The meaning of the phrase "It's a stretch"

[Unregistered]

I was watching a news coverage this morning on Kellogg's claim that their coco puff help boost kid's immunity system. Apparently this claim has irked many critics. My question is, there is this one sentence that i have diffculties with. It goes like this, "it's really a stretch to say that a handful of vitamin put into the cereals has immunity boosting benefits." I know it's not an exact quote of what the food magazine editor said. But could anyone tell me what the meaning of the phrase "its a stretch" is and possibly give me another example of how to use this phrase. Many thanks in advance!

 

[DougLewis]

"Its' a stretch" is an expression used to describe an unlikely achievement.

It is a sarcastic comment often used to insinuate that one would need to stretch their imagination to believe what one is being told, or that the teller stretched his imagination to come up with the claim.

"It is a stretch of the imagination to believe that."

Often the claim seems embellished.