Does Your Diet Fail, 'cause You Sleep Too Little? 40 Minutes Extra Sleep Will Shed an Additional Pound of Fat in 6 Months

Image 1: Blindfolds are cheaper than light-tight curtains or shutters and they are more versatile ;-)

I have repeatedly emphasized the importance of quality sleep, here at the SuppVersity. Based on my own experience sleeping should be your your #1 priority if you want to look good, feel good and perform at your personal best on the cognitive and physiological level into your old age. Unfortunately, the number of controlled long(er)-term studies on the issue is quite small and the epidemiological data either unreliable, inconclusive or both (in most of the cases, the latter is the case; for a review see Nielsen. 2011). I was therefore happy to see that the results of one of the comparatively tightly controlled study from the Healthy Active Living and Obesity Research Group at the Children’s Hospital of Eastern Ontario Research Institute in Canada confirm my personal experience - even if the effect-size was not as pronounced as I would have expected. But let's take one thing after the other...

Take 123 overweight men and women and reduce their caloric intake by 600-700kcal ... 

... what is going to happen? Well, the answer to that question should be straight forward, right? These obese men and women, whose mean age was 41.1 years and who had an average BMI of 33.2kg/m², should begin losing weight, right? According to my previous post on "Busting the 3,500kcal = 1lbs Weight Loss Myth!" not necessarily 1lbs in 5-6 days but 1lbs in say 10 days should be the minimum. So, after the 24-week study period of trial Jean-Philippe Chaput and Angelo Tremblay conducted, the 90% of the participants who reported that they actually complied to the dietary prescription should be ~16.8lbs or 8.4kg lighter.

Figure 1: Lean mass and fat mass loss over the 24-week study period (left, calculated based on data + the information that the mean ratio of lean to fat mass loss was 3:10; Chaput. 2013); illustration of what min. and maximal weight loss would mean, if the data was normally distributed (right)

In view of the fallacy of the "calories-in-vs-calories-out" hypothesis and its logical consquence, the "eat less, lose more" diet trap, it should not come as a surprise that the average weight loss across all participants fell short of the expectations. In that, it is however interesting to remark that the expected 8.4kg are identical to the mean weight loss + one standard deviation of the same; now, if we assume a normal distribution (warning: scientific jargon! see figure 1, right for some illustrations ;-) of the data, this implies that ~16% of the subjects lost even more than my conservative prediction of 8.4kg would have suggested.

Never underestimate the fat-burning prowess of a good night's sleep!

The reasons the other 84% "underperformed", however, are manifold (keep in mind: Against the background that many obese people simply get more obese year by year even stagnation may have been progress for some). Those I consider the most important / likely ones are:

Table 1 (Chaput. 2013): This is the original table from the study and while it says "baseline characteristics" it is actually no wonder that the subjects did not lose more weight if their baseline energy intake was already as low as 1,310kcal (=5242kJ/day). After all, that would be what I would suggest as a good energy deficit (~20-30%) to lose weight, already.

• reporting to be compliant, when you actually are not - a 24h food recalls done every 2 weeks as in the study at hand are notoriously unreliable, even if subjects don't fake them intentionally.
• eating way too little - in view of the fact that the reported baseline calorie intake was only 1,310kcal the additional reduction of 600-700kcal put them in starvation mode; no wonder they hardly lost weight (I wonder if the authors did maybe enter the reduced energy intake into the "baseline characteristics table, accidentally; cf. table 1)
• not eating the right whole foods - people tend to think "if I go to starve I better starve on chocolate and pie than on broccoli and chicken filet", so that - in the absence of concrete meal plans - subjects would eat cream cake every day and still comply to their goal wrt to total energy intake

Non-compliance (suggested read: "High Carb vs. High Fat for Obese Type II Diabetics and What Really Happens, When Science Meets Real Life), over-dieting and food quality aside, there is a fourth factor which would have been on my list, as well, if it had not been on Chaput's and Tremblay's the research agend, anyways: SLEEP! Duration and quality.

