First off, they ate SEVEN TIMES the amount of fruit compared to the swedish norm. That's not a little bit of fruit. That's enough to make up a significant portion of their daily caloric intake - in fact, they ate more weight in fruit than anything else. They still consumed about 130g of carbs/day, almost exclusively from fruit. Waist circumference decreased by 21% in association with increased fruit intake. That's a lot.
Second, I have seen the studies comparing added sugar foods (candy) vs. natural sugars (fruit) and their insulin and glycemic responses. Yes, they produce the the same glycemic response. One example here -->
Cambridge Journals Online - Abstract
But this is where almost everyone who looks at glycemic response makes a serious mistake - it's what happens after the glycemic response that dictates real life health outcomes and the risks associated with an increased glycemic load. Glycemic load in a vacuum means nothing - it's whether or not vascular damage, CVD risk, inflammation, and glucose intolerance increases over the long haul. High glycemic load
can illicit a negative inflammatory response (namely by upregulating inflammatory agents like TNFa). It's not
will, it's
can.
Here's an example from a diabetic meal response study:
ScienceDirect.com - Journal of the American College of Cardiology - Postprandial endothelial activation in healthy subjects and in type 2 diabetic patients: Role of fat and carbohydrate meals (let me know if the link works, I accessed through my uni portal so it might not work).
Here's a brief summary of the study, I'll just discuss the relevant portion. They took their diabetic group, who had an inflammatory response to both high-fat (didn't say what it was, but it was 58g carbs and 50g fat) and high-carbohydrate meals (cheese pizza, 144g carbs and 17g fat). Then they measured the inflammatory response to those meals and recorded the changes from fasting, to 2h and 4h postprandial. Then a few weeks later they gave them the same meals, but included a vitamin/antioxidant supplement of Vit E and ascorbic acid. The results?
When vitamin supplementation accompanied the high-fat or pizza meal, there was a significant reduction of the rise of cytokine and adhesion molecule parameters, with values that were significantly lower as compared with those recorded following the meals without vitamins (TNF-α, p = 0.025; IL-6, p = 0.035; ICAM-1, p = 0.016; VCAM-1, p = 0.04) and not significantly different from baseline (Table 2).
Fruits naturally contain high levels of various antioxidants and vitamins (varying on the fruit of course, but all fruits contain something). An increased glycemic response alone doesn't mean anything. It's the impending result of that glycemic load that means something. In the context of antioxidant and vitamin dosage, that glycemic load has negligible impacts on inflammatory cascade normally associated with higher glycemic loads.
And this should go without saying, but we have barely understood what exactly is in most fruits. Almost every fruit has different compounds that are beneficial in different ways. It seems like every other day I see a new article out about how X fruit has new Y compound that is beneficial for Z symptom.