I am wondering what is the difference between these sentences? Do they have the same meaning?
I cannot eat meat.
I can not eat meat.
I can eat no meat.
I've seen such sentences as:
I can eat no meat but still be healthy.
But can I also use the "can do no" form in other situations, in case where I would normally use "can not do"?
I cannot eat meat.
I can not eat meat.
These only differ in spelling. Sometimes "cannot" is one word and sometimes two. In either case, it means "to be unable to"
Thus,
I cannot eat meat
means
I am unable to eat meat
The last one:
I can eat no meat
is a less common phrasing. It can mean the same as the other (inability to consume meat) or it can mean the subject is able to avoid eating meat. This difference may be clearer with context:
I cannot eat meat for a week
I can eat no meat for a week
The first says for a period of a week, the speaker is unable to consume any meat. The second says for a period of a week, the speaker is able to survive without eating meat. The difference is essentially what is negated.
With other verbs/objects, the meaning can differ from the other form:
Example:
I can't do wrong
versus
I can do no wrong
The former expresses an inability/prohibition on doing wrong things.
The latter expresses that nothing the subject is able of doing is wrong.
In your example of "I can eat no meat and still be healthy" "I can eat no meat" doesn't really mean the same thing as "I can not eat meat". If I am correct, they are saying that they are able to stay healthy even without eating meat. If you said "I can not eat meat and still be healthy" that doesn't mean the same thing. The first says that they are able to abstain from meat and retain health, while the second says that they are not able to retain their health if they do eat meat. Ultimately, the problem is that you should say "I can abstain from eating meat and still be healthy." Hope this helps.