Figure 2: Fat loss as a function of sleep duration (left) and sleep quality (middle; both based on Chaput. 2013); as well as the "normal" distribution of PSQI (sleep quality scores) among healthy people (right; from Buysse. 1998)

Interestingly enough, the total sleep duration remained a better predictor of dietary success, as defined by loss of pure body fat (r =0.26), than the actual sleep quality (r = -0.20; note: -1 or 1 would indicate perfect negative or perfect positive correlations) even after adjustment or age, sex, baseline BMI and the
change in total energy intake (r _Duration = 0.34 vs. r _Quality = -0.31; data not shown in figure 2). This may be surprising at first, but in view of the fact that only PSQI score greater than 5 are highly sensitive to determine whether you are or aren't a "good sleeper" it appears reasonable.

And still, my personal experience tells me that without a reasonably good sleep quality you will rather feel worse than better if you simply stayed in bed for another 83min. So my suggestion remains (see implications for more): Get yourself a blindfold and earplugs - it will make a huge change to your sleep quality and you ability to sleep longer and wake up more refreshed and don't worry about either the alarm clock or your partner. While you will hear the former anyway, your partner certainly won't mind if you are better rested and physically more attractive than ever, although that may mean that he or she will be nudging you more often to put the blindfolds to an alternative and certainly not less enjoyable use ;-)

Implications: The results of this study put another emphasis on the importance of good sleep (7-9h every night) in the context of losing weight, building a better physique and living an overall healthier and happier life. Aside from the previously mentioned ear-plugs and blindfolds, there are yet a couple of other things you can / should do to get the sleep your body needs

• go to bed with or as closely after sundown, whenever this is possible - don't worry if you are "up early" this is how life is supposed to be, not the other way around (note: alarm clocks are 100% non-paleo ;-)
• don't sacrifice your social life for sleep, but don't persuade yourself that you have to party everyday and thus cannot go to bed in time
• don't use your computer / mobile phone / social media in the vicinity of going to bed; it will delay your ability to fall asleep and the light of the small (often blueish) LCD screens will interfere with your circadian rhythm
• if anything have a shake or other readily digestible food before bed, otherwise digestion may interfere with  your sleep quality in the first 2h and losing 2 out of 8 hours of sleep could already cost you 1.4kg of body fat you would otherwise have lost (you know the figure is mere statistical shenanigan, right?)
• plan your TV consumption and set a deadline for when the boob tube must be off; even consider buying a timer switch to make sure it will be off
• consider using melatonin and light therapy for a short period of time (or strategically, when you are a shift worker) to get into the new rhythm (dosing 3-10 mg melatonin before bed, 15-45min bright light therapy when you wake up or strategically during night shifts; eg. Sharkey. 2001; Bjorvatn. 2007; Sadeghniiat-Haghighi. 2008)

There will be way more on this in the future, as I am - as some of the SuppVersity Facebook friends know - still working on a post / series of posts on the circadian rhythm and a couple of past experiences of my own - including the use of light therapy to tweak my biorhythm. For the time being I suggest that you go to the official PSQI website, download the test (click on "PSQI instrument"), fill out and evaluate the questionnaire, take the first 5 steps I have outlined above, and see if that's not already enough to get an even better night's sleep in the next two weeks to come. And just in case that's not enough or your partner has gotten so fond of the blindfolds that there simply is too little time left for sleeping during the night hours, you will soon find more information on the 6th bullet point and the whole theoretical background of circadian rhythmicity and how it can work for, but also against your... until then, good night!

References:

• Bjorvatn B, Stangenes K, Oyane N, Forberg K, Lowden A, Holsten F, Akerstedt T. Randomized placebo-controlled field study of the effects of bright light and melatonin in adaptation to night work. Scand J Work Environ Health. 2007 Jun;33(3):204-14. 
• Buysse DJ, Reynolds CF 3rd, Monk TH, Berman SR, Kupfer DJ. The Pittsburgh Sleep Quality Index: a new instrument for psychiatric practice and research. Psychiatry Res. 1989 May;28(2):193-213.
• Chaput JP, Tremblay A. Sleeping Habits Predict the Magnitude of Fat Loss in Adults Exposed to Moderate Caloric Restriction. Obes Facts 2013;5:561–566.
• Nielsen LS, Danielsen KV, Sørensen TI: Short sleep duration as a possible cause of obesity: critical analysis of the epidemiological evidence. Obes Rev 2011; 12: 78–92.
• Sadeghniiat-Haghighi K, Aminian O, Pouryaghoub G, Yazdi Z. Efficacy and hypnotic effects of melatonin in shift-work nurses: double-blind, placebo-controlled crossover trial. J Circadian Rhythms. 2008 Oct 29;6:10.
• Sharkey KM, Fogg LF, Eastman CI. Effects of melatonin administration on daytime sleep after simulated night shift work. J Sleep Res. 2001 Sep;10(3):181-92.

