“Biological Clock” Affects Hunger and Appetite

Epidemiology studies have consistently found a correlation between obesity and short sleep time while other studies have correlated both short and long sleep time with obesity. These studies have been widely reported in the popular press. Unfortunately, these studies are in conflict with most animal studies which have shown weight loss associated with total or partial sleep deprivation.

A recently published article in the journal Obesity gave insight into this discrepancy. The results were also consistent with the hypothesis proposed in Practical Health Strategies’ ebook: “Lose Weight for your Sleep Apnea” available on Amazon.com.

This article reports the effect of thirteen days of forced desynchrony on twelve, non-obese adults. Forced desynchrony is an experimental tool in which the sleep/wake cycle is forced out of phase with the internal biological clock located in the hypothalamus of the brain. The forced desynchrony in this protocol consisted of the subjects living on a 20 hour “day” schedule rather than a true 24 hour day. The subjects followed a normal (24 hour day) fixed sleep/wake schedule for two to three weeks prior to the desynchrony protocol and were maintained in constant but low level light throughout the desynchrony to assure a stable internal clock. The cycling of the internal biological clock was tracked by monitoring the core body temperature. Thus, the sleep/wake cycle in the 20 hour behavioral day was out of phase with the internal biological clock and the phase shift increased over the duration of the study.

Meals were designed to maintain energy balance and for constant macronutrient distribution: 60% carbohydrate, 24% fat, and 16% protein. At regular times the subjects rated their hunger, appetite, and food preferences.

The results revealed a strong circadian, biological clock, rhythm in hunger, appetite, and preference for sweet, starchy and salty foods peaking in the biological evening time and minimal in the biological morning. This was independent of the time since last meal, time since awakening, and calories consumed. By contrast there was no circadian linked preference in vegetables.

The authors compared the results to the two-process model of sleep regulation as covered in the “Lose Weight for your Sleep Apnea” ebook. This study may help explain the inconsistency in animal sleep deprivation studies, which show weight loss, and epidemiology studies, which show weight gain.

Practical Health Strategies (www.practicalhealthstrategies.com), offers wellness programs in the Pensacola and Mobile area, and throughout north Florida, and south Alabama, Georgia, and Mississippi. Practical Health Strategies offers Wellness Plans you can Live With!

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