Do mosquitoes prefer fat or skinny people?

Mosquitoes do not prefer fat or skinny people based on body weight alone, but they are attracted to factors correlated with body size like carbon dioxide output, body heat, and skin surface area, so larger people may be bitten more often because they exhale more carbon dioxide and produce more heat and have more skin area. Mosquitoes locate hosts by detecting carbon dioxide from breath, body odors like lactic acid and ammonia from sweat, and body heat, and larger individuals and those who are overweight may exhale more carbon dioxide and have higher metabolic rate producing more heat and sweat, which can attract more mosquitoes. Pregnant women are bitten more due to higher carbon dioxide and body temperature. However, skinny people who are physically active and sweating heavily, or who have certain blood types like Type O that studies suggest may be slightly more attractive, or who have more skin bacteria producing attractive odors, can also be bitten more. Mosquitoes also prefer people with higher skin temperature and those wearing dark clothing. So mosquitoes do not consciously choose fat vs skinny, but they are more attracted to people who produce more carbon dioxide, heat, and sweat, which often correlates with larger body size, but individual differences in skin odor, blood type, and activity level are more important than weight alone, and both fat and skinny people can be heavily bitten depending on these factors.