Those studies that you talk about use very high levels of fructose (at least from all of the ones I have read). All of the studies that I have read also use isolated, unnatural, refined/crystalline fructose, which IS actually different than natural fruit sugar. In fact, fruit sugar, in it's natural form, should really be called laevulose (NOT fructose), where it is bound to other chemical compounds, canceling out any 'negative' qualities. When you isolate a chemical outside of it's natural biochemical sequence, it then becomes more like a drug, not a food, to the human body because the dependent qualities are lost. For example, we all know that benzoylmethylecgonine (cocaine) is a highly addictive substance. But why? Benzoylmethylecgonine is the alkaloid that is derived from coca leaves. This alkaloid is what makes the drug highly addictive. However, in the coca plant itself, this alkaloid is in it's natural state, where the addictive qualities are canceled out by other chemical compounds, therefore it is not recognized by your body as a drug like cocaine is. Go ahead, chew on some coca leaves. It's like drinking coffee and may southern American countries do that legally. It's nothing like loading up on cocaine. This is one of the most overlooked subjects in biochemistry and nutrition. People forget that not all harmful isolated chemicals are harmful in their original form of natural biochemical sequence. So, to say that laevulose (fruit sugar) is the same exact thing as highly refined, isolated, crystalline fructose would be wrong. That would be like saying cocaine is the same thing as coca or that heroine is the same thing as those poppy-seeds on top of that bagel in the market. Also, fruit is not the major source of fructose (laevulose) in the normal diet. Most people don't get much of it in it's natural form. In fact, only certain fruits are high in laevulose, while others are relatively low. Here is a list of foods that contain fructose (natural and refined), in descending order:
• High Fructose Corn Syrup (HFCS)
• Table Sugar, which is a 50:50 combination of glucose and fructose
• Brown Sugar
• Maple Sugar
• Cane Sugar
• Molasses
• Honey
• Concentrated Fruit Juice
• Fruits
• Vegetables
As you can see, fruits and vegetables are at the very bottom. Now factor in the simple fact that this is laevulose, not refined, isolated, crystalline fructose. Completely different than HFCS in both quantity and biochemical sequence. There is also another important fact that the "all sugar is created equal" crowed misses: Unlike glucose, laevulose is an insulin-independent monosachharide. In a healthy person, fruit does not spike blood sugar violently, like table sugar does. So, in other words, stay away from refined, man-made fructose, but fruit in it's natural form is fine. I think one of the most important thing some raw paleo/meat eaters often overlook is the need for antioxidants in todays environment.