Here’s an interesting study on High Fat diets and Time Restricted Feeding (Sherman H1, Genzer Y, Cohen R, Chapnik N, Madar Z, Froy O. Timed high-fat diet resets circadian metabolism and prevents obesity. FASEB J. 2012 Aug;26(8):3493-502. doi: 10.1096/fj.12-208868. Epub 2012 May 16.). The study
…tested whether long-term (18 wk) clock resetting by RF can attenuate the disruptive effects of diet-induced obesity.
The study looked at:
Analyses included liver clock gene expression, locomotor activity, blood glucose, metabolic markers, lipids, and hormones around the circadian cycle for a more accurate assessment.
Geneticaly, the study claims that:
Compared with mice fed the HF diet ad libitum, the timed HF diet restored the expression phase of the clock genes Clock and Cry1 and phase-advanced Per1, Per2, Cry2, Bmal1, Rorα, and Rev-erbα.
As far as weight goes:
Although timed HF-diet-fed mice consumed the same amount of calories as ad libitum low-fat diet-fed mice, they showed 12% reduced body weight, 21% reduced cholesterol levels, and 1.4-fold increased insulin sensitivity.
So, against a low fat diet the high fat diet did well. So far nothing new from usual. But what the study was concerned with was the Time Restricted Feeding (Intermittent Fasting) aspect. And that’s where the TRF diet did very well.
Compared with the HF diet ad libitum, the timed HF diet led to 18% lower body weight, 30% decreased cholesterol levels, 10% reduced TNF-α levels, and 3.7-fold improved insulin sensitivity. Timed HF-diet-fed mice exhibited a better satiated and less stressed phenotype of 25% lower ghrelin and 53% lower corticosterone levels compared with mice fed the timed low-fat diet. Taken together, our findings suggest that timing can prevent obesity and rectify the harmful effects of a HF diet.
Here’s a related paper which notes a second study (Timed High Fat Diet Resets Circadian Metabolism and Prevents Obesity).
By an odd coincidence, a similar paper was published in the FASEB J2 about a month later, but the second paper didn’t seem to be aware of the first paper’s publication and didn’t cite it. In fact, the authors of the second paper thought that their paper was the first to be published on the subject of time restricted feeding of a high fat diet.
Here’s the second paper (Hatori M, Vollmers C, Zarrinpar A, DiTacchio L, Bushong EA, Gill S, Leblanc M, Chaix A, Joens M, Fitzpatrick JA, Ellisman MH, Panda S. Time-restricted feeding without reducing caloric intake prevents metabolic diseases in mice fed a high-fat diet. Cell Metab. 2012 Jun 6;15(6):848-60). Here’s that abstract:
While diet-induced obesity has been exclusively attributed to increased caloric intake from fat, animals fed a high-fat diet (HFD) ad libitum (ad lib) eat frequently throughout day and night, disrupting the normal feeding cycle. To test whether obesity and metabolic diseases result from HFD or disruption of metabolic cycles, we subjected mice to either ad lib or time-restricted feeding (tRF) of a HFD for 8 hr per day. Mice under tRF consume equivalent calories from HFD as those with ad lib access yet are protected against obesity, hyperinsulinemia, hepatic steatosis, and inflammation and have improved motor coordination. The tRF regimen improved CREB, mTOR, and AMPK pathway function and oscillations of the circadian clock and their target genes’ expression. These changes in catabolic and anabolic pathways altered liver metabolome and improved nutrient utilization and energy expenditure. We demonstrate in mice that tRF regimen is a nonpharmacological strategy against obesity and associated diseases.
I was pointed to this by an article by Mark Hyman who claimed about the study that:
Note that the link is not to a human study but to the mouse study above. A tale of mice or men. Someone in a Facebook group pointed me to the study as proof that we can eat fat ad lib. LOL. Proves exactly the opposite.