Do you think eating healthy and exercise will help prevent serious illness?

Not by themselves. Avoiding risky behaviors, get regular check-ups, immunizations against disease, practice good hygiene and getting proper rest are factors we can control that are no less important. 

Majority of the time, yes. Unless you're in the very small minority with serious conditions that are uncontrollable, non-treatable, or extremely rare condition where you're the one in 10,000,000 to have it.

And it's not eating healthy, eating less alone does wonders to improve one's health unless you're underweight. Unless you develop a deficit of a certain mineral. An average person eating 1500 calories of Mcdonalds a day would be healthier than a person of the same weight eating 3,000+ calories of vegetables a day (if that's even physically possible)

It can lessen the likelihood of it, but not give you a 100% guarantee against it.

Sure, they'll help; in fact, they're basic to the healthy lifestyle. Just remember that they won't keep ALL ailments at bay.

Nope. Just makes you less likely to get what ever is killing people the most.

I think, yes, if we keep eating healthy food and doing exercises every day, at least, you could prevent diabetes or cholesterol etc. But we have to check up every year, it's important to know how's going on our health?.

Help prevent some illness, maybe. In the event that you do become ill, living that lifestyle will make your illness somewhat easier to deal with because your body and mind will be in a better state to start with.

For some people, to a certain extent, Yes. We, being imperfect, will have to deal with some sort of health issues, some more serious than others. However, moderate but consistent exercise—some recommend three times a week—strengthens the heart, improves circulation, lowers cholesterol, and reduces our chances of a heart attack. More than that, exercise promotes a sense of well-being, likely because of the endorphins that are released during strenuous activity. Therefore, balance are needed with both activities of eating healthy and exercise.

Also Yoga, and learn how to reverse your

center of gravity. Yoga for life but,

only if you want to live longer.

No one is guaranteed a healthy life. But following certain guidelines -- namely, eating well, exercise and and not smoking can do a lot for you.

• Healthy eating prevents obesity – the number one nutritional reason for disease.
     
     
• Certain nutrients affect certain parts of the body.

• Healthy
  eating improves the mood, which in turn boosts physical activity.

• Healthy
  diets boost “good” cholesterol (high-density lipoprotein) and decrease
  unhealthy triglycerides.

Make fitness a part of your daily life. A good goal is 150 minutes of moderate excercise each week. You can break that into five sessions if each session lasts
for 30 minutes. Or you can do it for less time, as long as you make your
activity more challenging. Any activity that raises your heart rate counts. It could be brisk walking, sports, housework, or yard work.