90 Min Sleep Restriction - How Bad is It Really? Changes in Insulin Resistance Last For One Week - Until the System Adapts. Plus: Subjects Even Reduce Weight & Waistline

In general it's certainly a good idea to rise, when the cock crows on the dung heap, but what if that means you miss 90 min of your precious sleep?

"Tell me how and how long you slept last night and I'll tell you something about your chances of getting / staying lean and healthy!" It sounds more straight forward than the stupid AM vs. PM system you, my American friends, are still sticking to: If you consistently miss just one hour of sleep, you are messing with your insulin sensitivity, body weight and your plasma concentrations of leptin. But is this actually accurate and "how much messing" does it actually take? A close analysis of a recent study by a group of researchers from University of Surrey in Guildford, UK (Robertson. 2013), does at least raise some questions in how far smaller deviations from your usual 24/7 x 365 consistency will mess with your physique and health.

Can you "wake your way" towards obesity?

"Mild sleep restriction" is what scientists call it, when you miss 'only' one hour of your regular 7-8h of sleep every night and "mild sleep restriction" is also what the 19 healthy young normalweight men in the Robertson study have been exposed to over a three-week period.

Just in case you have forgotten about it, you can do the Munich Chronotype test for free (including personal evaluation) right at the website of the University of Munich (click here to be redirected)

Healthy male students, aged 20–30years, BMI 19–26kg/m² were recruited for this randomized–controlled sleep intervention study [...] those with a self-reported sleep length of 7.0–7.5h were invited for more detailed screening.[...] According to self-report, volunteers were not taking prescription or over the counter medication and had a stable weight for >3months. Specific exclusion criteria also included (i) shift-work and travel beyond 2 time zones in the preceding 2months, (ii) high intake of caffeine and alcohol, (iii) extreme morning or evening preference assessed with the Munich Chronotype and Horne Östberg Questionnaire, (iv) a self-reported sleep problem (Pittsburgh Sleep Quality Index global score≥6) and (v) daytime naps in the preceding 4weeks.

Before the actual study began, the habitual sleep patterns were assessed by actigraphy and sleep diary information collected during a two week baseline period. The subjects were then  randomized to either the

• restricted group spending their regular time-in-bed minus 1.5h per night, or the
• habitual group who simply followed their habitual sleeping patterns

The participants had to fill out sleep logs in order to assure compliance. Moreover, participants were instructed not to take naps during the day . The actual acquisition of the weight, blood pressure and adiposity data, as well as the leptin and adiponectin levels, and information about  arterial stiffness took place after a 12h overnight fast, at the Centre for Endocrinology Diabetes and Research (the oral glucose tolerance used to evaluate the effects of sleep deprivation on insulin sensitivity took place at the CEDAR, as well). The procedure was conducted four times, initially following the 2-week baseline period and in weekly intervals for the 3 weeks of the intervention, thereafter.

Figure 1: Relative changes of insulin sensitivity (HOMA-IR), fasting blood glucose and adiponectin levels in the course of the three-week study period (Robertson. 2013)

If you simply went by the absolute data and the short but concise summary of the main results the researchers provide in the abstract it would in fact seem as if the provocative statement I at the very beginning of this article would be spot on and you would add a pound of fat to your frame and lose a full week of your precious life-time with each minute of sleep you are missing. If you put things into perspective by calculating the relative changes, you cannot but realize that sleeping 90min less may not be ideal, but it's "medium term"  effects are probably overrated.

