When searching the internet, it is not particularly difficult to find arguments either saying that fructose is the devil or that fructose is the victim of a terrible misunderstanding.
Which is it then?
From everything I have seen and heard, all the research I have seen and done (admittedly, I am no scientist, so bear that in mind as I proceed through this), fructose is to blame for the rapid and worrying increase in obesity… but not alone. It is not be the sole contributing factor, but it definitely is one of the bigger ones (no pun intended).
Where to start then?
Starting with fructose, the sweet tasting compound found in fruits, honey, etc, and the primary contributing sweetness agent in nearly anything that has a sweet taste these days. To not say that fructose is “poison that should be avoided at all costs”, smaller amounts of it should not hurt. Timing will also be an issue, as the body can use fructose to restore glycogen stores after a workout, even if glucose serves this purpose better. Outside of this, however, fructose – consumed alongside glucose, since this is how it is found both in nature and in artificial sugars – gets metabolized into fat by the liver. It has been found that the higher the glucose:fructose ratio, the less this occurs, but it does not eliminate the effect. Fructose is even suggested to be the leading contributor of metabolic syndrome and weight gain, among other things.
As if that was not bad enough, sugar in general has been shown to have some other nefarious effects, which should be enough to not want to eat it.
Ok, so fructose is pretty bad to have all over our diet, that much seems to be clear, and it should certainly be minimized in our diet. But to call it the only issue is quite an overstatement.
After all, there is the issue of fat to consider. And not just any fat either… in particular, trans-fats. No, not cholesterol or even saturated fat, just trans-fat, the stuff you may also read on a label as “[partially] hydrogenated [some kind of] oil”. In an interview with Dr. Kummerow, who pretty much started the research on trans-fat in the first place, it is explained that it has a massive negative impact on health – most of which is commonly associated today with cholesterol and saturated fat. It is worth noting in this that a good portion of our saturated fat intake comes from hydrogenated oils, which means that there is trans-fat contained in it as well, making it difficult to differentiate between the effects of the two; no research that I’ve found has taken the time to differentiate between fully hydrogenated oils, natural saturated non-animal fat (e.g. coconut oil), or animal fat (and what those animals would have been fed).
However, since unsaturated fats (where there are one or more double bonds) break down into trans-fats when cooking, even at relatively low temperatures, and do so from their double bonds, natural saturated fat is something that can prevent trans-fats from appearing in your food. To know whether fat is primarily saturated or unsaturated, it is fairly simple: does it stay solid at room temperature? If so, you are using a mainly saturated fat. Examples include butter, coconut oil, and most animal fat.
I am not suggesting to eat lard by the spoon-full here. Unsaturated fats – in particular, oils rich in monounsaturated fat (small breakdown of some of the better ones, and some claimed to be better that really are not) – have been shown to reduce the risk of heart disease in a statistically significant way… meaning enjoy that olive oil on your Greek salad, it’s good for you! As mentioned in the paragraph above, however, please avoid it when cooking, since the unsaturated fats tend to breakdown as you cook at higher temperatures, and you do not want that!
One more thing before concluding: I have heard it claimed that a “Paleo diet will kill you” or, more relevantly, a Paleo diet removes starches and vegetables from one’s diet. While this is not an article specifically about Paleo or fighting this video’s talk, it is worth at least noting that starch – in reasonable (read: small) quantities – and vegetables by the bucket-load is something that should definitely be an important part of everyone’s diet.
Are there other causes to obesity in our diets? Most likely… the widespread use of chemicals in our food is probably not helping, and then there’s the sheer size of the portions often being eaten on a regular basis. Additionally, this is a very simplified article, and while I recommend doing more research on the matter, you’ll find that there is a lot of conflicting data out there; the idea is simply to give you an idea of which direction to approach from. But if anything, hopefully you’ll feel better about your breakfast of eggs, [uncured] bacon, and potatoes after reading this!