Jim Hallowes's HighlySensitivePeople.com:
We've learned highly sensitive persons or "HSPs" make up 15% to 20% of the population. HSP's nervous systems are different and are more sensitive to subtleties in their environment, which can be a good or bad thing. And because they process and reflect upon incoming information so deeply, they are more likely to become over stimulated and overwhelmed than Non-HSP.
According to Dr. Elaine Aron, author of "The Highly Sensitive Person" and "The Highly Sensitive Child", the Highly Sensitive Person (HSP) has a sensitive nervous system, is aware of subtleties in his/her surroundings, and is more easily overwhelmed when in a highly stimulating environment. Additionally, she says, the success of The Highly Sensitive Person is cause for celebration: "We've done it ourselves. And not surprisingly, since we are 15 to 20 percent of the population - that's fifty million in the United States. Highly sensitive people are real, we exist, and we've proven it. That alone is something to celebrate."
Fun and quick self-test called "Are You Highly Sensitive?" on Dr. Aron's web site.
The following quote from Thomas Eldridge's Being Sensitive In An Insensitive World might surprise you:
HSPs are very sensitive to food and physical environments. Food needs to be looked at from a different viewpoint than what is promoted by national food guides. Not all foods are going to be equally tolerated by their body. Stimulating substances such as alcohol, coffee, sugar and junk food can be highly toxic to an HSP. Diets need to be tailor-made and regularly modified. There are no right diets that sensitive people can follow permanently. Their level of sensitivity is anything but static and rigid. It requires a change in attitude to accept the fascinating refinement process continually being experienced by their body/mind/spirit. Generally, simple, frequent meals work best.