What would you determine as not dieting so strictly then?
A sane deficit of balanced foods that is more of a lifestyle than a diet. The more weight you have to lose the higher your deficit can be and the less weight you have to lose, the lower your deficit should be.
This is not to say a person with a lot of weight MUST use a big deficit. They simply can if they are willing and able.
Anything aside from this, in my experience, isn't going to work. The other things are simply temporary solutions to permanent problems.
There are some very strict diets out there that utilize tactics to get the weight off fast. Most everyone is not conditioned (in terms of psychology or the knowledge) to go about them properly. When this is the case, the net outcome is frustration and lack of results.
Well, I'm about 5'6, 143lbs. I am sedentary most of the times, but eating 1300 cal works. I'm basically wondering if I can keep this up untill I'm at least 130 lbs?
Define "works?"
1300 calories actually isn't all that bad for someone with your stats.
You then have to look at what that 1300 calories is comprised of, which is critically important as well!
Will this deficit carry you to 130 lbs?
Who knows. It's hard to say, each person's metabolism responds uniquely. But don't worry about that. Expect plateaus and then you won't be shocked when they inevitably come along. When they do come along, you can handle them accordingly.
Also, if you start extra excercise, how would that help, as you would have to eat more calories anyway, to prevent yourself from not consuming enough calories.
Exercise contributes to the deficit.
So for example... if you need 2000 calories to maintain your current weight, you would lose weight if you dropped your daily intake down to 1500. This deficit comes entirely from diet.
If you added exercise to the mix, you could maintain that same deficit from above by eating a bit more. Suppose you burn 250 calories per day via exercise. Well now you can afford to eat an additional 250 calories per day, again, assuming you're shooting for that same 500 calorie deficit.
There's much more that exercise offers beyond the contribution to the deficit.
I mean, anyone using that thing between their ears wants more than to be thin. They want to be healthy, strong and capable too.
Things like resistance training tend to help 'persuade' where you lose weight from. Without it, you're more likely to lose muscle while you diet. With it, you're more likely to lose predominantly fat and preserve the muscle.
Not including things such as resistance training is one of the primary places (especially women) go wrong in their programming. They focus solely on the scale and then they end up a lighter, still soft version of their former self.
If you're going for the soft look, it's not as important.
But even if you are... there are a lot of health benefits associated with this sort of exercise that go well beyond the various physique enhancing qualities.
. Are you a personal trainer or something?