Re: Is it possible to engineer foods that our body could make no waste of

The short answer to your question is no (at least for 99.9% of food). Now, I 
don't have any hard evidence to support this, but let me try to explain. 

The metabolism of food by the body is a series of biochemical reactions. The 
products of one reaction will be used in other reactions. Eventually, as 
products continue to be further metabolized, a waste product would be the 
result.  Since we (humans, I mean) are a carbon based system, many times this 
waste product is either CO2 or water. And, it doesn't make sense to me that 
foods could be created that would result in no waste products. For example, 
plants, which take in nutrients either at or close to their elemental level 
(meaning, for example, they absorb nitrogen from the ground, not proteins) even 
have oxygen as a waste product. And humans absorb complex nutrients that are 
then metabolized to give the elements the body needs for maintenance and growth.

So, like I said I don't have any hard evidence to support this, just an overall 
understanding of the metabolic processes of the human body. And, I'm not sure 
that this idea is what we would want. To get close to a "no waste" food, it 
seems that it would have to be a collection of elements, in some sort of 
capsule. That sure doesn't sound like a very good dinner to me.

Thanks for a very interesting question. You made me think this one through quite 
a bit.

Jill Irvin, RD
Ohio State University