How proper sleep helps you to lose weightSleep restriction has multiple effects on your ability to lose weight. Poor and/or restricted sleep duration leads to an approximate 20% decrease in leptin levels(1). Leptin is a hormone secreted by fat cells that tells you when to stop eating. A drop in leptin levels will cause you to eat more food than you normally would because your brain doesn't get the signal that you are full. In theory, a 20% drop in leptin levels should lead to an increased consumption of between 350-500 cals per day for an average male(1); this approximates a 30-45lbs weight gain per year. Since most of the studies are done with calories held constant under laboratory conditions, we can only guesstimate as to the amount of weight these levels of leptin could generate.
People with insulin resistance and type 2 diabetes tend to have leptin resistance, a situation where leptin levels are high, but the brain doesn't respond to it. Leptin signaling is affected by insulin resistance and cells that are constantly bombarded by both of these hormones tend to downregulate receptors to them on their cell membrane. This leads to constantly high circulating levels of both insulin and leptin which is highly inflammatory and compounds the problem of systemic inflammation even further. Since the cells in the hypothalamus that regulate appetite are not listening to the signal from leptin, these people get the same effect as sleep deprived people do. It's not that they are always hungry, it's that they don't know when to stop eating because the communication system that sends that signal is malfunctioning.
Sleep also affects many other aspects of your health that impact your ability to lose weight. A single night of sleep deprivation has been shown to induce insulin resistance in multiple pathways (2). Other studies have shown reduced insulin sensitivity(3, 4) as well as significant increases in the stress hormones epinepherine and norepinepherine (3) during periods of sleep deprivation ranging from 7 to 14 days. In the shorter study, researchers looked at what happened at a genetic level during 7 days of sleep restriction. The researchers designed the study in a way that would emulate real world conditions in the Western world. During the sleep restricted portion of the study participants slept an average of 5.7 hours per night for a week while in the sleep sufficient portion of the study the participants slept an average of 8.5 hours per night for a week. The sleep deprivation duration is highly comparable to real world conditions as 30% of American workers indicate they sleep 6 hours or less per night and many night shift workers get less(5).
In this study, there were 711 genes expressed differently during sleep restriction compared to sufficient sleep(4). These genes were involved in sleep regulation and circadian rhythm, immune system/inflammatory response, metabolism, and the stress response. In addition, oxidative stress increased in the sleep deprived state as did insulin resistance. In the sleep deprived state, all of these genes were differentially expressed in a way that would negatively impact health and your ability to lose weight, including increased triglyceride levels. Recall from the last bog that triglyceride levels are important as high triglyceride levels in the blood are indicative of a reduced ability to break down fat for energy, your primary goal when trying to lose weight. So how does stress play in to this and how can understanding the stress response help you lose weight?
The Autonomic Nervous SystemYour stress response is handled by a part of your nervous system called the Autonomic Nervous System (ANS). Your ANS has 2 branches, the sympathetic and the parasympathetic. The sympathetic branch of the ANS is responsible for the fight or flight response while the parasympathetic branch is responsible for rest and digest. Your ANS basically partitions your resources to the more needed processes based on how you perceive your situation. When you perceive a situation as stressful or you send signals to your body that indicate stress, the autonomic nervous system increases sympathetic activity which causes blood to flow away from organs of digestion and to your muscles so that you can respond to the stressor. In addition, heart rate and blood pressure increase as well as respiration rate. When a stressor is resolved or you begin to send signals to your body that the stressor is over, parasympathetic activity increases and heat rate, blood pressure, and breathing rate decline back to normal and blood flows back to the organs of digestion so you can recover from the stress.
Unfortunately, we are in a society that is stressful 24/7/365. The stress doesn't need to be physical either, how you perceive the situation is just as important. Worrying about bills, getting a job, passing finals, and breaking up with a significant other may not warrant a physiological change that partitions resources to fighting or fleeing, but that's precisely what happens whether the stress is real or perceived. This is because the amygdala, the emotional center of your brain, has a direct connection to the hypothalamus. In addition to regulating most every process in your body including appetite, the hypothalamus initiates the stress response by increasing sympathetic nervous system activity. Over time, chronic activation of the sympathetic nervous system can lead to digestive issues as well as depressed immune function as the body constantly tries to respond to a stress that is never there. This can lead to big problems because if you cannot digest or absorb your food properly, the vital nutrients your body needs to function properly will not get to your cells.
In addition, a chronically activated stress response prevents you from relaxing and falling asleep, which further impairs you ability to enter a parasympathetic state. Forget trying to lose weight, at this point your health is probably deteriorating pretty rapidly and you need to hold on to everything you've got to make sure you survive. Your body doesn't know that the late rent check isn't going to kill you, it perceives it as a life or death situation regardless. A body under this kind of stress will not budge if you are trying to lose weight.
The question now becomes, "What activities will get me in to this situation and which activities will get me out?" To answer the first question, the biggest contributor is probably poor stress management. Not dealing with stress is a terrible way of trying to deal with it as it never goes away and that is the tack most people take. Other frequent contributors to this state are poor sleep, binge drinking, high caffeine consumption, over-exercising, having a job where you have little control and high or low demand, a long commute to work, and poor nutrient quality in the diet. Things that help you get out of this situation include dealing with stress, getting 8 hours of quality sleep a night, meditation, tai chi, yoga, stretching, massage, getting proper nutrition, laughing often, and trying not to put yourself in to stressful situations. One thing I've found to be very helpful for people who have long commutes to work is to listen to stand up comedy on the way to work.
In our program we utilize a stress bank account where you have withdrawals (Stressors) and deposits (De-stressors). Finding a balance that works for you is key in helping you learn how to lose weight. Making sure every withdrawal is matched with a deposit will go a long way in helping you achieve your weight loss goals.
ConclusionAll of the variables we have discussed up to this point that are important in teaching you how to lose weight will impact your body's stress response system in some way. One of the best ways to make sure your body is recovering from stress and not tipping toward too much sympathetic nervous system activity is to get adequate, high quality sleep. Doing this will help regulate your appetite, allow you to deal with the stressors you encounter every day, and provide the optimal internal environment to help you lose weight.
In the part 7 of this series found here, I will discuss exercise and it's role in how to lose weight.