No abstract

High-fat diets produce obesity in part because, per calorie, glucose produces greater post-prandial thermogenesis than lipids, an effect probably mediated by glucose-sensing neurons. A very low carbohydrate/high-fat/high-protein Atkins-type diet produces obesity but is marginally ketogenic in mice. In contrast, high-sucrose/low-fat diets, and very low carbohydrate/high-fat/low-protein (antiepileptic) ketogenic diets reverse diet-induced obesity independent of caloric intake. We propose that a non-ketogenic high-fat diet reduces glucose metabolism and signaling in glucose-sensing neurons, thereby reducing postprandial thermogenesis, and that a ketogenic high-fat diet does not reduce glucose signaling, thereby preventing and/or reversing obesity. Keywords obesity; low-carbohydrate diets; high-fat diets; ketogenic diets Do low carbohydrate diets promote or reverse obesity?"A systematic review of low-carbohydrate diets found that the weight loss achieved is associated with the duration of the diet and restriction of energy intake, but not with restriction of carbohydrates." (Astrup et al., 2004) "This review covers evidence from carefully controlled laboratory studies, clinical trials, studies in populations at high risk of developing obesity, and epidemiologic studies on the role of sugars, particularly sucrose, in the development of obesity. Although many environmental factors promote a positive energy balance, it is clear that the consumption of a lowcarbohydrate, high-fat diet increases the likelihood of weight gain." (Saris, 2003) These two statements from recent reviews neatly state the current consensus regarding the effect of dietary composition on obesity. In fact, despite the enormous popularity of lowcarbohydrate diets such as the Atkins diet, the South Beach diet and the Zone diet, the professional consensus is that low-carbohydrate diets (which typically implies high-fat diets) are more likely to produce obesity than reverse obesity. Although several studies have reported that low-carbohydrate diets are slightly better than low-fat diets to reduce body weight over a

COVID-19 has quickly become a worldwide pandemic and is well-known for its pulmonary complications. Dermatologic manifestations such as chilblain-like lesions have been recently described, but it is unclear if they are truly secondary to the infection or not. Here we describe a young patient who developed chilblain-like eruptions on his toes, likely secondary to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We discuss the literature that supports the hypothesis that these are in fact secondary to the infection, as well as provide insight into the pathology of these lesions.

Thionamides, such as methimazole and propylthiouracil, are used for the management of hyperthyroidism. Agranulocytosis is a rare adverse effect of thionamides and elderly patients are especially vulnerable. Here we discuss a case of an 80-year-old woman who developed agranulocytosis and pneumonia approximately 4 weeks after starting low dose methimazole therapy. Despite aggressive treatment with broad-spectrum antibiotics and granulocyte colony stimulating factor, she developed multiorgan failure and died. Our goals are to identify risk factors common to elderly patients and hopefully improve outcomes in this population when prescribed thionamides.