Juicing creates liquid foods, which the body can easily assimilate and absorb. It allows the vitamins and other nutrients in fresh fruits and vegetables to be easily consumed — even by people who have no appetite. Raw foods provide abundant energy. They supply the body with optimum nutrition in the form of vitamins, food enzymes and fibre. Juicing is often used if a PHA's health is compromised by weak digestion or malabsorption and if a person has difficulty chewing.

Most fruits have a cleansing effect on the body's system. Their high water content flushes the digestive tract and kidneys. Juicing is used to flush the kidney, liver and gastrointestinal system of toxins. For PHAs dealing with the side effects of antiretrovirals, juicing may assist in removing the toxic by-products of the drugs. These enzymes are naturally present in fruits and vegetables. Proponents of juicing believe that enzymes are destroyed when food is processed or heated. Our own bodies produce enzymes that digest food and incorporate it into the cells of our bodies. Juicing allows us to ingest the enzymes of fruits and vegetables, which may make digestion easier.

The freshest produce will give you the most enzymes. So choose fruits that are in season. To avoid ingesting pesticides, peel the skin of the fruit or vegetable and do not ingest the pulp. Fresh juices are a concentrated form of food. Be moderate in your consumption. Fruit juices are high in fruit sugar.

Different juices are thought to have different effects on our bodies. For example, prunes and apricots are used as laxatives, while bananas are recommended to slow diarrhea. It is also important for PHAs to know that grapefruit juice can affect the concentration of protease inhibitors in the blood, possibly making side effects more severe. Although some PHAs have intentionally used grapefruit juice to increase the levels of drugs that the body absorbs poorly, such as saquinavir, people on protease inhibitors should use grapefruit juice with caution, if at all. You can combine juices so that their benefits work together. The potential effects of fruits and vegetables are discussed in the book Juicing For Life, by Cherie Calbom, Jeffrey Bland and Maureen B. Keane.

In addition to the impact of some juices on the digestive system specifically and the body in general, PHAs may also choose juices according to their colour. (See section on colour therapy.)