Edit: I suppose my primary goal in all of this is longevity, and as such, I'd like to stack the deck in my favor to the greatest extent. I have mechanisms whereby the DNA damage from ionizing radiation produced by diagnostic x-rays can be repaired. Does this mean that I should be cavalier about x-rays and radiation in general simply because my body is robust enough to handle the occasional x-ray? No, I'd rather avoid them unless I break a bone or something so I have that much more chance of not developing cancer. This is the same motivation that leads me to cook meat at low temperatures. It's not going to kill me today or tomorrow if I don't, but who knows what that effect is over decades.

20g of fructose a day doesn't sound like a lot, but that 15g difference over 80 years is 438,000 grams of fructose. That's a lot of AGEs. I rather think that makes a difference.

Those saying "you'll have to pry the fructose from my cold, dead hands" may be creating something of a self-fulfilling prophecy.

It is my belief that fructose is the most lipogenic naturally-occurring substance that we encounter. There's a whole host of problems ranging from adiposity to dyslipidemia to the creation of AGEs. These are obviously much worse with large amounts of unbound fructose, as occurs in products containing HFCS. Honey also technically has a large amount of free fructose, but there are other factors that supposedly mitigate that fact. If I were working for a pharmaceutical company and was tasked with creating obesity in a pill at low cost to the company, I would just make a pill that was pure fructose. That's one sugar pill that wouldn't be a placebo.

I'm of the opinion that we should count fructose as being more of a dense carbohydrate inasmuch as lipogenesis is concerned. I'm not sure how to fully quantify the effect, but I count grams of fructose as 3-4X that of starch. While it's true that insulin will store extra glucose (that which can't be stored in muscle or the liver as glycogen) as fat, there is just more going on with fructose.

I think this is an excellent piece about how we've evolved alongside fructose: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2917125/

I get only what fructose is in spinach and potato currently because I feel that the best "bang for your buck" when it comes to fat loss comes from first decreasing fructose as low as possible, then decreasing starch to where it is supplying only enough glucose to replete glycogen stores.

There is no minimum daily requirement for fructose, and really, any amount of it will be more toxic than the equivalent amount of glucose.