Acts 27:33-34:

And while the day was coming on, Paul besought them all to take meat, saying, This day is the fourteenth day that ye have tarried and continued fasting, having taken nothing.
Wherefore I pray you to take some meat; for this is for your health: for there shall not an hair fall from the head of any of you.

Notes on Acts 27:33-34:

Here, as in 1 Timothy 5:23, Paul gives natural advice for someone’s health.  Paul did signs and wonders and healed the sick, but he also used and recommended common sense.  Rather than waiting for people to get sick and then ministering healing, Paul tried to avoid having people get sick in the first place.

See also:

Objection: Paul Told Timothy to Drink Wine Instead of Believing God for Healing