Conversation so far:
What medical breakthroughs did John Harvey Kellogg make?
Kellogg took keen interest in devising instruments for light therapy, mechanical exercising, proper breathing, and Hydrotherapy.
Did he invent any new equitment?
hot air bath, vibrating chair, oscillomanipulator, window tent for fresh air.
how old was he when he started studying medicine?
CANNOTANSWER.
What other information can you give me about his inventions?
specialized hooks and retractors, a heated operating table, and an aseptic drainage tube used in abdominal surgery.
Did he invent any medicines, or was it only equipment?
less discussed than his food creations.

Question: What food did he make?
Self-contained rewrite: What food did John Harvey Kellogg make?