Is not eating anything after a workout bad for you? some days i would lift weights before i slept, but ate in morning. can this cause muscle atrophy?

Not "bad": It is ideal if you eat a little something to help rebuild the muscles while you sleep. Be sure you are hydrated. Cant say that it causes muscle atrophy...It is simpy not the best plan for your body's recovery. It will use reserves when it should use fresh fuel.

Not necessarily: I actually prefer eating light before a work-out. Muscle atrophy is usually from lack of use or insufficient protein. Some drugs, like statins, can also cause muscle atrophy. At 17, your muscles should not atrophy unless you are not eating enough. Get protein from nuts, beans, quinoa, and wild salmon. Avoid whey or cassein. If problem persists, see a doctor.

NO: Regular exercise makes the body burn fat rather than sugar and therefore athletes do not necessarily feel hungry after exercise. There is no danger of muscle atrophy under these circumstances.

Eat!: Independently of your activities you need to eat a balanced diet. The most important meal of the day is breakfast. Never skip it. Not eating some meals very unlikely will cause atrophy of muscles, specially if you are working out. The important thing is to have nutritional intake. A nutritionist is the ideal professional to consult.

It is bad for you: If you exercise by weight lifting, it is best to replenish the protein and carbohydrates you've needed in order to lift weights within an hour after stopping exercise. You're breaking down muscle by lifting, and consuming protein with some carbs to help absorb the protein in that first hour will help ensure adequate muscle repair and growth. Otherwise, you're just breaking down muscle for energy.