Eat healthy and balanced diet for your good health and fight against the diseases.
Also do some proper exercise for your fitness purposes.
Do exercise regularly as much you can easily do. If you do exercise after a long interval for too much time, it can be harmful for you.
I agree with you. Do you know, Nutritionists use "diet" to mean all the food you eat. Diet is not just menus for a day or week, but your usual food choices over time. Many other people use "diet" to describe a plan for weight loss or a specific prescription.
Unfortunately some people think that "Diet is depriving yourself of something as long as it takes to be an ideal weight and then going back to eating junk."
Personally I like to think of it as more of "a healthy lifestyle change." It means, I've made the decision to eat more healthily. I am a healthy eater not a dieter.