"You are what you eat" Could you help me to correct this writing? :)

I am totally agree with the sentence “you are what you eat”, because I have read a little about it, and it seems we are like a glass of water, all substances that you take changes your composition, this is what happens to our cells. Then I will write the different ways I understand that phrase.
I understand “you are what you eat” in three different meanings. The first one is about unnatural medications. There are many studies which support that (or "there is much research which supports), if we ate only healthy food, most diseases would disappear and we wouldnt need artificial pills, because foods is our best medicine.
The second one is about fast food. Our forefathers were eating only healthy food for thousands of years, but later, this changed. Most of people eat a lot of fast food, which contains a lot of artificial dangerous components for our body, because it contains a lot of saturated fats, which produces heart diseases in a high percent of people who abuse of it. Moreover, most of the meat in fast food industries comes from animals fed with a lot of hormones in order to grow large fast.
The third and last one is about direct changes in our body after consumption of different types of food. Fruits and vegetables makes you feel slight and fresh after lunch, and you notice a lot of energy after eating them, however, when you eat fried food you feel heavy and tired. Furthermore, food gets very modified when you fried it, losing a lot of properties which our body needs.