If you do two hours (or ten!) of Combat a day but still eat more than you're burning, no amount of exercise will have you lose weight. Diet truly is 90% of the equation, that's where you need to really scrutinise. The other issue might be that you'll injure yourself exercising too much.

Weight loss truly is just math. (Perhaps being an engineer you'll like that ) Calories in must be < Calories out. You can think about it like this:

Your base metabolic rate (how many calories it takes your body just to exist - even if you don't move all day. You can find a number calculators online that will help you estimate this based on a number of factors.)
+
An amount of calories that covers the basics of what you do in a day (walking to and from the car, sitting up)
-
Calories you burn in exercise
=
Calories you must EAT LESS THAN to lose weight.

Which means ... you need to figure out your minimum caloric intake for a day (what you need to survive and for fuel!), what you're burning additionally on top of that, and try to eat say, 300-500 calories less than that per day. Burning 1lb is approximately 3500cal. So if you can balance so that you're burning 3500 calories more than you're eating in a week, you should lose approximately 1lb each week. (It'll range ... perhaps 0.5-2lb/week.) 

I did a quick calculation for you. Your BMR is approximately 1500 calories/day. Now keep in mind that's literally to survive. Let's say you aim to eat 1600-1700 calories a day, but you want to ensure a 500 calorie deficit per day. So if the minimum you'll ever eat on a day is, say, 1600 calories, and you then burn 600 calories at the gym, you could actually have a 100 calories extra in food since you want to have a -500 calorie deficit. 

You also need to figure out the calorie content of everything you eat by keeping a food journal. And accurately figure out how many calories you burn in exercise. I'd recommend a calorie-counting heart rate monitor for that. It's still an estimate but it's a better one than, say, an online tool.

My recommendation? If you're serious about this, join a group like Weight Watchers. They have a program that has simplified calorie counting, they guide you on what the right food intake is for you and allow you to take into account exercise you are doing, and because you cook your own food and put it together, it actually teaches you healthy eating. They advise what foods you should be eating etc (i.e. don't fill your day's worth of food with absolute crap - instead eat nutritious foods.) Plus you have a whole support system and people to ask questions to. Between that, and your time at the gym, it will pay off.