Definition. The host (also called the susceptible host) is the human body: someone who is at the risk of infection. Infections do not necessarily occur when pathogens enter the body of the person whose immune system is functioning normally.Whether or not a pathogen will result in infection depends upon several factors related to the host (the person exposed), the pathogen itself, and the environment.nfections do not necessarily occur when pathogens enter the body of the person whose immune system is functioning normally. Whether or not a pathogen will result in infection depends upon several factors related to the host (the person exposed), the pathogen itself, and the environment.
You can find out how many calories are in a food by looking at the nutrition facts label. The label also will describe the components of the food â how many grams of carbohydrate, protein, and fat it contains. Here's how many calories are in 1 gram of each: 1  carbohydrate â 4 calories.  protein â 4 calories.
MedlinePlus reports that carbs and protein each provide 4 calories per gram, and fat contains 9 calories in each gram. For example, if youâve eaten 65 total grams of dietary fat, youâve consumed 585 calories from fat. If youâve eaten 95 grams of protein, youâve consumed 380 calories from protein, and if youâve eaten 250 carb grams, youâve consumed 1,000 calories from carbohydrates. Alcohol â in alcoholic beverages â provides 7 calories per gram, reports the McKinley Health Center.