I had this same experience, but I have not continued to take the medication after a short experiment.
I found I could get a similar outcome (subjective experience) through my food selection
Today I’ve eaten around 2kg of vegetables today (zucchini, capsicum, eggplant, cauliflower, spinach) all of which was under 500 calories,
and I’ve eaten fish.
If I eat a massive amount of vegetables and get ~200g protein, I don’t feel I’m depriving myself and am satiated on under 2000 calories, previously I would typically eat over 3000 on a normal day.
As for people lacking willpower, the genetics of hunger mean all of us experience vastly different levels of hunger. You might be interested to read about the family in Pakistan who could not produce a relevant hormone leptin, and the toddlers driven to fighting by insatiable hunger to steal food from each other, and the dramatic change in their lives after medical intervention with leptin injections