Many experts claim that fructose may be the biggest culprit for obesity in the USA. This suggestion has been derived from four main observations:
- Many experiments with rats link fructose consumption to extraordinarily high levels of triglycerides as well as metabolic syndrome.
- In human trials, where subjects were fed with very high amounts of fructose, metabolic syndrome and obesity was observed to result from such a diet.
- The increase of fructose consumption over the past three decades is well correlated with the rise of obesity.
- Although fructose has not been seen to cause cancer, it promotes growth of already existing cancers.
Basically, these experiments conclude that if you have too much fructose in your diet, your triglyceride count will be higher and you will experience symptoms of metabolic syndrome. The question is how many people actually reach 200+ grams of fructose per day? Well, this interesting study found that most of us are underestimating the actual amounts of fructose in sweetened beverages, and manufacturers don’t disclose this information.
Is it the fructose or the excess calories?
Many of the experiments which show that fructose is bad fail to isolate it from excess calories. A review of previous studies concludes that in obese and overweight people, fructose has no causal effect on body weight or triglycerides, when consumed at normal levels.
Another review says that there is no link between moderate fructose intake (100 grams or less per day) and health risk markers and body weight.
This study shows that after completing a workout, fructose is much more effective at replenishing glycogen than glucose.
Here is a controlled experiment which studies fructose in an energy restricted diet. They compared a moderate fructose intake to a low fructose intake. What they learned was that weight was lost in both groups, but more weight was lost in the moderate fructose group, when the fructose came from natural sources like fruits. How can you lose weight with fructose in your diet, if it leads to higher triglycerides, obesity, and metabolic syndrome?
It would seem that pointing the finger at fructose is a scare tactic, nothing more. The reality appears to be that as long as you control your caloric intake, fructose is harmless. Excess calories lead to obesity, metabolic syndrome, and higher triglycerides regardless of the source of calories. However, in a caloric surplus, fructose will certainly cause more damage than other sugars.