Saturday, May 23, 2015

So, "Intermittent Fasting Does Now Make You Fat"? Do the Facebook Posts Lie? Not Necessarily, but Many People Confuse the Important With the Irrelevant Information

It were the nightly binges, not the fasting that made the rodents fat... and it's not news that starving and bingeing is obesogenic, is it?
Recently, Kara L. Kliewer and her colleagues, probably tried to do something good, when they conducted a study to "capture intraday oscillations in lipid stores and adipose tissue gene expression in gorging mice and to identify metabolic consequences of gorging precipitated by food restriction during weight regain" (Kliewer. 2015). Whether what came out of it, i.e. articles saying that "Skipping Meals Promotes Belly Fat Storage, Increases Risk For Insulin Resistance" (MedicalDaily), however, will help people avoid help you lose body or belly fat appears to be highly questionable, though. After all, the mainstream interpretation of the study is rigid with respect to its implications.
Do you have to worry about fasting when your're dieting!?

Breakfast and Circadian Rhythm

Does Meal Timing Matter?

Habits Determine Effects of Fasting

Breaking the Fast & the Brain

Does the Break- Fast-Myth Break?

Breakfast? (Un?) Biased Review
Before we delve further into the details, however, let's briefly take a look at what the researchers from the Ohio State University actually did: As you can see in Figure 1 we are - and this is by no means clear whence you're reading only the press-release "copy-and-paste"-jobs online - actually dealing with a feeding regimen that looks pretty similar to what people usually think of when they are talking about intermittent fasting.
Figure 1: Feeding and fasting cycles and metabolic states in 24h feeding cycle (Kliewer. 2015).
So, basically, we are talking about a ~15h fast with that is followed by a 7h feeding window. But there are significant differences to intermittent fasting in humans:
  1. Gorging is not allowed on IF-regimen - Usually people who follow intermittent fasting regimens are somewhat anal about their nutrition. A binge like the one that occurred in the mice during the feeding phase is therefore representative mostly of the obese who don't "fast" in the sense of "intermittent fasting", but try to starve themselves for 24h failing only to fall victim to their own cravings late at night (remember: mice are active at night, so their biological clock is inverted compare to ours).
  2. Feeding does not occur at the wrong time on IF-regimen - Since we are already talking about "falling victim to [one's] cravings late at night," someone doing a real IF-regimen would never feed at night. He would do it in the early to late afternoon to avoid messing with his cicrcadian rhythm. The mice in the study at hand, however, were fat one-third into the "light period", which is their night and according to the rodents' biological clock not a proper time to "gorge".
Against that background I would be more than hesitant to use the study at hand as evidence of the adipogenic effects of intermittent fasting.
Figure 2: Yes, there's an increase in body weight (albeit not to the same weight as in the control group) and there is an increase in body fat, but both are due to "binging" not due to fasting (Kliewer. 2015).
Rather than that, you will probably see increases in visceral body fat as they are shown in Figure 2 (right hand side) in the previously mentioned "failed self-starvers" who starve all-day and gorge at night - none of my previous intermittent fasting suggestions involved either of these practices (i.e. starving and gorging).
Your breakfast habits determine what happens if you skip it | more.
Does breakfast skipping make you fat? If you've read my previous analysis of studies on skipping breakfast you should know that the overgeneralizing conclusion that is inherent in the previous question is undue and ignorant of the fact that this depends on the inability to stick to ones diet and the thus individual effects of breakfast skipping on the 24h energy balance which can and will differ from one individual to the next.
And if we put faith into the latest study from the University of Colorado School of Medicine and the Denver Health Medical Center it is your breakfast-eating or -skipping habit that determines the effects of breakfast skipping.
I am thus pretty sure that you have not ruined your body composition if you've been skipping breakfast or even breakfast and launch recently; and that's even more true, if you have followed my advice to use intermittent fasting as a short-term program to lose fat by combining timing and energetic restriction to your advantage.

If you have don just that, you don't have to care about the idiots who are still trying to propagate the myth of "frequent meals for fat loss". If they (a) knew the difference between intermittent fasting and starving and (b) had not relied on an already messed up press release, but had read the study, they would have been aware that  the researchers themselves state that the mechanism for the increased fat gains still has to be elucidated:
"Future studies should determine whether changes in adipose tissue gene expressions, lipid stores, and whole-body metabolism in our study can be attributed to the initial food restriction, circadian disturbances, and/or gorging eating pattern" (Kliewer. 2015).
And let's be honest, do you really think it's the meal skipping, not gorging at a (internal clock-wise) totally wrong time that made the mice fat? If so, you have probably been exposed to too much "frequent meal propaganda" in the past years.
This is not the first study to show that post-fasting binges are obesogenic (in rodents): "Every-Other-Day-Fasting Doubles Visceral Fat in 3 Weeks - Despite 60% Reduced Energy Intakes, At Least in Young Mice" - so, if you want to fast, do it while you are in a caloric deficit. That's the foundation on which the beneficial body composition effects depend | read more
So what, does (intermittent) fasting make you fat? It is quite easy to answer this question, because it is quite obvious that neither the rodents in the study at hand, nor any man will ever have become fat while fasting. Rather than that it's an uncontrolled binge after an extended "starving" (not fasting) window that will promote the storage of body fat.

And actually, that's the reason why I did never recommend the use of intermittent feeding protocols on ad-libitum or weight gain diets. If you are strictly controlling your food intake, just like you'd do it, when you're trying to shed body fat, though, there is no conclusive evidence (neither from this nor any other study) that the use of sensible intermittent fasting regimen that won't have you binge at times when you're supposed to sleep would impair your fat loss, let alone trigger fat gain | Comment on Facebook!
  • Kliewer, Kara L., et al. "Short-term food restriction followed by controlled refeeding promotes gorging behavior, enhances fat deposition, and diminishes insulin sensitivity in mice." The Journal of nutritional biochemistry (2015).