Fructose is seen as a particular evil among carbohydrate sources, and in particular, in its purported role in worsening metabolic disease. Fructose is really implicated in raising triglyceride levels and therefore causing things like obesity and fatty liver.
I used to think that fructose was something we should really look to restrict, based upon reading a lot of bad things about it, although such things tend to be very one sided, where the objective clearly is to damn fructose as much as possible, and they do tend to portray fructose as the nectar of the Devil pretty much.
It was only when I noticed that fructose may be beneficial and therapeutic in my own diabetes treatment that I began to explore the notion that perhaps they are wrong about this nutrient, or at the very least, that it might not be as bad as they think it is.
As a diabetic, the first thing that comes to mind is how fructose may increase blood sugar, and I reasoned that whatever it does, it's got to effect it less than glucose would, because when we measure our blood sugar this is what we are measuring. So glucose is certainly going to put up blood glucose more than anything else, and as it turns out it indeed does, and fructose is preferable as far as impacts on blood sugar.
This isn't surprising really, although some people seem to go up from fructose somewhat, fructose though does tend to be better tolerated among diabetics than glucose is, and more so than sucrose, which is half glucose and half fructose.
I'm not a big fan of the glycemic index but I do think they get this right, where glucose itself is high glycemic, the highest, fructose is low glycemic, and sucrose is in the middle. With diabetics, glycemic effects do tend to become exaggerated due to our lower capacity to process carbohydrates, but in terms of comparison, glucose does indeed put us up the most, fructose the least, and sucrose is somewhere in the middle, being a mixture of the two.
It's not just that fructose raises our blood sugar less, it also has less of an effect on glycated proteins, which is what we need to be looking at as a proxy for seeing how much damage that too much sugar in our blood has. The A1C test, which measures the amount of glycation, or stickiness of red blood cells, is more than just measuring average sugar levels in our blood, it measures the effect of this sugar, and you don't want too much stickiness here because that correlates with microvascular and mascular damage, diabetic complications in other words.
So in this study they compared people eating fructose with other types of carbs, glucogenic ones in other words, and found that by essentially substituting fructose for glucose, their A1C was reduced by an average of about half a percentage, a very significant amount. So it seems that fructose is actually good for your blood sugar, which surely goes against the way a lot of diabetics think.
So perhaps the conventional dietitians aren't so far off after all recommending that we get a good intake of fruit as diabetics, although this being more correct then some may think is mostly out of ignorance, as the reasons they recommend this is for nutritional reasons, not glycemic control, although there is something to be said as well for the additional nutrients that fruit provide.
This does leave one very big issue though, and that's how fructose is processed and its purported role in worsening triglycerides, as well as other metabolic markers like uric acid levels. So fructose is vilified by many for this, for making us obese and in particular for causing fatty liver in particular.
If this is really the case though, then this is a big strike against fructose, and a very big one as this will tend to make our diabetes worse over time, fatty liver isn't something we want and this can increase insulin resistance and therefore increase our disease progression.
However, when you set aside the speculation and actually look at the studies here, and when you look to hone in on fructose and weed out confounders like excess caloric intake, it becomes clear that these concerns are at the very least grossly overstated.
So here's an abstract from an article for you where they have looked at long term studies of fructose, and sucrose in particular, and sugar containing beverages in particular, and did not find such risks. Whatever risk there is present with this also tends to be related to excess caloric consumption, and this actually makes sense as well if we think about it and we know a little about metabolism.
Excess energy will be stored as fat, and fructose is indeed stored as fat more efficiently than glucose is. This is really what it comes down to really, fructose is not only used as energy but it is more efficiently used as energy than glucose, and it's also more efficiently stored.
So there's no issue here so far unless you consume a lot of excess calories, and people who drink a lot of sugar sweetened beverages tend to do that, and there's a fair bit of calories in these drinks themselves, and they do have a much lesser effect on appetite suppression than eating solid food does, which is true with eating sugar as well.
Ray Peat even thinks that fructose is protective, even for diabetics, and makes a surprisingly good case of this in fact, something which is a topic for another day but his view that diabetics should use sugar as a therapy to treat their disease would seem preposterous to most people, and that would be the case if we were talking about glucose, but may not be as crazy of an idea as it first seems when we're talking instead about fructose.
Dr. Peat does make the distinction between fructose derived from fruit and fructose from grains, high fructose corn syrup in other words, which is clearly very unhealthy in anyone's book, but this is a different substance and does have a fair bit of starch in it and it's starches that we need to be most wary of as diabetics, much more so than fructose and even more so than sucrose.
So the bottom line is that eating fruit may not be as bad for your diabetes as some people think, I'm eating a lot of fruit now as well as drinking fruit juice, and even get a decent amount of sucrose now, and I am seeing some real improvements in my diabetes, and it may at least be something for people to try.