably fake.