Irregular Sleeping and Eating Patterns Slow Metabolism and Boost Appetite

August 23, 2012 No Comments by Scott Isaacs, M.D.

It is well known that when people don’t get enough sleep, they eat more calories than when they’re well rested. Poor quality sleep stimulates hunger hormones boosting appetite and increasing cravings for unhealthy comfort foods like ice cream and fast food. Sleep problems also cause insulin resistance, especially in brain cells. Sugar can’t get into brain cells, which leads to sugar cravings.

The body has a built-in biological time clock that influences most of our basic functions including the sleep and wake cycle. The hypothalamus, which regulates hormone production through the pituitary gland, also contains the master circadian clock. Organs throughout the body, including fat cells, the stomach and intestines, liver, heart, eyes and the immune system have their own circadian clocks. Glands like the thyroid gland, adrenal gland, testicles and ovaries also have their own clocks which are responsible for the natural rhythms of hormones throughout the day. A healthy balance of hormones requires all of the body’s clocks to be synchronized. Anything that disturbs the biological timekeeping system can have a detrimental impact on hormones, metabolism and weight.

Many people who work outside of traditional hours have a disrupted sleep-wake cycle. When there are chronic or episodic periods of disturbed sleep, the circadian rhythm is affected, causing a misalignment between the brain and the body. Hormonal problems leading to weight gain and slow metabolism can occur when the biological clock is out of sync. The hypothalamus, which controls the body’s master gland, the pituitary gland, is also responsible for maintaining the body’s circadian rhythms. The hypothalamus synchronizes the brain with the body, maintaining the proper ebb and flow of various hormones throughout the day and night.

Melatonin and cortisol are two hormones important in the sleep-wake cycle. Melatonin, produced by the pineal gland in the brain, increases about 2 hours before bedtime and decreases shortly before waking. So normally, melatonin levels are low during the day and higher at night. If sleep or waking up occurs at the wrong time, melatonin can be too high or too low. The circadian clock must be reset on a daily basis. Melatonin, light and darkness help keep biological rhythms in sync.

A new study by Dr.  Hanne KJ Gonnissen and colleagues published in the American Journal of Clinical Nutrition highlights the effects of the effects of irregular sleeping and eating patterns on calorie burning, appetite, and hunger hormones. The subjects in the study lived in a clinical research center and were subjected to alterations in their sleep wake cycle and meal times. Sleep, energy expenditure, substrate oxidation, and appetite were quantified. Blood and saliva samples were taken to determine melatonin, glucose, insulin, ghrelin, leptin, glucagon-like peptide 1 (GLP-1), and cortisol concentrations. The main effect of sleep alterations is a concomitant disturbance of the glucose-insulin metabolism. The authors concluded that chronically eating and sleeping at unusual times can create a health risk through a metabolic disturbance.

Read the abstract in the American Journal of Clinical Nutrition

For more information on how sleep patterns affect your appetite and metabolism, please read my book Hormonal Balance: How to Lose Weight by Understanding Your Hormones and Metabolism or visit my Facebook page.


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