I understand your concern
Welcome to HCM
Your partner needs a medical check up and not only diet change.
There are multiple areas where he should change his life style itself.Smoking
is bad. Living in chocolate, sweets and dnergy drinks never gives him energy, but gives him addiction to caffeine and certain other addiction inducing chemicals.
Actually he is an addict to these things now.
Chocolate and sweets are also know to decrease hunger.
Everything combined, he should be very stressed and anxious now.
Therefore he needs advice from GP, psychiatrist
and family for a life style change.