Absolutely! As much as we don’t want to believe it, not enough shut eye can make you fat.
Leptin, Ghrelin, and Your Appetite
Ghrelin and leptin are peptide hormones that control your hunger level. Ghrelin tells you to start eating, leptin tells you it’s time to stop.
Ghrelin is secreted by your stomach, hypothalamus, and other parts of your endocrine system in response to an empty stomach. It signals appetite and encourages fat accumulation to keep you from wasting away from lack of food.
Leptin is secreted by your adipose tissue. It signals to your brain (via the hypothalamus) to suppress your appetite and increase your activity levels.
So if you accumulate a bunch of body fat then you should be getting signals to quit eating, right?
Well it’s not that simple. If you accumulate too much body fat, you become “leptin resistant.” This means the brain receives so much leptin signaling that it stops listening and never receives the message that you’re full, so you keep eating. The ghrelin gets you eating, and chronic leptin elevation makes you overeat.
We need ghrelin and leptin working in balance to drive ideal body composition:
- Too much ghrelin and we don’t stop eating (because there’s a constant feeling of hunger).
- Too little leptin and we don’t stop eating (because there’s no signal to stop).
- Too much leptin over time, we don’t stop eating (because we develop leptin resistance).
Therefore, any disruption to your leptin and ghrelin levels is a problem — and it turns out that lack of sleep is a huge disruptor.
Ghrelin and Lack of Sleep
In a landmark 2004 study of 1,040 participants’ sleep habits, Emmanuel Mignot of the Stanford Center for Sleep Sciences and Medicine found that an ongoing lack of sleep was correlated with increased ghrelin levels and reduced leptin levels.
The study found a u-shaped relationship between sleep duration and body mass index. Among the participants, minimum BMI was seen with an average of 7.7 hours of sleep per night, with BMI increasing proportionally for all sleep times less than 8 hours. Interestingly, the study showed that oversleeping is associated with higher BMI levels, as well.
In summary, the less participants slept:
- The less leptin they produced
- The more ghrelin they produced
- The greater their BMI
Impressively, the finding was statistically valid even after adjusting for the age and sex of the participants, and has been replicated by several other studies, including a study that found that as little as one night of sleep deprivation (decreasing from 7 to 4.5 hours) was associated with increased ghrelin levels as well as self-reported hunger.
The Fat Loss Lesson
Sleep plays a key role in regulating your hunger hormones. Therefore, if you want to positively influence your body composition, the first thing you should do is make sure you’re getting the ideal amount of sleep (between 7-8 hours every night). This will ensure that your leptin and ghrelin levels don’t get out of whack, keeping you in the ideal balance between hunger and satiety.
Upcoming Event
Gymnastics Clinic
When: Saturday, June 3rd 12p-3p
Where: CrossFit 626
What: In this clinic you will learn a unique approach on how basic gymnastics can apply to all movements we use in CF in order to increase movement efficiency across the board. Although our primary focus is on the gymnastic limbs of CF we will discuss how these movements relate to weightlifting and mono-structural pieces in order to deepen the understanding of all mechanics as they relate to human movement. You will leave this workshop style class feeling inspired and ready to put it to practice. All levels are welcome although an understanding of CF fundamentals is expected.
How: REGISTER HERE!
Workouts for Week 05.22.17
Monday: Arnold Press / Lunges; Kettlebell Swings / Toes to Bar / Push Ups
Tuesday: Snatch High Pull; Hang Power Clean / Burpees / Assault Bike
Wednesday: Front Squat / Pull Ups; Row / Squats / Burpees; Leg Raises / External Rotation
Thursday: Push Press / Overhead Squat; Thrusters / Run
Friday: Turkish Get-Up / Hip Extension / Ring Rows; Run / Ball Slams / Russian Twist
Saturday: Front Squats; Row / Squat Clean / Push Ups