Blog › Forums › Nutrition › Saturated and Simple Sugars Cause Hypothalmus Damage and Obesity? › Reply To: Saturated and Simple Sugars Cause Hypothalmus Damage and Obesity?
I wanted to share a few thoughts on this study and others like it.
Here is a link to the whole article for those who have access (I do; in fact, I would attach the whole article if this forum could allow attachments, hint hint!)
Stephan Guyenet posted something similar coming out of his lab a while ago:
My overview of the articles is that fructose and sucrose, in rats and in concentrations over 20% of the diet, stimulate a variety of inflammatory mediators that leads to liver damage and hypothalamic damage which can result in long-term set point dysregulations. According to the papers, glucose at any concentrations does not do this. From my reading, these manifestations are consistent with endotoxemia (mild ‘sepsis’) that result from fructose being malabsorbed and fermented into junk by gut bacteria/fungus/whatever.
Antibiotics given with the fructose prevents the liver injury.
In healthy humans, fructose is completely absorbed without problematic fermentation PROVIDED THAT the fructose is ingested CONCOMITANTLY WITH equal amounts of glucose. Glucose somehow facilitates the speedy absorption of fructose. In humans, sucrose (50:50 glucose:fructose) up to 100 grams or so in one sitting appear to be fine.
Again, though, this was in ‘healthy humans’. This is consistent with the rat studies that show up to 10% sucrose is ok (5% fructose) and does not lead to any problems. Considering that most of these studies used 60% fat diets, this would mean about > 3:1 ratio of glucose:fructose. Thus, fruit and honey and natural things that contain roughly equal parts fructose and glucose would be fine for most healthy people, while particularly unhealthy people may want to have even more glucose and less fructose.
Dietary ‘Saturated Fat’:
After reading the papers over very carefully, I see ZERO discussion of ‘saturated fat’ outside of the conclusion, and all the trials were given up to 60% TOTAL FAT. The studies are showing that 60% fat diets can injure the brain and lead to obesity and diabetes compared to ‘control’ diets that are low fat and low fructose (high starch). Separate studies (summarized within the same papers) show that high fat diets (or medium fat diets) that are supplemented with EPA and DHA from fish oil (so, high Omega-3 PUFA, NOT omega-6 PUFA or miscellaneous PUFA) increase neurogenesis and thereby partially correct for the brain destruction from the high fat and/or high fructose diets.
These conclusions in the paper are appalling to me since they didn’t take into account the fact that the base composition of the fat (whether ‘High Fat’ or otherwise) are predominantly high PUFA lard and high PUFA vege oils.
As Masterjohn wrote a while back, the specific ‘High Fat’ diet used in most of these injurious diets was >30% PUFA (>50% of the fat was PUFA), with almost all the PUFA coming from linoleic acid (18:2, omega 6; the same major fatty acid as in soybean or corn oil).
Masterjohn has actually eloquently written about this many times before, including in his article ‘Good Lard, Bad Lard’, but the site is down for me at the moment.
This diet is often referred to as ‘High Saturated Fat’, but this is another example of researchers just flat-out lying to make a headline.
So, back to the hypothalamic injury: we see that high fat diets WHEN THEY ARE HIGH IN LINOLEIC ACID, destroy the brain (and many other things), but decreasing this and adding fish oil somewhat counters this effect. All this proves is that omega 3 deficiency destroys the brain, and that high linoeic acid diets lead to omega 3 deficiency.
IN SUMMARY, what is being claimed is that high sugar and high fat/saturated fat diets are injurious. In reality, the data actually shows that high fructose/sucrose and/or high vege oil diets are injurious. The vege oil thing we already knew. The fructose/sucrose thing I think is, AT THIS TIME, equivocal, but LIKELY IN MY ESTIMATE attributable to fructose malabsorption, which is a problem of fructose in excess of glucose–something much more likely with synthetic sweeteners and less likely with fruit, honey, and even cane sugar.