Comparing Strategies for Weight Loss Maintenance

tape measureIt almost seems that a million-and-one books are published everyday touting the secret to rapid and sustained weight loss. But, how many of these diet schemes have been verified to produce the results they advertise? In the latest JAMA (Journal of the American Medical Association) issue, a group of academic centers involved in the Weight Loss Maintenance (WLM) initiative published their results from a three-year study comparing strategies for sustaining weight loss. The project is sponsored by the National Heart, Lung, and Blood Institute (NHLBI), and includes four clinical centers: Duke University, Johns Hopkins University, Pennington Biomedical Research Center, and the Kaiser Permanente Center for Health Research.

The design of the WLM clinical trial involves two phases. Phase 1 comprises a 6-month period where all participants undergo similar intervention to obtain weight loss. Working closely with a trained interventionist, the group strives to achieve a weekly weight loss goal of 1-2 pounds per week through a combination of strategies, such as caloric reduction, dietary modification, and increased physical activity. After having lost weight in phase 1, participants in the 30-month phase 2 trial are randomly divided into three groups, each with a different level of intervention to encourage maintenance of weight loss: 1) minimal intervention; 2) technology-based intervention, with use of an interactive website which sets personal goals, action plans, and provides an online support community; and 3) personal-contact intervention, involving monthly contact with a weight-loss interventionist.

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Inaccurate Alcohol Breath Test

red wineImagine this far-fetched hypothetical scenario where an overworked, sleep-deprived, and hypoglycemic post-call resident is driving home (unbelievable, huh?). During a brief moment of weakness, he drifts to the right, but rapidly corrects his driving trajectory. However, a highway patrolman, Officer Poelis, is sitting along the shoulder of the road and notices the momentary lapse in the driver’s control. Sirens blare and the resident stops his car. Given the circumstances, the resident’s erratic driving behavior probably resulted from his prolonged lack of food and sleep. Officer Poelis, however, suspects that alcohol is involved and asks the resident to take a breath test. To the resident’s shock and surprise, he tests positive for alcohol despite not having had any alcoholic beverages since the last Residents Night Out party two weeks earlier.

Although a seemingly stretched hypothetical scenario, it is not beyond the realm of possibility. A Swedish group recently published a case report of a 59 year-old non-drinker who was unable to start a motor vehicle equipped with an alcohol ignition interlock device. A second breath-alcohol test revealed a blood alcohol level of 0.01-0.02 g/dL. These results were shocking, considering the gentleman has remained abstinent from alcohol his entire life.

There is nevertheless a biochemical explanation for the false alcohol reading. In an attempt to lose weight, the patient was on a very low calorie diet (VLCD). People on such diets or prolonged fasting states depend on fat metabolism for energy. Three forms of ketone bodies (acetone, acetoacetate, beta-hydroxybutyrate) subsequently accumulate in the body. The acetone can be metabolized by the liver to form isopropanol. A drawback of the breath-alcohol analyzer is that it cannot differentiate isopropanol from ethanol (the form of alcohol found in liquor). Consequently, despite the lack of substance use, he was recorded to have had an elevated concentration of alcohol in his breath.

Fortunately, blood alcohol tests utilize gas chromatography, which generate more specific results. This method could be used to verify false positives, but I doubt we will see bulky gas chromatograms in squad cars anytime in the near future.

Since this is the first case report of its kind, it is still unclear whether prolonged fasting states relate to a false positive reading. Besides the obvious warning to not drink and drive, I would strongly discourage the use of this excuse if caught. It would be much easier and safer to just find a designated driver. In the case of a resident on q4 call, finding a willing volunteer may be more difficult to accomplish.

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Does Melatonin Work? Is It Safe?

moonlightMelatonin is a hormone produced by the pineal gland and associated with regulation of the sleep cycle. There have consequently been melatonin products, and biosynthetic variants (i.e., ramelteon), marketed as sleep aid products. A popular use for melatonin has been to combat jet lag or for adaptation to different time zones. Two recurring questions I have encountered regarding melatonin are whether it actually works and whether there are any adverse side-effects.

The February 10 issue of the British Medical Journal includes a study by a Canadian group that reviewed the efficacy and safety of melatonin use with secondary sleep disorders and sleep restriction. Secondary sleep disorders are sleep problems with a physiologic cause, such as hyperthyroidism or substance abuse (toxicity). Sleep restriction, on the other hand, results from voluntary sleep disruption. On-call physicians or third-shift police officers are examples of people who endure sleep restriction.

According to the meta-analysis (a review of several research efforts examining the same topic) of 15 separate studies (524 participants), melatonin is not effective for both secondary sleep disorders and sleep restriction. Commonly reported side-effects were drowsiness, headache, nausea, and dizziness. Otherwise, the report does not indicate significant adverse effects of short-term melatonin use (3 months or less).

In another meta-analysis performed by the same group, and published two months earlier in the Journal of General Internal Medicine, there is some evidence of efficacy in delayed sleep phase syndrome (DSPS), a shift in the circadian rhythm that makes it difficult for the person to fall asleep and wake up. Study participants who suffered from this disorder were able to fall asleep around 38.8 minutes earlier with melatonin. The study does not however report significant improvement in sleep onset with melatonin use for other sleep disorders. The findings on safety are similar here as in the BMJ article.

In short, melatonin is not effective for most sleep disorders, but it is safe with short-term use.

  • Sources
  • Buscemi N, Vandermeer B, Hooton N, Pandya R, Tjosvold L, Hartling L, Baker G, Klassen TP, Vohra S. The efficacy and safety of exogenous melatonin for primary sleep disorders. A meta-analysis. J Gen Intern Med 2005;20:1151-8.
  • Buscemi N, Vandermeer B, Hooton N, Pandya R, Tjosvold L, Hartling L, Vohra S, Klassen TP, Baker G. Efficacy and safety of exogenous melatonin for secondary sleep disorders and sleep disorders accompanying sleep restriction: meta-analysis. BMJ 2006.

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