Multiple fighters have already died cutting weight.
Fighter dies during weight cutting, at age 21
While the exact cause of Chinese flyweight Yang Jian Bing’s death is still being determined, his tragic death at just 21 years of age is likely to re-ignite the debate about extreme weight-cutting in MMA.
ONE Championship released an official statement
http://www.mixedmartialarts.com/vault/mma/fighter-dies-during-weight-cutting
Scottish Muay Thai fighter dies in Thailand attempting to cut weight for fight
Muay Thai boxer Jordan Coe, 20, from Scotland has died of a suspected heatstroke while trying to make the weight for a bout in Thailand.
Coe died when he went out in a heavy tracksuit while attempting to shed 3kg to make the 61kg weight limit for a bout on Sunday in Bangkok.
https://www.rt.com/sport/382434-scottish-kickboxer-dies-weight-cut-jordan-/