Wow, I apologize for not responding -- I thought this did not post, as my computer had rebooted before I thought it posted.
buglady -- I do have fructose malabsorption, not intolerance, so my condition is less severe, but still a notable issue.
In response to your questions:
1. It mostly depends on the ratio of fructose to glucose. For example, apples have a very high amount of fructose and much less glucose, so when they combine into sucrose, there is much more "free fructose" left over, which causes the problem. Foods that are known fructans are more troublesome, though. There isn't a lot of information about malabsorption because it isn't as commonly diagnosed and people have different tolerance levels, just like people who have lactose intolerance.
2. I can't digest it properly, so my symptoms cause my to feel awful all the time. During my year-long journey to a diagnosis, I was all kinds of sick. I have severe gas and other gastro problems (often including diarrhea, vomiting, and making a very bizarre gurgling sound every 30-60 seconds), my stomach hurts all the time, I have severe headaches, I break out and bloat (that year of figuring things out, I fluctuated between 4 pant sizes, depending on the day). I sometimes get a bit itchy. I also know that there is a link between depression/anxiety and fructose malabsorption. As someone who already suffers from severe depression/anxiety, it's just another reason to avoid the food. All of these symptoms combined, it makes it incredibly difficult to function day-to-day.
3. When diagnosed with FM, I was put on a very strict fructose-free diet. During this time, I did eat for an easier transition and to avoid being sick due to nutrient deficiency, etc (I was in high school in a very small town with very few vegan resources at the time. It was hard enough without the FM. The ease was important to me). After 6 weeks on the very strict diet, you are encouraged to slowly introduce possible trouble foods to test your tolerance to them. For example, I tried to reintroduce garlic and tomato-based sauces first. Once I found out what I could tolerate in small doses, I began to get complacent. I could realistically handle half a banana every other day if I didn't eat a lot of other moderate trouble foods, like tomato-based products or products with sugar that wasn't specified as 'cane.' However, I would eat a whole banana, along with spaghetti sauce and brown sugar all in one day and do something similar the next. The immediate symptoms were mild enough to ignore. However, one can develop a build up in the intestines. In fact, when I was first diagnosed, I had gone so long not knowing that I had a bacteria overgrowth in my intestine that I needed medication for. Without being able to digest the small amounts of fructose in the foods, it can build up and worsen the symptoms. By resetting, I'm referring to going back to the very basic, strict diet I was on in my first 6 weeks.
Wow again. Sorry for the lengthy reply -- terseness is not one of my strengths, I suppose, haha.
ElaineV: I have looked at the website! The only difficulty I have is that the blog writer has probably worked their way up to being able to tolerate some of these foods. For example, they use a lot of peppers and zucchini and sweet potatoes, all of which have been restricted in all of my research and personal experimentation. Some of the recipes I definitely want to look into once I begin to reintroduce though!