1 Timothy 4:7-8:
But refuse profane and old wives' fables, and exercise thyself rather unto godliness.
For bodily exercise profiteth little: but godliness is profitable unto all things, having promise of the life that now is, and of that which is to come.
See also:
Bodily Exercise Profiteth Little
I’m Sick Because I’m Fat! Can I Claim Healing?
Is It OK for a Christian to Practice Yoga?
Objection: Paul Told Timothy to Drink Wine Instead of Believing God for Healing