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.
Divide these numbers by 4 -- carbohydrates have 4 calories per gram -- to convert calories from carbs into grams of carbohydrates. If 1,800 calories daily is your usual intake, for example, you can have 810 to 1,170 calories from carbohydrates, which is about 203 to 293 grams of carbohydrates.arbohydrates arenât something you should limit in your diet. They turn into your bodyâs main source of fuel -- glucose -- during digestion, making them an essential part of your daily calories.