Figure 2: Illustrated and annotated version of the graph depicting the change in insulin sensitivity in the habitual (open circles) and sleep restricted (closed circles) group (Robertson. 2013)

In fact, the plot of the changes in insulin sensitivity in figure 2 clearly suggests that there is something like an adaptation process that compensates for the initial reduction in insulin sensitivity once a new 'sleep steady state' is achieved. In the absence of data from the following weeks, we cannot however exclude that the in an even longer-term scenario the reduction of sleep duration from below the 5h mark would not have had a negative impact on the overall and metabolic health of the subjects. In this context, Robertson et al. point out that

"[...] some of the effects of sleep restriction appear transient, i.e. we have beenunable to confirm a change in insulin sensitivity beyond one week of sleep restriction [and that t]he data clearly indicate that the effects of a reduction in sleep duration may change in the course of the exposure to sleep reduction, [which renders any] extrapolation from single visit laboratory studies to epidemiological data problematic." (Roberston. 2013)

If we would yet discard the epidemiological findings and simply ignore the constant increase in fasting blood glucose and rely on the fact that the insulin tolerance returned to baseline after an initial drop, we could even (ab-)use the data from the study at hand to argue in favor of sleep "deprivation" (I am deliberately using quotation marks, because the previously mentioned adapation process would suggest that the subjects were not actually "deprived") as a means to reduce the obesity epidemic. After all the subjects in the sleep restricted group did lose some body weight and reduced their adiposity index, the waist equivalent to the BMI (higher values = higher ratio of waist to body height), by meager, but at least measurable 0.8%.

Believe me: Fridge raiding is your least problem if you don't sleep at night. If you want to know more about the profound metabolic, psychological and even carcinogenic effects of having or not having a regular sleeping rhythm, why a dark room is important and more, read up on the Circadian Rhythm Series

Sleep does not necessary equal sleep: It should also be mentioned that "sleep" data we are talking about is actually data spent in bed and if you take a look at the sleep latency, you will realize that the subjects in the restricted group made up for 4-8 minutes of their 90min sleep debt by simply falling asleep more readily. Another factor to keep in mind is that, at least in my humble opinion, the actual sleep duration of the young men who participated in the study was to low to begin with. This is just my personal N=1 experience, but whenever the demands of life (or my own stupidity) forced me onto a <7h sleeping schedule, I ended up gaining body fat - not necessarily weight, but fat. So if there is something like a "break even" and the subjects were below that already, the effects could be much more pronounced in someone like you, who is (hopefully) getting is 7h of sleep in a pitch black, quiet room every night.

And what's more, in the correlation analysis the scientists conducted, the only parameter with a statistically singnificant correlation with sleep duration was - you won't guess that - body weight! With a positive correlation of +0.271 indicating that shorter sleep durations exhibited - at least in the study at hand - statistically significant correlations with decreases in body weight.

So what? You cannot 'wake yourself lean', can you?

No, probably not. The evidence from epidemiological studies is too overwhelming to throw the insufficient sleep = diabesity hypothesis over board. On the other hand, the results of the study at hand are interesting, as they clearly suggest that (a) our bodies are able to adapt to a news steady state within a certain window of suboptimal to optimal sleeping time and (b) that the short term effects of what I would like to identify as an actue stressor, namely 1-2 weeks of reduced sleep will lead to similarly transient weight loss.

Previous study showed: When you are dieting 40min extra sleep can help you 1lbs extra fat (read more).

increases in cortisol levels do the exact same thing. In the short run, they will spike you up (Lance Armstrong has admitted using corticosteroids to outperform the competition only days ago). Used intermediately, they will begin to gnaw on your body fat and muscles and in the long run they will totally mess up your metabolism (this assumes chronic low level exposure). To cut a long story short: The study at hand clearly suggests that someone without pre-existing health problems, a young man or woman in the prime of your life, won't risk becoming diabetic during the exam preparations or during any other period in his / her life, where he / she has to reduce the habitual and natural sleep durations by 90min for a <1 month in order to cope with external circumstances he or she has no bearing on.

Bottom line: Now, does this mean that we have been overrating the importance of sleep hygiene before? Certainly not. What we may have underestimated, however, are short-term compensatory effects which allow for a brief, but non-negligible time window, in which neither the acute very short-term effects - nor the chronic (very) long-term effects of sleep deprivation will harm you. And though we don't know anything about the size of this window, one thing appears to be certain: It's large enough for exam preparations, but not for years of drinking, partying and doing all sorts of things but sleeping ;-)

References

• Robertson MD, Russell-Jones D, Umpleby AM, Dijk DJ. Effects of three weeks of mild sleep restriction implemented in the home environment on multiple metabolic and endocrine markers in healthy young men. Metabolism. 2013 Sep 15.