Boca Health


Sleep and Successful Weight Loss


We discussed the role of Leptin and Ghrelin in regulating appetite and subsequently body weight in our last article. However, given that both Leptin and Ghrelin are hormones, it’s not surprising that food consumption is not the only factor that matters. Other bodily cycles contribute to their relative concentrations, for instance, circadian rhythms have been shown to affect a person’s Leptin and Ghrelin levels significantly.

Studies reveal that when we go without enough sleep for an extended time, our bodies react hormonally. Subjects that had their sleep severely restricted showed decreased concentrations of Leptin (by 18% on average) and showed increased concentrations of Ghrelin (by 28% on average), (K. Spiegel, et al., “Brief communication: sleep curtailment in healthy young men is associated with decreased leptin levels, elevated ghrelin levels, & increased hunger & appetite,” Annals of Internal Medicine, vol. 141). These numbers have major effects on body weight, because as you’ll recall, Leptin is what signals our fullness and Ghrelin what signals our hunger. When these concentrations become out of whack due to lack of sleep, we tend to overeat simply because our bodies are telling us to.

This same problem occurs when you let your sleep patterns shift away from the ideal "early to bed, early to rise". Night owls who stay up very late, then wake up late in the mornings tend to miss the morning light. This can cause the same problems as too little sleep. If you find yourself waking up after 10 O’clock each day, you are missing out on key light hours and, therefore, decreasing Leptin and elevating ghrelin in your system which can increase hunger and decrease fat burning.

So if you often find yourself sleep-deprived or you get on a time shifted sleep schedule, are you plum out of luck for successful weight loss? Not necessarily. Researchers Mariana Figueiro, Barbara Plitnick, and Mark Rea have found that exposure to light, especially in the morning, can have the reverse effect. Light can actually increase Leptin and decrease Ghrelin in sleep-deprived people. As a result, we highly suggest waking up early and getting outdoors to take in the sunlight. This isn’t a problem for those in sunny South Florida but for those who are farther north, finding morning light can be challenging. The best way to combat this is with a full-spectrum sunlamp. And of course, get enough sleep when time permits.

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