A new study may help explain why individuals with narcolepsy tend to gain weight even when they eat less than the average person (Sellayah D et al. Cell Metab. 2011;14:478-479).
An association between obesity and narcolepsy was first noted about 8 decades ago. Patients with narcolepsy are often deficient in the neuropeptide hormone orexin, which encourages hunger and wakefulness. This deficiency may be the result of impaired energy-burning brown fat. (While white fat stores calories, brown fat burns them, generating heat in the process.)
Hampton T. Narcolepsy and Weight Gain. JAMA. 2011;306(21):2315. doi:10.1001/jama.2011.1743