Dictionary.com defines habit as a noun meaning specifically:

"An acquired behavior pattern regularly followed until it has become almost involuntary." 

Wikipedia goes on to say this:

"Habitual behavior often goes unnoticed in persons exhibiting it, because a person does not need to engage in self-analysis when undertaking routine tasks."

Essentially, a habit is something you do for no reason other than the fact that you always do it.

Sure there are reasons to start forming a habit, like to be conscious of what you're eating or to get out and exercise, but really, it's only considered a habit after it's become automatic.

It's an action or behavior that you do to exercise self control and willpower before that; and that said, it's extremely difficult to break old habits and, subsequently, form new ones.  

Why is it so hard? Because it requires a substantial amount of dedication and conscious forethought to establish a given behavior as a habit. It takes practice.

There have been so many varied reports on  how many days or repetitions it takes to form a new habit that, to be honest, nobody's really sure just how long it takes.

A good estimate is about a month of repeated behavior before it starts to become automatic.

So, as it relates to weight loss, anyone considering making a substantial lifestyle change should, first, find their reasons for change, then form a solid goal for their efforts, and then plan accordingly for the formation of new healthy habits.

I've said before that it takes a few weeks of pain to form a new habit and that seems to be backed up by this research.

So why are habits important when it comes to weight loss and substantial life changes?

Essentially this, most of what we do during the day is some form of an already established habit. Whether it's eating chips and drinking sugary soda with lunch everyday, or taking a walk after dinner, these behaviors have been enforced in us from, possibly, years of repetition.

In the case of the after dinner walk, that's a great habit and should be kept up, which is easy at this point because it's basically automatic.

But in the case of the chips and soda at lunch, that's a not so great habit because it's high calorically and not very nutrient rich. This habit probably should not be kept up, but that's hard because it takes conscious effort to say no to using those things when you're making your lunch.

Every choice you make has the potential to become a habit if you make that same choice often enough.

And a choice can be either healthy or detrimental.

The very first time you make a healthy choice will probably be the toughest time, but every subsequent time you make that healthy choice, it will be easier and you'll feel a tiny bit better about yourself.

If you continue making that same healthy choice every time the option arises, it will eventually become almost automatic to make it.

Making healthy choices is what you do now, it's your thing.

Habits are what make losing weight and changing your life easy.

They are what drive the mechanisms of your body to make the right choices consistently and without thought.

But like everything, they take time.

That time may be hard for a while but I guarantee it will get easier and less and less thought will be involved in how you operate as a healthy human being. 

In summary, my advice? Just stick with it, no matter how monotonous, seemingly unpleasant or hard it seems, it will eventually become second nature and you will eventually be a healthier person. 

Just stick with it.