A decomposing body will normally smell like rotting flesh with fruity undertones. Bacterial interactions as the body breaks down. The online news magazine The Independent and the website Sciencemag wrote about research at Body Farm in Tennessee aimed at isolating putrescine and cadaverine emitted by humans from those caused by animal decay. You'll know it when you smell it.
Burning muscle tissue gives off an aroma similar to that of beef in a pan, and body fat smells like a garnish of greasy grilled pork. But you probably don't confuse the scent of human remains with an outdoor meal. This is because the whole body includes all kinds of parts that we would rarely use for a normal barbecue. For example, cattle bleed to death after slaughter, and the beef and pork we eat contain few blood vessels.
When an entire human body burns, all the iron-rich blood remaining inside can give the smell a coppery metallic component. Whole bodies also include internal organs, which rarely burn completely due to their high fluid content; they smell like burnt liver. Firefighters say the cerebrospinal fluid burns in a sweet, musky scent. It definitely smells like food, but when it's just raw meat, it doesn't really smell like much.