The Torah does say to lead a balanced life. It also warns us not to put ourself in a Sakana...danger.
However...some of us have certain Teyvahs...desires...that are out of control...
If I were you but I'm not...and this may not work for your personality?) I would sit my dad down and say "I want to speak with you. I am asking you to please listen to what I have to say and not say anything until I have finished. Then you can say your piece and I will also not interrupt. Dad, I love you. I am worried about you and your health. I am scared of losing my father to his Teyvah for sweets. It hurts me every time I watch you use up another day of life from Hashem with your eating. It's a Sakana! And it is aginst the Torah. It also hurts me that you do not seem interested in the food I worked so hard to make you." I would say whatever you need to get out in a respectful way. I might also let him know that it is hard for you to say these things as you have a deep respect for you. But that you feel in order to be a good daughter you need to tell him your concerns.
I hae free long distance Dalia. If you want me to call you I'd be honored. You've helped me change my life...if I can ever do anything for you I'm there in a heartbeat!
I have you in my thoughts and Tefilos (prayers)....