What are the effects of losing water weight? Dealing with excess fat?

Starting working a job 5 weeks ago that requires me to constantly be around heat. I weighed in at 242 and now am at 225 pounds. Due to working in the heat I've also begun drinking plenty of water, more than the recommended minimum which I can definitely confirm helps satiate hunger and also have cut down to 1 to 2 meals a day but still skipping breakfast. I've been looking around online and I believe all the weight I lost was water. However my body is starting to tone at least I think that's the appropriate word to use in the situation. I'm starting to feel less fat on my arms and in the abdomen region. About 3 weeks into my job I now have bowel movements more often and occasionally get headaches just curious if any of this is related.
What are the effects of losing water weight? Dealing with excess fat?
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