Is it alright to lose this much weight? How should I do it?

So I feel fat pretty much all the time and I hate eating, I always feel guilty after. I try not to eat more than 700 calories a day. I'm 5'7" and 147lbs and I wanted to be around 110 maybe. Also I have tummy fat I need to get rid of but I don't know how. How should I be losing weight? I tried the keto diet but I'm taking a diuretic and both that and keto get rid of sodium from your body so I'm worried about not getting enough sodium since I already don't eat much. And I heard core training is good for getting rid of tummy fat but I don't know how to do it. Sorry if this was all over the place, I'm bad at asking questions.
Is it alright to lose this much weight? How should I do it?
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