REASON
I think first and foremost, you have to have a personal reason to want to be healthy.  There is no point in doing it for other people.  The reason has to be legitimate and a serious reason, otherwise it will be easy to go back to old habits.
KNOWLEDGE
A lot people eat just to fill a gap, but they don’t realise that food needs to nourish your body too.  (I used to be one of them).  Each and every cell in every organ of your body is affected by what you eat.  If your cells are not nourished and cared for, your body will not be happy.  Cells need proper nutrients in order for the body to perform at its peak.  We need to educate ourselves on the reasons to eat healthy and why it is so important.
ATTITUDE / RELATIONSHIP WITH FOOD
It is often our attitude towards food that is our biggest downfall.  We have to change our mindset about nutrition in order to make it work for us.  I think in the past, not enough emphasis has been placed on the importance of a healthy diet.  Too often we use food as an emotional crutch or an excuse for many things.  You can take control of your life and health by taking the step to change your mindset around food and nutrition.  It is a very powerful exercise!
MIND-BODY CONNECTION
The mind and body work in unison in absolutely everything.  With nutrition, it is often our minds that affect what we eat and how we eat.  Therefore it is of utmost importance to also feed your mind with good and positive thoughts in order for your brain chemistry to change for the better.  In the exact same way, what we put into our mouths affects our mental state.  Certain foods actually alter the chemicals in the brain and have an adverse effect on hormones and mental clarity.
REASONS WE FAIL TO MAKE LASTING CHANGES
1.     Feeling overwhelmed: too much change at once with a completely new nutrition plan
2.     Mindset – negative self-talk / limiting beliefs
3.     Knowledge and know-how: we don’t know how to make healthy food delicious and we do not know what to buy and how to put it all together. 
4.     We think that healthy food has to be boring and tasteless – this is far from true.  It is just about knowing how. 
5.     We overthink and complicate things
6.     We see it as a diet and not a lifestyle change: this mindset sees it as a hurdle to overcome instead of an exciting journey to long term health and vitality
SOLUTIONS
1.     Breaking bad habits: It is never easy to break a habit.  Your mind has to be strong in the beginning and you need to remember your reasons.  Once a habit is broken, it gets much easier and new, healthy habits are formed.  I promise you that your taste buds will aquire the taste for good healthy food and you will eventually love it!
2.     Keep it simple: Healthy food is simple and easy to prepare. It is much easier that you think it is and it can be delicious and nutritious. 
3.     Make fewer small changes over time: in order to bring about lasting change and continue with a healthy lifestyle for life, you need to make fewer smaller changes gradually.  Once one good habit has formed, you move onto the next one.  It takes time but is worth the small effort.
4.     Educate yourself on which foods to cut out and how you can make heathier meals for you and your family. 
 

Just remember, everything is choice!  Choose and happy, healthy future for yourself!  It is the biggest gift you can give to yourself.