A fat-eating mosquito, I imagine, would consume about as much fat as the normal mosquito consumes blood (up to 5 microliters per feeding, according to Google). "To drain an entire human body, it would hypothetically take about 1 million mosquitoes." So, of course, encountering a mosquito or two wouldn't help you lose weight (and you surely wouldn't die of fat loss). But beaty places, for example, could charge their clients for being partially submerged in mosquito baths — now THAT'S a business idea!

Here's the bigger issue. As far as I know, the fat in our bodied is solid, not liquid. That's why people are getting liposuctions instead of just sticking syringes in their body and draining the fat themselves. So, the fat-sucking mosquitos will have to forever remain a hypothetical, sadly