Develop an interest to improve willpower

How do I stick to healthy habits (diet, discipline, exercise, and mindset) that I’ve broken for the last year?  

"If my diet interest can arrange for me not to get too close to ice cream, the discounted prospect of ice cream may never rise above the discounted prospect of the rewards for dieting, and the diet interest will effectively have won.  However, whenever the value of ice cream spikes above that of dieting, the ice cream interest may undo the effect of many days of restraint." - George Ainslie, Breakdown of Will

For you to be able to stick to healthy habits in diet, discipline, exercise and mindset, you should develop an interest in them. You should also devalue the things that get you offtrack.

Do develop interest in diet, discipline, exercise and mindset, keep learning more about how you can take them a notch up compared to what you are currently doing. Theres always new information and research constantly coming out. By reading about things that you want to do, you reinforce your current ways and stick to them.

Lucky for you, you can write down all the situations and things that made you stray in the last year. Collect those and put them in the DONT list and also how you will tackle them when they happen next time.

Create a dossier on all the habits, whats working, whats not working. You can then always come back to see how you stick to some goals better than others and modify it or use it for other new goals.