The advantage of eating a nutritionally engineered product is that your body will be provided with all the nutrients that it requires. If you choose to eat balance diet nutrition, you will have to combine a lot of food before you get all the nutrients your body needs. And you may not get all the nutrients your body needs if you don't eat the right food and the right quantities.
The disadvantage of the engineered product is that your body may not get the required quantity of nutrients it needs since those engineered products are not in their natural form. Another disadvantage is that you don't have the freedom of choosing what you desire to eat.
