Set-point theory suggests that your body defends a preferred weight range
(2019) Erastin, a ferroptosis-inducing agent, sensitized cancer cells to X-ray irradiation via glutathione starvation in vitro and in vivo , PLoS One , 14 , 0225931, doi: Louandre, C., Marcq, I., Bouhlal, H., Lachaier, E., Godin, C., Saidak, Z., Francois, C., Chatelain, D., Debuysscher, V., Barbare, J.-C., Chauffert, B., and Galmiche, A
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Effects of variation in the dietary supply of cysteine and methionine on liver concentration of glutathione and active sulfate (PAPS) and serum levels of sulfate, cystine, methionine and taurine: relation to the metabolism of acetaminophen
There's no established "ideal" percentage yet but 1-2% is the evidence-backed range