How can I bulk up with a ridiculously swift metabolism?

I'm 16 and I'm looking to fill out a bit bit. I've been growing taller and taller, which is mundane, but my weight is staying pretty much steady at 140. I'm approaching 6 foot and I want to start to fill out and rather get some muscle definition. Suggestions, please?

Answers:

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Try drinking a high protien diet. Lots of lean meat, fish, nuts, etc. A lot of times ingestion protien helps to build muscle on your body. Also, hold you tried lifting weights. That should also build muscle.

Is it harmful if my wife squeezes my testicles during sex?

Protein, and exercise

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Eat more to counter your body met. High protein, dignified carbs, limit stout. Adequate fruits and veggies. Egg whites, try eating 6-8 a daylight. (Do not include the yolk - high cholesterol, unless you want to die childish.) Yeah, I know, waste of egg yolk, but ... d:

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i wouldnt worry. im 14, 5'8" and with the sole purpose 115lbs or so. Im very skinny - no excess weight...just muscle and bone and skin. Be content.