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. 2012); 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. 2012): 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. 2012); 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 2012;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.

NSSRT for NAFLD - No Snacks, Adequate Sleep & Regular Training | Plus: 3+1 Step Program to Helps Friends & Family Making Progress Towards a Healthier Lifestyle

Sleep is a constantly underestimated factor in getting and staying lean. Don't be fooled by statistics.

As a SuppVersity reader you know about the role of compromised liver health in the etiology of the diabesity epidemic: When the liver is clogged up with fat, your blood glucose and lipid levels will go overboard. Against that background it is all the more important to know that it's not overtly difficult to prevent that from happening.

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!

You can learn more about snacking & co at the SuppVersity

Fridge Raiders? Night Time Snacking

Protein Snack Shifts Macro Ratio for the Better

High Meal Frequency, High Body Fat

Alternate Fasting: Eating only a snack

Snacking Increases Obesity Risk

High or Low Protein? Casein or Whey?

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)

In fact, a brief glance at the prevalence of NAFLD in men and women in Figure 1 should suffice to tell you: Snacking and not giving your liver and the rest of your organs a "clean up the mess and ramp up the fatty acid oxidation" timeout from time to time is about the worst thing you can do for your liver.

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).

*What is statistical significance? Usually we simply speak of "p", the probability that a certain observation, in the study at hand, the difference in NAFLD rates between snacker and non-snackers, is just coincidence. In that, at value of p = 0.05 or in words, a probability of 5% that the observation is mere coincidence is considered "statistically significant" - everything else is "non-significant" and usually discarded as mere chance.

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)

For the men, on the other hand, there is only a non-significant trend towards reduced NAFLD rates with longer sleep. Moreover, unlike for women, for men sleeping more than 8h does not offer an advantage.

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)

Now the latter is actually something I would have expected for the female subjects as well, because most of the studies that investigate optimal sleeping pattern estimate the "optimal sleep duration" to be ~7-8h and not in the 9h+ zone. Things may differ, though, for people living above the Arctic Circle. People such as the 6413 persons aged between 30–65 years who participated in the Tromsø Study and for whom the optimal sleep duration for obesity protection appears to be 8–9 hours, i.e. one hour longer than for folks who live in parts of the world with longer days and shorter nights (Johnsen. 2013). In the end, sleeping enough and not snacking alone is not enough to escape the pro-obesogenic steatosis of your liver, anyway. 

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)

It is yet rare and a much better indicator of a causal relationship to find a statistically relationship between two parameters like physical activity ⇆ NAFLD (see Figure 3), that remains statistically significant after being controlled for age, BMI, high blood pressure, triglycerides, HDL-c, fasting blood sugar, uric acid, ALT (liver health), creatinine (kidney health), snacking and sleep duration. The latter, i.e. an independent association between a given lifestyle parameter and the prevalence of NAFLD was observed only for physical activity.

This is how you start a family member out: If you know someone (men or women, this works for both) you want to help overcome his unhealthy lifestyle, this is how you do it:

(1) No snacking: Have him eat three square meals. No snacks or caloric beverages (coffee or tea with milk and sweeteners are allowed) in between.

(2) 7-8h of sleep: Make sure that he gets 7-8h of sleep regularly. That means that the occasional day with less sleep is allowed. What's important and often overlooked, though, is that the rhythm must remain intact. It's thus better to get only 5h of sleep once and maintain your regular wake up routine and time, e.g. 7am, than sleeping 7-8h everyday, but from 10pm to 6pm on day one, from 2am to 10am on day to and so on.

(3) Walking + body weight workouts: Buy a pedometer and tell him about the 3 cm reduction in waist circumference the participants of the ASUKI study lost over 6 months. Start him out on a 5,000 step minimum in the first month tell him to increase the volume by 1,000 steps every other week until he is walking 10,000 steps a day. Make it clear that additional 3x body-weight workouts (details on the left), will ensure that there are visible changes in the mirror (not necessarily on the scale!) after only one month.

(*) No processed foods + 30g protein per meal: While it is obligatory to remind him constantly that it is necessary to minimize the amount of processed food in his diet don't overwhelm him by having him stop "cold turkey". Start with one "zero processed food" meal every other day and 10g protein per meal and have him  build from there - the goal, obviously is to eat 100% unprocessed meals with 30g+ of protein per meal 90% of the time.

