Effect Of Dietary Fatty Acid Composition On Food Intake, Triglycerides, And Hypothalamic Peptides, Regulatory Peptides, January 2012
From the abstract:
"This study examined the effects of a high-fat diet containing relatively high levels of saturated compared to unsaturated fatty acids (HiSat) to a high-fat diet with higher levels of unsaturated fatty acids (USat).So,
A HiSat compared to USat meal caused rats to consume more calories in a subsequent chow test meal.
The HiSat meal also increased circulating levels of triglycerides (TG) and expression of the orexigenic peptides, galanin (GAL) ... and orexin (OX).
The importance of TG in producing these changes was supported by the finding that the TG-lowering medication gemfibrozil as compared to vehicle, when peripherally administered before consumption of a HiSat meal, significantly decreased the expression of OX.
These findings substantiate the importance of the fat composition in a diet, indicating that those rich in saturated compared to unsaturated fatty acids may promote overeating by increasing circulating lipids and specific hypothalamic peptides, GAL and OX, known to preferentially stimulate the consumption of a fat-rich diet."
Saturated Fat --> Higher Triglycerides --> Galanin and Orexin
Galanin and orexin both stimulate food intake, preferentially fat intake. Interestingly, it wasn't the saturated fat directly that caused the release of appetite stimulating chemicals, it was the high blood triglycerides.
What raises triglycerides besides saturated fat?
The Effect of Alcohol on Postprandial and Fasting Triglycerides, International Journal of Vascular Medicine, 2012
The body adapts to moderate and regular alcohol intake, 1 or 2 glasses a day. However, a dose more than usual spikes triglycerides. And:
"When alcohol consumption is accompanied by a meal containing fat, especially saturated fat, it has a significant additive effect on the postprandial triglyceride peak."Regarding that additive effect... In an earlier study, Leibowitz found that:
Alcohol --> Higher Triglycerides --> Galanin and Orexin --> Preference For Fat
Positive Relationship Between Dietary Fat, Ethanol Intake, Triglycerides, And Hypothalamic Peptides: Counteraction By Lipid-lowering Drugs, Alcohol, 2009
"These results support the existence of a vicious cycle between ethanol and fat, whereby each nutrient stimulates intake of the other. Within this vicious cycle, ethanol and fat act synergistically to increase TG levels, which in turn stimulate peptides that promote further consumption."This was interesting:
"Most importantly, ethanol and a high fat diet showed an interaction effect, whereby their combination produced a considerably larger increase in TG levels (+172%) compared to ethanol with a low fat diet (+111%)."So, eating more fat led to higher triglycerides.
Sugar and refined carbohydrates also raise triglycerides. Although, the mechanisms are more complex and beyond the scope of this post. Still, it's irresistible to imagine what might happen to triglycerides, and so to the impulse to overeat, if you added sugar to the fat&alcohol mix.