In general the Jewish religion does not believe in abstinence and avoiding the good that Hashem has provided for us in this marvelous world He created (Aside for the halachicly prescribed fast days). Our job is to employ it in a meaningful way to serve our Creator and not just satisfying our bellies.
Eating performed to strengthen the body to have energy to do mitzvos and learn torah, in itself is considered a great mitzva. In years gone by fasting was a means of making up for sins. However in our weakened state that is not done much today. Especially given that we have not come close to fulfilling our obligation of full repentance and regret.
The great Baalei Mussar tell us that not eating a food in front of you, that is calling your name, is considered like fasting. So if you want to fast eat a solid meal and just hold off on that last bite.
If you have already shed rivers of tears over your sins then maybe you are ready to ask your Rabbi about taking on fast days special fast days. If not then the best way to repent is to make up your mind to to really regret your past and truly abstain from them in future. Eat ,well stay healthy, and serve Hashem!