In case you are asking yourselves, why I am highlighting a study like this, I would like to invite you to think about your friends and family members. How many of them have found their way to physical culture, already? How many of them are eating clean like yourself? And how many of them are fed up of failing time and again with a radical all-or-nothing approach to a "healthy lifestyle"?

Remember, even the small things matter. If you want to help a friend or family member to make a change, start them out on the  NSSRT-10,000 approach: No snacks, enough sleep and regular exercise; with the latter being as little as a 5,000-10,000 steps a day + thee full body workouts per week which consist of 3-5 body-weight circuit of squats, push ups, and burpees with a build in progression of +1 "rep" of squats + push ups + burpees per week and an additional set (max. 5) every two months.

If you also manage to have him cut out all processed foods from his / her diet progressively, while increasing his / her protein intake to 30g per meal, you and your friend / family member will be surprised about the changes the will see in the mirror after only 6 months.

And if there is one thing you must always remember, it's to never ask too much at once. There is nothing that reduces adherence to diet and exercise programs as much as feeling overwhelmed. The changes have to be feasible and they must look feasible. 

Take a baby-step approach, commend every step on the way and encourage your friend or family member to get back on the wagon, whenever he or she falls off or feels as if he or she had fallen off the wagon, and you will succeed. The change won't happen overnight, but in contrast to the notorious all-or-nothing approach, it will happen.

Reference:

• 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).

Sleep Quickie: Sleep Restriction ➲ Blood Amino Acid Levels ￪, Glucose Levels ￬ ✰ Food ↻ Sleep & Exercise Interactions ✰ Melatonin, A Safe Sleep Aid W/ Anti-Alzheimer's Effects

The healthy lifestyle rhythm: "Sleep, eat, train, live, sleep,..." × 365 days/year

If you were expecting any obscenities in today's "Sleep Quickie", you will probably be disappointed to hear that this article is solely about sleep, metabolism and melatonin and how all that relates to "shutting your eyes and disappearing into the land of dreams".

This means that it won't touch on the 19% increase in copulatory efficiency and the other "significantly facilitated" aspects of sexual activity (mounting latency -80%, ejaculatory latency -63%, etc.) scientists from the University of British Columbia observed in melatonin treated (4 mg/L of drinking water) Long-Evans rats (Brotto. 2002).

Rather than that we are going to focus on the non X-rated semantics of "to sleep", its health effects and the role of melatonin in sleep, health and disease. So, let's see what we've got in stock for you:

• Profound effects of sleep restriction on the human plasma metabolome (Bell. 2014) -- In spite of the the fact that it is well established that short sleep durations and/or poor sleep quality induce changes in our energy and substrate metabolism (Penev. 2012) that increase your risk of developing diabesity (Cappuccio. 2010), we know very little about the biochemical signatures involved in the pathogenesis of type 2 diabetes[5–9].
  
  
  How bad is bad sleep? That's a pretty good question and if we put faith in the latest meta-analyses by researchers from the University of Warwick and the University of Naples Medical School, it's pretty bad - at least that's what I would call something that is associated with increases in ...
  

  • diabetes - 28% increased risk with sleep duration ≤5–6 h/night, 48% increased risk with difficulty in initiating sleep, and 84% increased risk with difficulty maintaining sleep (Cappuccio. 2010),
  • cardiovascular disease - 48% increased risk of developing or dying of CHD with short sleep durations (≤5–6 h/night), and 38% increased risk of coronary heart disease , 65% increased risk of stroke, and 41% increased risk of for any form of CVD with long duration (>8h/night) sleep (Cappuccio. 2011),
  • all-cause mortality - 12% higher all-cause mortality risk for short duration of sleep (≤5–6 h/night), +30% all-cause mortality risk with long-duration sleep (>8h/night) (Cappuccio. 2012)

  Looks pretty bad, right? That's just what I said.
  Bell et al. did thus decide to use a metabolomic profiling approach to assess the impact of recurrent sleep restriction on human intermediary metabolism to identify biochemical signatures that may reflect the effects of sleep curtailment on metabolic risk. To this ends, each study participant completed two 8-night inpatient sessions with restricted (5.5-h time-in-bed) vs. adequate (8.5-h time-in-bed) sleep opportunity while daily food intake and physical activity were carefully controlled.
  
