Synopsis

Diets...well, Thomas must have gone through them all. He would lose some weight, then gain it back, plus about as much of the extra weight. As a receptionist at the Orestria adventurer's guild, he doesn't get the chance to exercise much. Not that he can, seeing as his endurance is low.
Then, just as he stopped a new diet, he gets told that an S ranked vampire is offering seminars and couching on weight loss. With no other alternative and not wanting to gain all his two kilograms that he had lost with the last diet, Thomas decides to give it a chance. All Lucius asks for is one litter of blood every three days as payment. And, so, Thomas learns about the magical zone.
And then he puts it to the test. Then, the other diet that he cooks up. After that, the next...
No smut. This is a fat to fit journey with meal plans. I am currently on this diet, so the MC's progress will be the same as my own. You can easily follow the meal plans, if you need to.
The story will be updated at 7 am EEST. It is a book, 70 chapters, and complete.