Brief Answer:
Natural proteins like fish and egg white.

Detailed Answer:
Hello Mr. XXXXXXX

Thank you for posting your query.

Lifting weights on a regular basis stimulates the muscles to grow which requires proteins along with adequate energy in the form of carbohydrates.

Best sources of complete proteins include fishes, eggs, pulses and green leafy veggies.

Many of the marketed protein supplements have been known to contain heavy metals such as arsenic, mercury and cadmium and in your other query you had asked if protein supplements can cause nose bleeds and the answer is yes if they contain any amount of arsenic.

These metals should not be present in any amount at all in the protein supplements and if they do contain these metals then you are exposing yourself to a great risk of developing chronic and debilitating neurological disorders along with chronic kidney failure. Arsenic and mercury are both very dangerous metals and should never be consumed.

I would urge you to get yourself tested for presence of arsenic in your system, if present, you will need to undergo treatment to remove the metal from the body as this metal is not easily excreted normally.

Please eat only those foods that are natural, like fish and eggs, fishes contain more than adequate amounts of proteins. Adding green leafy vegetables will also ensure adequate dietary fiber and plenty of essential vitamins.

I sincerely hope this will help you.

Wishing you good health.

Kind regards.

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