  The subsequent combination analysis of 362 biochemicals in fasting plasma samples that were collected from study participants the morning after each 8-night sleep treatment revealed that..
  1. the relative concentrations of 12 amino acids and related metabolites were increased when sleep was curtailed
  2. sleep restriction also induced elevations in several fatty acid, bile acid, steroid hormone, and tricarboxylic acid cycle intermediates, and surprisingly
  3. the circulating levels of glucose, some monosaccharides, gluconate, andfive-carbon sugar alcohols tended to decline when sleep was reduced.
  According to the researchers the elevation in plasma amino acids (~6-70%), specifically isoleucine, tryptophan, phenyllactate, a byproduct of the phenylalanine metabalism,  glutaroyl carnitine, byproduct of the lysine metabolism, histidine and threonine. If these changes are corollary or causally involved in the increased diabesity risk we see in sleep deprived indiviudals is yet something the researchers cannot tell us, yet.
  
  Incidentally, the same is true for the answer to the question whether similar changes would have been observed if the hitherto healthy, lean subjects didn't have a parenteral  history of type 2 diabetes. The Bell study must therefore be seen as a first in a series of studies that could broaden our insights into the role of abnormal sleeping patterns in the etiology of type II diabetes and other metabolic disease.
• Food ↻ sleep interactions and their potential role in the etiology of diabesity (Chaput. 2013) -- The insights we may gain from the previously discussed study by Bell et al. may give some indication of whether or not the increase in energy intake that's so characteristic for sleep deprived human beings is a crucial, necessary or conditional contributer to the increased diabetes and obesity (=diabesity) risk in this population. 
  
  

  

  Figure 1: Potential mechanisms by which insufficient sleep may facilitate the ingestion of calories (Chaput. 2013)

  In his recent paper in Physiology & Behavior Jean-Philippe Chaput aptly illustrated the six pillars on which this increase in energy intake is based (see Figure 1). Chaput does yet also point out that the ingestion of certain foods / food types, especially those which impact the availability of tryptophan could ameliorate these effects that are mediated by their beneficial effects on (Peuhkuri. 2012) and cites examples such as cow's milk that has has traditionally been considered a tranquilizing beverage with sleep-inducing capacity in many Western countries (an effect that could not be confirmed in scientific studies, cf. Valtonen. 2005; Yamamura. 2007).
  
  Other examples of sleep-promoting foods include herbal products (e.g. chamomile
  tea) and certain fruits (e.g. tart cherries or kiwifruits), but again, robust scientific evidence supporting this is, in many cases, nonexistent (Pehkuri. 2012). And with respect to tryptophan, which is a precursor to the neurotransmitter serotonin and the neuro-secretory hormone melatonin, have only been confirmed in studies using pharmacological doses way above the maximal amount you could get from food. 
• Can exercise attenuate the metabolic effects of dim light at night? (Fonken. 2013) -- You will be aware that going to bed right after an intense HIIT session is beside the point. Your chances of falling to and gettins some restful sleep don't border zero, they are zero. Against that background it may initially sound surprising that researchers from the Department of Neuroscience at the Ohio State University have recently argued that exercise could exert at least part of its beneficial anti-obesity effects by strengthening and realigning the circadian rhythm.
  
  To test this hypothesis Fonken et al. maintained four groups of mice in either dark (LD) or dim (dLAN) nights and provided them with either a functional or a locked running wheel or a locked wheel. As it turned out, "[m]ice exposed to dim, rather than dark, nights increased weight gain." If the mice had access to a functional running wheel, however, the dim light at night hat no effect on their body mass.
  
  This sounds fantastic. Unfortunately, the effect was not brought about by a preventive effect exercise may have on the dim-light-induced defect of the animals circadian system. It was brought about by an increase in energy consumption by the means of which the rodents compensated for the increases in daytime food intake.
• Melatonin supplements work and won't lose efficacy over time (Ferracioli-Oda. 2013) -- In view of the fact that the classics, i.e. milk and camomile tea obviously don't do much to improve your sleep quality (see previous paragraph), it's all the more important to emphasize that Eduardo Ferracioli-Oda, Ahmad Qawasmi, and Michael H. Bloch's meta-regression analysis that examined the influence of dose and duration of melatonin on reported efficacy yielded results all the melatonin lovers out there will certainly appreciate.
  
  

  

  Figure 2: Restoring reduced melatonin levels (A,B,C) to youthful levels by supplementation (1-3) counters the build-up of ameloid plaque (➲Alzheimer's; cf. Lahiri. 2004).

