Sleep & Weight Management
Also published in Complete Wellbeing Magazine
By James B. Maas, Ph.D. and Rebecca S. Robbins
Contributions by Rebecca G. Fortgang and Sharon R. Driscoll
Practicing good sleep hygiene, including meeting your individual sleep need every night, is essential for maintaining your weight and a healthy life style. The quantity and quality of your sleep influence the hormonal activity that regulates your appetite. Sleep deprivation and poor sleep habits can disrupt this careful balance, greatly increasing the chance you’ll gain weight and can even put you at risk for obesity.
Obesity: A Growing Concern
Obesity is quickly becoming a serious international health risk. In 2005, 400 million of the global population were obese. The World Health Organization expects this number to jump to 700 million by 2015. In America alone, according to the Centers for Disease Control and Prevention, 65 percent of Americans are overweight, 31 percent are obese, and obesity causes 300,000 deaths each year. Problems with obesity often start with sleep issues and 70 percent of Americans are either moderately to severely sleep deprived.
The University of Warwick Medical School found a correlation between short sleep, a higher body-mass index (BMI) and larger waist circumference over time. Furthermore, researchers at Columbia and the University of Chicago found that people who sleep five hours per night have a 50 percent higher chance of being obese, while those who sleep six hours have a 23 percent greater risk of obesity than their well-rested counterparts.
Granted, the correlation goes both ways; people who are obese often have difficulty sleeping due to discomfort and medical problems such as sleep apnea. This is because excess weight around the neck complicates respiratory functioning, causing heavy snoring, repetitive pauses in breathing, a high risk for hypertension and excessive daytime sleepiness.
Sleep, Food, and Energy: A Triangular Relationship
Every day, we have work to finish, errands to run, people to call, and other tasks and issues that demand our attention. For all of this we need energy, which is provided by both sleep and food. Imagine sleep and food are two donors of the same commodity, energy and it will be clear that a lack of one would demand extra help from the other, and an abundance of one would make the other less crucial. So it is, the closer you get to the recommended 8 hours of sleep each night, the less they feel the need for food to give them energy. When you lose sleep, your appetite goes up to compensate, leaving you susceptible to weight gain.
Getting to the Bottom of Sleep and Weight: The Role of Hormones
Some scientists have been asking the obvious question: We know that sleep and food are both related to our feeling of energy, but why this strong connection between amount of sleep at night and body weight? Many have looked to hormones to try to get to the bottom of this relationship. Hormones are our bodies’ long-range messengers – our postal workers. They are chemicals that are released by cells in one area and then can travel and send messages to other areas, often traveling by blood.
How much we eat for energy is largely dictated by the interplay between two of these hormones: leptin and ghrelin. They both fight to influence how hungry you feel, but leptin is a long-term regulator, while ghrelin seems to influence short-term sensations of hunger or satiation
Ghrelin is the only hormone we know of that is orexigenic, or stimulates feelings of hunger. It is produced in the lining of the stomach, pancreas, and other peripheral tissues, and it sends messages to a region of the brain called the hypothalamus. Its levels fluctuate depending on how much eating occurs. Essentially it is a short-term meal initiator to regulate energy balance, and levels rise before meals and fall right after them.
In humans, ghrelin concentrations are negatively correlated with BMI, meaning that the higher the body mass index, the less ghrelin there is circulating in the blood. This makes sense: the more energy you already have stored, the less your body needs you to eat more. Therefore, as Troels Hansen of Aarhus University Hospital in Denmark and colleagues discovered, obese patients (typically characterized by lower than average levels of ghrelin) saw an increase in ghrelin of 12% following weight loss interventions.
Leptin, on the other hand, inhibits food intake. It is produced mostly in adipose tissue (another name for body fat), where it is released into the bloodstream and heads to the brain to report on how much energy the body is storing. While ghrelin makes you hungry now, leptin helps with weight loss in the long term; making you less hungry. Leptin levels are higher among those with a higher BMI and among those with a higher percent total body fat.
Enter, sleep. Researchers Shahrad Taheri, Ling Lin from the Howard Hughes Medical Institute at Stanford University, and colleagues found that shorter sleep is associated with elevated ghrelin and reduced leptin – and, of course, higher BMI. This imbalance increases appetite and slows metabolism. A study by researchers at Stanford and the University of Wisconsin monitored the sleep duration, weight, body fat, and leptin and ghrelin levels of 1,000 volunteers. Those who slept less than eight hours at night had elevated ghrelin and lowered leptin molecules and, alarmingly, higher body fat.
Still not convinced? The University of Chicago determined that even among healthy men and women with average BMIs, those who slept less than six hours per night experienced hormonal changes that could affect their future body weight and overall health. This is because short-sleepers produce 30 percent more insulin than normal sleepers in order to maintain regular blood-sugar levels, predisposing them to weight gain. Another important factor to consider is sleep and cortisol levels, also known as stress hormones. Insufficient sleep triggers the release of additional cortisol that can also stimulate hunger.
Lose Weight by Sleeping More
When sleep deprived, we crave sugary and high-calorie foods. In one study of 12 healthy males, the University of Chicago found that, when subjected to sleep deprivation, not only did leptin levels go down and ghrelin levels sky-rocket but cravings for high carbohydrate, calorie-dense foods increased 45 percent.
There are, of course, various factors out of our control that contribute to our body shapes and sizes and our appetites such as stress, diet, exercise, and genetics. However, for many of us, instead of a snack, we may actually need some shuteye. Once you understand this, you can begin to use sleep to control and even lose weight.
Overall, it’s clear: sleep is crucial to regulating your appetite and metabolism and plays a key role in any healthy weight management program . In addition to practicing good sleep habits (such as meeting your nightly requirement of 7.5 to 8.5 hours of sleep and maintaining a regular sleep/wake schedule), the below healthy diet tips will improve your sleep. In so doing you’ll improve your ability to maintain your weight and live a healthy lifestyle!
Tips for Sleep and Weight Management.
- Eat most of your calories during the morning and early afternoon. The old adage ‘eat a breakfast of kings, lunch of princes, and dinner of paupers’ is an excellent guide. Eat the majority of your calories, particularly proteins, before the evening. Have a light meal at dinner and save room for a light, pre-bed snack.
- Eat a dinner of mostly grains and vegetables. For dinner choose a light, yet satisfying meal of hearty leafy green vegetables such as kale and rice or easy-to-digest hummus with vegetables.
- Avoid all caffeine after 2PM.
- Enjoy a light snack 45 minutes before bed. Choose foods containing L-tryptophan as they are useful for promoting sleep due to their serotonin-inducing properties (serotonin is the neurotransmitter involved in initiating sleep). Simple, easy to digest carbohydrates such as crackers, half a banana, or a handful of non-sugary cereal are best.
- Avoid large meals and spicy foods before bedtime. These will increase gastrointestinal activity and disrupt sleep.
Dr. James B. Maas is a sleep educator/researcher who helped develop the Dr. Maas Sleep for Success line of pillows and comforters for United Feather and Down. He served for 48 years as professor, chair of Psychology and Weiss Presidential Fellow at Cornell University. He lectured about sleep to more than 65,000 undergraduates, several of whom are now sleep doctors.