one possible version；
Dear friends,
As we all know, we are what we eat. Therefore, it’s very important for us to form healthy eating habits.
However, bad eating habits are still very common among us students. Some of us often go to school without breakfast; some like to have snacks; some others are particular about food; and still some eat or drink too much. All these bad habits will surely do harm to our health.
To keep fit, we should have various healthy diets, which generally include proper amounts of fish, meat, vegetables, fruit as well as main food. Besides, we’d better have meals regularly.
In my opinion, we should try to develop healthy eating habits to build up a strong body. Only in this way can we have enough energy to study better.
That’s all. Thank you!

略

one possible version；
Dear friends,
As we all know, we are what we eat. Therefore, it’s very important for us to form healthy eating habits.
However, bad eating habits are still very common among us students. Some of us often go to school without breakfast; some like to have snacks; some others are particular about food; and still some eat or drink too much. All these bad habits will surely do harm to our health.
To keep fit, we should have various healthy diets, which generally include proper amounts of fish, meat, vegetables, fruit as well as main food. Besides, we’d better have meals regularly.
In my opinion, we should try to develop healthy eating habits to build up a strong body. Only in this way can we have enough energy to study better.
That’s all. Thank you!

略