  The Yale scientists analyzed data from 1683 subjects (19 trials) and were able to demonstrate that the supplemental provision of melatonin ...
  1. reduces sleep latency by t = 7.06 min
  2. increases total sleep time by t = 8.25 min
  3. promotes overall sleep quality (+22%)
  In that, it's quite amazing that the efficiency increases in a both dose- and time-dependent manner. In other words, the ability of melatonin to decrease sleep latency and increase your total sleep time increases the more you take and the longer you stay on a supplementation regimen that mimics the natural diurnal melatonin rhythm.
  
  The often-heard hypothesis that you could build up a tolerance over time is thus not supported by scientific evidence. And dependence, as it is common with benzodiazepines is not an issue (Srinivasan. 2011)

In view of the age-related decline in melatonin production (39% reduction in 51-55 year-olds, 62% reduction in 82-86 year-olds; cf. Bubenik. 2011), it may be worth supplementing for anyone over 60 years - if not to improve sleep quality and duration then for the anti-Alzheimer's effects (Lahiri. 2004; Lin. 2013)

Bottom line: You better make sure you get enough quality sleep, if you don't want to jeopardize your health. If you manage to go to bed "early" every day you will see that after 1-2 weeks you won't even need an alarm clock to get up on 6am, when you went to bed shortly before 10pm the night before... well, assuming that you didn't work out at past 6pm, didn't expose yourself to bright or even worse bright blue light from laptop, iPad or LED TV past 8pm and use ear-plugs to block out all shatter, noise or whatever may wake you up when before 6pm.

If all these tips don't help you sleep and/ or you have 5 or 6 decades of extra years under your belt, it may be worth investing in a bottle of 3-10mg melatonin capsules. Avoid the slow-release preparations (unless you like being drowsy the next morning) and take them 1h before you go to bed.

References:

• Bell, Lauren N., et al. "Effects of sleep restriction on the human plasma metabolome." Physiology & behavior 122 (2013): 25-31.
• Brotto, Lori A., and Boris B. Gorzalka. "Melatonin enhances sexual behavior in the male rat." Physiology & behavior 68.4 (2000): 483-486.
• Bubenik, G. A., and S. J. Konturek. "Melatonin and aging: prospects for human treatment." Journal of Physiology and Pharmacology 62.1 (2011): 13.
• Cappuccio, Francesco P., et al. "Quantity and Quality of Sleep and Incidence of Type 2 Diabetes A systematic review and meta-analysis." Diabetes Care 33.2 (2010): 414-420.
• Cappuccio, Francesco P., et al. "Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies." Sleep 33.5 (2010): 585.
• Cappuccio, Francesco P., et al. "Sleep duration predicts cardiovascular outcomes: a systematic review and meta-analysis of prospective studies." European Heart Journal 32.12 (2011): 1484-1492. 
• Fonken, Laura K., et al. "Exercise attenuates the metabolic effects of dim light at night." Physiology & behavior 124 (2014): 33-36.
• Lahiri, Debomoy K., et al. "Dietary supplementation with melatonin reduces levels of amyloid beta‐peptides in the murine cerebral cortex." Journal of pineal research 36.4 (2004): 224-231. 
• Lin, Li, et al. "Melatonin in Alzheimer’s Disease." International journal of molecular sciences 14.7 (2013): 14575-14593.
• Peuhkuri, Katri, Nora Sihvola, and Riitta Korpela. "Diet promotes sleep duration and quality." Nutrition Research 32.5 (2012): 309-319.
• Penev, P. D. "Update on energy homeostasis and insufficient sleep." Journal of Clinical Endocrinology & Metabolism 97.6 (2012): 1792-1801. 
• Srinivasan, Venkatramanujan, et al. "Melatonin agonists in primary insomnia and depression-associated insomnia: Are they superior to sedative-hypnotics?." Progress in Neuro-Psychopharmacology and Biological Psychiatry 35.4 (2011): 913-923.
• Valtonen, M., et al. "Effect of melatonin-rich night-time milk on sleep and activity in elderly institutionalized subjects." Nordic Journal of Psychiatry 59.3 (2005): 217-221.
• Yamamura, S., et al. "The effect of Lactobacillus helveticus fermented milk on sleep and health perception in elderly subjects." European journal of clinical nutrition 63.1 (2007): 100-105.

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. 2012 Sep 15.