There is just no way any animal given a a constant choice of food that our modern system provides is drawn to the
same proportions of things it gets in nature. Looking at the larger world, certain 'modern' diets work better than others, and these have to do with compositions, quality and proportions which is unfortunately going to be left to peoples experiences and scrutinous examination of traditional diets and modern research. If we are talking domestic animals (arguably less deranged according to raw/hygienic thinking than humans) and feed them some religiously constructed diet of raw foods independent of how they should eat they certainly will eat it and WILL do worse than modern dogfood.
if one wishes one can easily poison bears, wolves, (omnivores and carnivores alike) with natural substances put in attractive food. If you can sneak outright poison into foods, certainly people won't use their taste to decipher how much fructose is taken in or how much internal fermentation or fungus or any other thing is being created unless the symptoms are addressed and analyzed. Often if people have internal inbalances they will crave what these imbalances crave. Likewise, protein will likely taste good regardless of whether it is causing long term problems or short term poor use for energy in comparison to fats (or complex carbs). Foods not even on the menu for religious reasons of course will not be craved or if so, not sought out. Your body doesn't seem to have an intelligence at all to respond on a day to day in any meaningful way, only adjusting here and there to our decisions to ensure our best survival - which is not thriving.
For me no matter how poorly my health was exacerbated by all natural raw diets all the culprits still tasted fantastic and could eat more and more of them as you point out. Its easy to rationalize ones feelings as ideal or as natural consequences if they aren't actually being tested regularly in that natural environment or even comparing them to other diets.
With fructose I do think this is A issue, I'm not sure if its the main issue and would even pose a more radical view than some other paleo theorists that even other high fructose diets will not necessarily have the same issues as high fruit diets. The idea that anything unrefined is harmless is clearly absurd. Whole families of humans could be killed by a 16 oz tonic featuring 100% belladonna and yet individuals can drink 16 oz of coke almost every day and some of these people end up like Clint Eastwood. With fruit there are even GI issues that come into play that aren't factored in with regular table sugar which absorbs quite differently.
I have noticed myself the higher fructose content fruits generally do seem to be the most problematic and this is pointed out by others as well. I know I've eaten most of the tropical fruits off the tree in a semi-wild (unsprayed) environment. In order to get at the best tasting fruit you
have to pick it at a certain point then sometimes still put it in a bag to ripen, otherwise you are picking from fermented fruits (which will from experience create more internal fermentation i.e. alcoholic spots on bananas) on the ground filled with ants and other insects. Most of these so called 'fruits of our origin' are not found in the plains but in jungles rampant with all kinds of scary small predators which seem to innately scare the shit out of humans. This makes the whole idea of 'easy access fruit abundance' where lone wanderer eating under a tree in blissful harmony quite absurd. Killing one animal can keep one full - back at base for weeks, that is when humans can garner energy from the fat of animals, which they undoubtedly are able and would have been required to do in nature.
Even looking at the composition of these things, durian, mango, jakfruit, the seeds are MASSIVE and yet these fruits are more specifically adapted to humans rather than fruits like berries where we can transport the seeds?? Oranges, limes, tomatoes, cucumber, gourd, guava, etc., are berries. These fruits or things like pineapple where the seeds are scattered on the outside, or fruits like papaya and breadfruit (a more starchy/fatty fruit) and squashes who have smaller softer and even more edible seeds also seem to be more sorted to being symbiotic with humans. Many of these are found in Africa and even these fruits are smaller in nature, less sweet and difficult to get in quantity. Is it no mystery that people generally do better on these fruits, particularly when combined with animal foods diet. Most of these are fairly uninteresting or unable to be binged upon. guava? papaya, pineapple? breadfruit? not exactly my cup of tea for 80% of my calories day in day out.
At least the modern fruitarians tend to combine some level of science? as they notice (probably correctly) that when you add a fair amount of fat (and animal protein always has SOME fat) that there are going to be even issues for a perfectly natural person - never mind a modern person with predisposition to all kinds of problems - doing so. I see no evidence currently that
raw fruit carb-based diets (animal food or not) can produce people that are healthy enough or have the strength and energy to actually stalk and hunt large prey at all. I have no interest in saying LC, VLC is superior to other diets only suggesting that the above 'diet' really has no record of success in existing modern or traditional peoples (heavy on lean heavy animal meats and tropical fruits). In traditional societies with perfect access to natural food we see either fat burning or a multitude of carb-based diets of cooked compact starchy foods even when fruits are everywhere.
http://world-food-and-wine.com/food-in-Africa I really have no problem with people promoting carb based diets as long as they realistically are meeting nutritional requirements and not saying eating 20 sweet modern fruits are better than some yams and vegetables because one is raw and the other cooked. These type of arguments clearly have no integrity or awareness to the realities of the past and the present.
On the other hand, obviously carb-based systems require and crave carbs. I don't think this makes any type of carb craving evil or unnatural as certainly vitamins and minerals are present in these foods, but if someone can't just eat a piece of fruit and then walk away, obviously there is some kind of fungal or addictive problem. Most people easily can skip to eat fat or protein if they are eating tons of sugar and I would suggest that entirely as a case for addiction rather than natural proclivity to carbs as energy. I can eat small amounts of all three if I had to, I'll just be hungry (eventually) as nature has twistedly only left us with those three things to choose to acquire fuel that all have supposed consequences. Most of this energy would have gone to acquiring
more food. The most efficient system of building energy (fats which then probably over time transitioned to complex carbs) wouldn't have so easily compensated for mediocrity in a natural setting.