Hey now, don't forget the Germanic pagan roots - Lent is during a time of year when all the food stores have run out, and there will be limited rations until the ducks migrate in and provide meat and eggs (Easter).

Also, there is value in many of the things you mentioned. Abstinence from unhealthy things that feel good, engagement in healthy activities that feel terrible, and a general ethos of self control are great defenses against akrasia. Also, hygiene is important, and intermittent fasting may have some benefits.