How much fluid is actually needed, and how you would know

The question in the title: How much fluid is actually needed, and how you would know I will give what I have already checked below so nobody repeats it.

Maintenance rather than loss, which is the part of this that almost nobody writes about.

I have been at roughly the same weight for 7 months. The interesting questions are all different from the ones I had at the start, and the documentation here is much thinner on this phase.

I would like to compare notes with people who are further along, and I would like to know what the published evidence says about this phase specifically rather than by extrapolation.

This follows the opening post rather than contradicting it.

Lab testing: if symptoms are severe or persistent, checking electrolytes and minerals (sodium, potassium, magnesium, calcium) and interpreting them in context of losses during weight loss is reasonable.

The very ordinary causes of week-two malaise: inadequate hydration, low sodium intake, too-rapid calorie deficit, and inadequate sleep are more common causes of fatigue and malaise than compound toxicity.

Magnesium: deficiency during weight loss is common and symptoms (fatigue, muscle cramps) are nonspecific. Supplementation is inexpensive and low-risk if needed.

Coming back to post #3, because the follow-up matters more than the original answer.

Practical note that does not fit anywhere else. Whatever you conclude from this topic, write down what you did and when. The single most useful thing in your own records is not any individual result; it is that they are dated and consecutive.

Orthostatic symptoms: dizziness on standing after lying down can indicate dehydration or electrolyte depletion. Increasing fluids, salt, and potassium usually resolves it.

Exercise and electrolyte losses: sweating during exercise increases sodium and potassium losses. Electrolyte replacement during or after intense exercise helps maintain balance.

Fluid intake: baseline needs increase with gastrointestinal effects and exercise. Thirst is not a reliable guide during appetite suppression. Drinking regularly (not just when thirsty) is prudent.

For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.

This follows post #8 rather than contradicting it.

Sodium: losing weight involves losing some sodium. Electrolyte drinks or salty foods help maintain sodium balance. Very low sodium intake on these compounds raises orthostatic symptoms risk.

I read post #10 twice before replying, because I had assumed the opposite.

Potassium: similar to sodium; losing weight involves some potassium loss. Bananas, sweet potatoes, and other potassium-rich foods help. Severe depletion is rare but symptomatic (weakness, palpitations).

Sodium: losing weight involves losing some sodium. Electrolyte drinks or salty foods help maintain sodium balance. Very low sodium intake on these compounds raises orthostatic symptoms risk.

Potassium: similar to sodium; losing weight involves some potassium loss. Bananas, sweet potatoes, and other potassium-rich foods help. Severe depletion is rare but symptomatic (weakness, palpitations).