Troll Thickening (5e Disease)
From D&D Wiki
In some communities where the very specific problem of lack of food and an abundance of wild, dangerous trolls are afoot, the hunting and butchering of these creatures for food has occurred. However, due to the regenerative properties of troll flesh, consuming troll meat initiates an almost perpetual cycle of weight gain and ravenous hunger if not properly cooked, which is a cooking or survival check of DC 11. Some petty folks envious of other's slim figures may also sneakily add ill prepared troll meat into a meal in an effort to ruin their waistline.
Upon consuming the troll meat, nothing happens during the first day other than the stomach making rather loud gurgling noises. By the 3rd day, the gurgling has become more noticeable, which gives disadvantage on stealth checks.
By the first week the changes start to occur, as the gurgling subsides. Due to the troll meat regenerating as it digests, the stomach grows larger and the afflicted increases their overall weight by 20%. This process repeats every single week. In addition, due to the increased stomach capacity the body is tricked into desiring more food. A wisdom saving throw of DC 12 must be passed each day, or the afflicted will consume an additional ration on top of their usual intake as they greedily devour additional amounts of food.
Should the afflicted not be cured by the time their original weight has more than doubled its original weight, the afflicted creature's speed drops by 5 feet. This process repeats every time the creature's weight is doubled, but they also gain 3 HP each time this occurs.
The disease can be cured through the use of lesser restoration, however any physiological changes that occurred during the digestion of the troll meat is considered permanent and is unfortunately only removed through hard work and exercise or the use of spells such as alter self and other transformative magic.