You are going to have to measure what you are eating to know how to log it and making sure that it is not going over. Fruits contain a lot of sugar and not as healthy as they say it is let me be frank.
I personally use mynet diary ( Use my code: PRVEYV ) to help me throughout the day. It allows me to log my snacks, my breakfast, lunch, dinner along with my exercise, my steps and water. I can also log my weight and there are also recipes that I can use when I run out of ideas to cook and make.
It also takes being active. Something that gets your heart pumping but not something that gets your legs or body burning. You need to be active but not as active to hurt yourself. So something like mall walker or walking anything for about 15-30 minutes a day.
I just got a vibration plate, a weighted hula hoop and a stepper to help me with being active and working out. I also got a jump rope, a peddler and I have an app I have found called Lazy workout and Just fit that I can do from my bed and or couch.
Just fit gives you a workout, one that you can feel and I love it. It has you lined up for daily and you will work pretty much every part of your body just from your bed alone. It is worth checking out and is now my go to. It will get your heart pumping and all it takes is just 7 minutes to do.
However I cannot put to much on me because I still am not healed from surgery and so I have to take it slow but even doing a little bit can actually help out a lot.
Being disciplined means saying no to a lot of things. It means sticking to your diet and goals no matter what is going on around you because at the end of the day, it is going to be you and disappointments trying to reach you're goal so once you set a goal and put your mind to it, you will eventually reach it.