You may have heard the research reported last week about fructose. In this study by Robert S Sherwin et. al. working at Yale and reported in the Journal of the American Medical Association, 20 healthy adults were given drinks sweetened with glucose or with fruit sugar (fructose). They then examined brain blood flow using magnetic resonance imaging (MRI).
The results of this experiment are best explained in their Yale press release.
They found that ingestion of glucose reduced cerebral blood flow and activity in brain regions that regulate appetite, but fructose did not. Ingestion of glucose also produced increased feelings of satisfaction and fullness, but fructose did not.
So, since a food or drink sweetened with fructose won’t “fill you up” you may end up eating more than you should.
Note, however, that this says almost nothing about high fructose corn syrup (HFCS) which is similar in content to table sugar, being about 55% fructose and 45% glucose. No experiments on HFCS were performed.
However, agave nectar, a popular “sugar substitute” is in fact around 90% fructose, depending on how it’s purified. If you think agave isn’t essentially sugar you’ve been misinformed. Agave syrup is pretty much fructose, and if the results of the Yale study hold up in larger studies, it in fact could be a cause of obesity. If you want to avoid the calories of sugars, you’d be better off with one of the artificial sweeteners, or perhaps stevia, although some find it has a bitter aftertaste.