|Sleep is a constantly underestimated factor in getting and staying lean. Don't be fooled by statistics.|
If we put some faith into the results of a recent study from the Department of Gastroenterology and Metabology at the Ehime University Graduate School of Medicine in Japan (Miyake. 2014), you just have to follow three simple rules: Don't snack, get 7+ hours of sleep and by God, don't sit around all day!
I know that this is not revolutionary new. If you look around, though, most people still believe in the all or nothing approach that's doomed to failure for 99% of the people.
Instead of eating only chicken, broccoli and rice or, even worse and totally en vogue these days, eggs, bacon and ... well, eggs and bacon, of course, a first and, according to the results Teruki Meyake and colleagues present in the latest issue of the Journal of Gastroenterology very promising first step would be to stop snacking (learn more about snacking).
|Figure 1: Association between the habit of snacking and prevalence of NAFLD by sex; the asterisks indicate statistical significance with * p < 0.05, ** p = 0.002 (Miyake. 2014)|
Ladies, you better have a big steak for lunch and skip the cupcake in the afternoon!
What's interesting, though is that the statistical significance* of the difference between no-snackers and snackers is particularly pronounced in women and that in spite of an overall lower prevalence of NAFLD + snacking in the fairer sex (see Figure 1, right).
Apropos sex-differences, if you look at the effects of bad sleep habits you will realize that the visible differences between the number of NAFLD cases among the short (and insufficient) and the long (and sufficient) sleepers is significant only for the women among the 11,094 Japanese subjects.
|Figure 2: Association between the habit of sleep duration (in h) and prevalence of NAFLD by sex; the asterisks indicate statistical significance with * p < 0.05, ** p = 0.002 (Miyake. 2014)|
|The participants of a 10,000 steps a day challenge / study by scientists from Arizona State University lost 3 cm off his / her waist - in spite of a hilariously low overall adherence (Walker. 2014)|
Both will work only, if the one and only independent predictor of non-alcoholic liver disease is in place: Exercise... well, or at least regular physical activity that goes beyond walking from the sofa to your snack cabinet to grab another candy bar.
In their latest study, Myiake et al. report an almost linear relation between the rate of physical activity on the one hand, and the prevalence of non-alcoholic fatty liver disease, on the other hand.
This relationship holds in men and pre-menopausal women. Among the post-menopausal women, on the other hand, periodical exercise alone (probably misreported, anyways ;-) was not associated with a reduced NAFLD prevalence compared to women who did not exercise at all.
Don't give up on exercise, Ladies! Needless to say that the lack of an association of regular physical activity with reduced NAFLD risk is a result that stands in stark contrast with dozens of controlled experimental trials. If anyone benefits from exercise, specifically resistance training, it's women in their best (post-menopausal) years. So, ladies, don't even think about decreasing your physical activity and trying to achieve optimal health by starving yourselves or surgery!It's also worth mentioning that I underlined the word "independent" in a previous paragraph for a purpose.It is after all easy to find a statistical significant association between two parameters (in this case short sleep duration ⇆ NAFLD and snacking ⇆ NAFLD).
|Figure 3: Unadjusted and adjusted* increase in NAFLD risk for snacking, no exercise, and short sleep duration; *adjusted for see paragraph below (Miyake. 2014)|
- Johnsen, May Trude, Rolf Wynn, and Trond Bratlid. "Optimal Sleep Duration in the Subarctic with Respect to Obesity Risk Is 8–9 Hours." PloS one 8.2 (2013): e56756.
- Miyake, Teruki, et al. "Significance of exercise in nonalcoholic fatty liver disease in men: a community-based large cross-sectional study." Journal of Gastroenterology (2014): 1-8.
- Walker, Jenelle R., et al. "US Cohort Differences in Body Composition Outcomes of a 6-Month Pedometer-Based Physical Activity Intervention: The ASUKI Step Study." Asian Journal of Sports Medicine (2014).