Should a person with fructose intolerance avoid any and all sources of fructose? The answer to this question depends on what type of fructose intolerance the person has.
Hereditary fructose intolerance (HFI) is a genetic disorder, and is not the type of fructose intolerance that some people with IBS commonly have. Individuals with HFI should not consume any fructose at all, no matter how small the amount. Many individuals with HFI are diagnosed in infancy or childhood, when caregivers not the child is violently ill after ingesting anything containing fructose, such as table sugar, fruit, or honey. Rarely, adults have undiagnosed HFI; they have an absolute aversion to sweet food of any kind, going back to chilhood. The "dislike" of sweets may run in the family.
If you have HFI or suspect you may have HFI, there are some foods on the FODMAP Elimination Diet you should not consume. Instead of proceeding with the protocol in IBS--Free at Last! you should consult your healthcare advisor for an evaluation.
Dietary fructose intolerance (DFI) is a term that describes the symptoms that some people get when they have fructose malabsorption (FM). To cleary distinguish their condition from HFI, many affected people prefer the term fructose malabsorption (FM) over dietary fructose intolerance. In my opinion it isn't as medically accurate to do so, since not everyone who malabsorbs fructose experiences uncomfortable symptoms. But still, if a patient tells me they have FM I know what they mean. Most people with DFI/FM can tolerate some amount of fructose. With the help of the FODMAP Elimination Diet, you may be able to figure out how much is too much for you.
More information about HFI is available from the U.S. National Library of Medicine.