There are many reports of torture. Starvation is one of the more harmless things they’d do to you. Here’s a detailed account dating back to the 70s: https://www.un.org/unispal/document/auto-insert-187447/
There’s also a whole Wikipedia article on the history of torture that Palestinians have experienced. This article is easy to find.
There’s also a detailed report on this by Amnesty International. https://www.amnesty.org/en/latest/news/2023/11/israel-opt-horrifying-cases-of-torture-and-degrading-treatment-of-palestinian-detainees-amid-spike-in-arbitrary-arrests/
I find it very cynical to question such a well documented, systemic abuse that has been going on for decades. You can easily find before/after pictures of Palestinian detainees. There’s really no need to make up or exaggerate anything when reality „does the job“ well enough.
Your question is cynical at best, but probably a sad attempt at derailing the discussion. Instead of talking about the well documented systemic torture of Palestinians you want us to discuss the technicality of whether it’s possible or not to lose x KG in Y days. Let’s say it’s only possible to lose x-1KG in Y days. It won’t change anything about the fact that there are ten thousands of Palestinians who have been detained & tortured by an ethno nationalist settler colony that is currently genociding Palestinians.