If you want to be healthy, and I assume you do, then I have four words for you. Diet, exercise, hydration, and sleep. Without all of them in good working order, you will not be any healthier than a car that has plenty of fluids, except is oil. That car will not last, just like your body will not last.
They say you are what you eat, and there is some truth to that. If you eat poorly, you will have poor health. But more than that, even if you get plenty of exercise, drink lots of water, and get adequate rest, if your diet is poor, so will be your health. A healthy diet includes all food groups in the correct proportions. Your diet should consist of roughly protein, fruits, vegetables, and carbs. This is a simpler way than the food pyramid, food plate, or whatever they use these days.
To be healthy you also need to get enough exercise. The best combination is 3 cardio days per week, and 3 weightlifting days. And not just any exercise will do. I see guys at the gym all the time lifting weights, but never getting bigger muscles, women on the treadmills, never getting thinner, and one toothpick woman who never gets stronger. The reason is that the guys never push themselves by doing heavy weight or hard lifts, the fat women never go faster than a brisk walk, and the toothpick lady never lifts more than about 5lbs. You have to make it burn and keep getting better, stronger, and faster.
Your body is made mostly of water. 70% of you is H20, so you can imagine that drinking lots of it is kind of important. It turns out that it is, and that you will be much healthier with plenty of it. Almost every chemical reaction your body goes through to keep you alive and moving takes place in or with water and it wouldn’t happen without it. Getting enough can be tough though. The best rule to follow is to take 3-4 swallows of water every time you use the bathroom and drink plenty during and after workouts.
Lastly is sleep. This is the time your body repairs itself and gets ready for another day. If you don’t get enough, you don’t repair properly and consequences will follow. Don’t drink caffeine much either, because it will cause you to feel energetic when you are not. So it you are tired all the time and feel like you need a boost, try sleeping more instead of coffee. If you do, you will be a more healthy person.