TG20, respectfully, I think we're talking past each other.
I TOTALLY AGREE with what you're saying; my wife runs almost daily. She and her best friend are committed to improving their health. They are in no wise "obsessed" or otherwise unChristian in their efforts. They simply want to be healthier than they have been in the past, and regular exercise, diet and mutual encouragement are ESSENTIAL to that process.
ALSO essential to the process is the discipline of daily prayer, humility before God in imitation of Our Lord Jesus Christ and Our Lady and a profound mistrust of our flesh, its desires and its potential to entangle us in temporal passions and appetites.
We're saying the same thing; we're just emphasizing the two different aspects of the topic.
How is there a way to combat the sins of the flesh?
It starts by asking the question: "What GOAL does going to this place (doing this activity/saying these words/thinking these thoughts, etc) have?
If, for instance, one were given overmuch to drink, it would be unwise to attend a party at a bar, because the INTENT of the owners of the bar is to sell alcoholic beverages. Their intent may not be to get you drunk; it may not be to help you sin, but their intent IS to offer freely those things which you KNOW you cannot manage responsibly.
Likewise, take the common (in the US, anyway) task of purchasing automobile insurance (I don't know if such a thing pertains everywhere in the world). When I was shopping for insurance, I found a VERY good rate, well below even some of the most well-known providers' rates, with a company that is newer on the national scene, yet VERY recognizable because of a series of trendy commercials with a familiar spokeswoman.
I would have jumped on that rate immediately and saved myself hundreds of dollars a year, but I first investigated what that corporation DOES with its profits. Some of the things they support include "right to choose" efforts, "marriage equality" efforts and programs which foster an overemphasis on "animal rights" over against those of humans.
I obviously could not give my money to a company that publicly aligns with so many non-Catholic agendas.
That's the long answer.
The short answer is: Pray to Our Lord daily. Ask the intercession of Our Lady and the saints daily. Call upon St. Michael, et al, to defend your soul in battle.
In all of that, simply ask yourself whether St. Paul's First Epistle to the Corinthians is advice you're heeding daily:
"Whether you eat, or drink, or whatever you do, do all for the glory of God."
Don't think about spiritual warfare so much in terms of the "NOs" you have to tell yourself. That can lead to a Jansenist, up-by-the-bootstraps mentality that is offensive to God.
Rather, think about spiritual warfare as a PRIVILEGE Our Lord has won for your soul. Act like the action heroes in movies; they go into a closet or cabinet and arm themselves with every conceivable gun, bomb, knife, sword, whip, tank, helicopter and who-knows-what before they stride off into battle.
You have weapons at your disposal that are mightier than ANY earthly weapon, because earthly weapons can only kill the body. OUR weapons, says St. Paul, are mighty to the pulling down of SPIRITUAL strongholds in our lives and in the lives of others.
Our Lord's Cross is they KEY to an inexhaustible armory of meritorious weapons that, used devoutly and free from mortal sin, are the most powerful tools of exercise of the soul we could ever have.
Want to combat the sins of the flesh? Remember the acronym PRF:
PRAY without ceasing.
RESIST the Devil, and he will flee from you.
FLEE from temptation (occasions of sin).
St. Michael, Archangel, defend us in battle.
St. Paul, holy Apostle, pray for us.
Our Lady of Mt. Carmel, pray for us.
Most Sacred Heart of Jesus, have mercy on us.