It's not an actual virus but the result of dehydration that occurs when switching from glucose to fat for energy. Low-carb diets generally have a diuretic effect within the first few days, meaning you lose more water and electrolytes (like potassium and sodium) in urine than normal. It happens because you're body is losing water as it turns to muscle glycogen for energy and your body’s insulin levels decrease.
What are the 4 types of carbohydrates
^ Jump up to: a b c d e f g h i j k l m n o p q r s Kossoff EH, Zupec-Kania BA, Amark PE, Ballaban-Gil KR, Bergqvist AG, Blackford R, et al. Optimal clinical management of children receiving the ketogenic diet: recommendations of the International Ketogenic Diet Study Group. Epilepsia. 2009 Feb;50(2):304–17. doi:10.1111/j.1528-1167.2008.01765.x. PMID 18823325