The reason most people cannot maintain transformative behavioural changes has to do with the way the human brain works. The reason we have habits of any kind is that there's usually a reward for the habit. When it comes to food, it is the pleasure senses that are triggered after a satisfying meal or treat.
Sticking to a healthy diet may not trigger the same pleasure senses so you must create a different reward. If you have medical issues, such as high cholesterol or have been diagnosed with cardiovascular disease, the reward should be something that shows your progress in improving your health.
Diet - to cheat or not to cheat - it will show up on your blood test, so schedule a blood test every 2 to 3 months. The blood lipid values are very sensitive, so wanting to see them improve with each test will encourage you to stay on track. We are all competitive, and once you have experienced the elation of seeing your lipid values improve, you'll be hooked. As your lipid values improve, you can start weaning off some of the medications. That's a reward.
Exercise - we know we have to do this regularly because it too will reflect in your blood work and your need for medications. So how do we have a more immediate reward for exercise?
Get a Fitbit, or any other exercise tracking device that you wear. Walking is the easiest exercise and these devices have step counters. Target 10,000 steps daily to begin. As your fitness level improves and you hit your goal daily, increase it gradually until you get to 15,000 steps. Get the HR version which also tracks your heart-rate.
There's an app for your mobile phone or you can track it on the web. Either way it becomes addictive and you don't want to fall below your targets so it motivates you to keep moving. As you exercise your heart muscle becomes more efficient so your resting heart rate also begins to fall. This is another reward for the exercise habit. There's also a place on the app to track your weight. Weigh yourself once per week and enter the value on the app. This is another motivator to stick to your diet and exercise plan.
Go to a place to get your body fat measured. This too can be entered on the Fitbit app. Get the body fat measurement every 3 to 6 months. You want to improve don't you? You don't want to see failure on the app, so you are motivated to stick to your health plan.
"The 3 R’s of Habit Change
Every habit you have — good or bad — follows the same 3–step pattern.
Reminder (the trigger that initiates the behavior)
Routine (the behavior itself; the action you take)
Reward (the benefit you gain from doing the behavior)"
Quoted from the book, 'The Power of Habit' by Charles Duhigg. (Great book, I strongly recommend you read it).
In summary, create an accountability and reward system for positive behavioural change, by tracking the impact of a healthy diet and exercise plan.
I'm living proof of this process. Male aged 54, triple bypass in March 2015, followed by angioplasty, and 4 different medications to take daily. Behavioural change and I've lost 35 lbs, am in the best shape of my life, and no longer require ANY prescription medications. I play ice-hockey every week in the winter and do High Intensity Interval Training 4 days per week.
If I can do it, so can you.
Good luck.