1/ no true.However if you run or do any strenuous exercise before bedtime will make you hyperactive,hence your sleep time will be affected.

2/ yes,it's really that straight forward,however the type of calories do make a difference on your performance.

3/ If you intend to lose 1000cal a day,it would be advisable to loose 500cal from your diet and 500cal from exercise.
    As a rule of thumb,cal intake should not be below 1000 cal.
  To get a better idea of the amount of calories that you need a day to lose weight,check out the app Fitness Pal.Have fun

Firstly you don't need to master them,just be aware of them will do.

If you cut down 500 cal per day,you will lose 1 lb per week.( so do the maths )

I don't see the relation between losing one's weight and being able to win a 15km race.
I suppose if you want to do well in running,so just practise your running.

To lose 5kg in a month is pretty drastic.It can be done but at the expense of what? you have to consider the consequences.

Assuming you need 2500cal/day base on your height and your lifestyle.
Cutting down between 1000-1500 cals is ok.But remember half or at least a third of that must be with exercise.
Like I say as long as you maintain you daily intake,after minus the cut in your food and from exercise is above 1000cal,than it's still healthy.

Firstly you don't need to master them,just be aware of them will do.

If you cut down 500 cal per day,you will lose 1 lb per week.( so do the maths )

I don't see the relation between losing one's weight and being able to win a 15km race.
I suppose if you want to do well in running,so just practise your running.

To lose 5kg in a month is pretty drastic.It can be done but at the expense of what? you have to consider the consequences.

Assuming you need 2500cal/day base on your height and your lifestyle.
Cutting down between 1000-1500 cals is ok.But remember half or at least a third of that must be with exercise.
Like I say as long as you maintain you daily intake,after minus the cut in your food and from exercise is above 1000cal,than it's still healthy.

I think you're getting too technical.

As Nike say,"Just Do It" and have fun.Rome isn't built in a day.
If you lose this 15km race,learn from it and kick ass the next time!

a dilemma....

to be better at running, just run more.

run more is a thing. reducing body weight (fat) is another thing. It's like one person running while carrying a heavy bag vs carrying nothing - according to my friend, a runner. I'm a nooby, lol.

on 21 Sep (2 weeks ago), I went to CF for measurement. My weight was 71kg (body fat mass 17.1kg) while my height is only 165cm (BMI 26.1 - fall under obesity. shit. lol). After about 2 weeks control my calories intake and exercised, my weight measured last night at 66.4kg (body fat mass 12.4kg). The reduction of my weight (4.6kg) solely come from lower body fat (4.7kg), with additional of 0.1kg minerals. However, both measurement were pretty unfair because the first one measured after my lunch while the latter measured after the workout. 

but you need proper nutrition and rest time for the leg muscle to develop........

no doubt on the nutrition. I need to study further about this. For the rest time, maybe I force my body to much now. This morning I run about 6km, can feel a bit discomfort on my right knee. I had my acl operation end of November last year.

not easy with calorie restriction.
yes, it is not easy. I wont do it for long run. Just temporary action to reduce my weight to 63.6kg, as suggested by the machine. Lol, I trust machine on this. lol