In order to maintain a healthy body, Islam offers a diet that still is used & recognized by today's standards as very sufficient. 

There are four things which Islam has declared unlawful and forbidden. They are: wine products, animals found dead, blood, and anything edible credited to in the name of any one besides Allah.

Also, birds and all carnivorous (animal that eats meat) animals are also forbidden. Water animals are halal even after perishing. Other forbidden substances include: anything that alters one state of mind.

For example is alcohol or drugs. A good way to see what kinds of products are being sold is to read the labels on the cans and food packages. Most of the companies that sell food products offer a toll free 1-800 number for those inquiring about food content.