I lose over 25 lbs. every Lent ever since I started doing the traditional Lenten fast. Mind you, I am a sixty-year-old Catholic priest who has a decent-sized paunch, which very much appreciates this yearly downsizing. Of course the weight comes back by the end of Christmas each year!
The traditional Catholic Lenten fast, what it was for many centuries before the Second Vatican Council, was basically no breakfast. "Breakfast" means to "break" the Christian "fast," in most of the major European languages, a living testimony to that immemorial Catholic penance of Lent. That rule meant no food or drink from midnight to midday on a day of fast, except water and necessary medications.
In 1962, throughout the world, the fast was required for all Catholics within the ages of 18-59 on all the days of Lent, except Sundays and 1st Class Feasts. Abstinence for meat bound all from the age of 7, and it included total abstinence from meat on Ash Wednesday and all the Fridays of Lent (some places included the Wednesdays and the Saturdays of Lent for total abstinence, which I also do) and partial abstinence on all the other penitential days of Lent (which meant meat only at the major meal of the day).
What is more, I do the added penance of no meal at all on Ash Wednesday and all the Fridays of Lent, just taking water on those days, and a little bread with some simple condiment (e.g. butter) in the evening, so as to deceive the stomach to feel that it has eaten! It works!
There is no feast in this vale of tears without a fast. That is the long-standing Catholic tradition. Do it!
Happy Lent!