1. Sit ups burn almost no calories.
2. There's good carbs and bad carbs. Try to get more good than bad. Refined = bad, whole grains = good.
3. Meat is NOT unhealthy. Take more, but avoid the fried/sauced varieties as much as you can.
4. Tip: No sugar is the biggest way to cut calories. Coffee kosong, tea kosong, no milo, nothing except pure sugarless drinks. That means no fruit juices either.

I used to weigh 108kg/40-inch waist, now 77kg/32-inch waist, so I definitely know what I'm talking about. In the end it's up to you how to proceed, this is just my opinion.

Oh hello Andrew. Yeah I'm too bored (off topic).

Ok, back to the point. You need lots of protein daily. The body doesn't function on a "per week" basis. In fact when it comes to protein, it's more to per hour than per day, because your body doesn't store amino acids. It uses it up either to produce glucose (gluconeogensis) or tissue generation/repair (muscles and healing).

If you wanna go strict and heavy workout, you can lose EASILY 1kg per week. 3 months to lose 6kg is a breeze if you know what you're doing.