Isekai Heiwa wa Douyara Watashi no Taijuu ga Kagi no Youdesu

In her previous life, Marina was a model. Now that she has reincarnated into another world, she thought to seize the opportunity to enjoy all the foods the world has to offer, however, one day that plan all fell into ruins. If she did not lose weight, she would be disowned from the royal family and the world could possibly be thrown into chaos? The council assigns her a dietitian, but nobody told her she would be living with him. As scary as he looks, he's a little too overprotective. (Source: MU)