Congrats on your first step to lose weight. Better start slow than never right. No worries, we are here to guide you. First of all, I believe that is water loss. Fat loss won't go easy with you in just few days.
On your diet, I fully understand that reducing portion is not that easy. So what I am suggesting that you try to avoid oily food AT LEAST. And try to replace any drinks with just plain waters. With those two tips, would greatly help you losing weight for the first 10kg. And maybe another 10, or maybe another more 10, depends on your target. Fruit and bread during lunch is not a good option. For lunch you must have protein source, carbo, and veggy (fiber) and yes again please avoid oily food.
On your workout, Incline threadmill is good, keep up the good work. And if possible try slow jog without incline or a start.
Sit up is not recommended for you. Do crunches instead as others have recommended in previous post.
And 1000 crunches is not impossible. Divide the 1000 rep with upper crunch, side crunch, etc (Google is your best friend, search for type of crunches) and further down to do it by after you woke up, morning, afternoon, evening, night, etc. For your weight training............................................................................................. (Google still your best friend. Use it)
Consistency is the key dude. If you not consistent you'll never achieve good.
Owh, and yes.. Please please and please don't do spot-reduction. Do the training, spot later.