While milder than other types of fasting, partial fasting does offer the same benefits of healing and cleansing of the body. The speed at which detox occurs can be slower, but that also means it will be more comfortable.
There are lots of terms used in relation to partial fasting: selective fasting, modified fasting, fasting diet, cleansing diet, single food fast, one-food diet, and mono-diet are some you'll run into.
Since some of the more intense fasting methods, like water, aren't appropriate for all people, at all times (read the Who Can Fast page for more information), partial fasting may sometimes be the better choice. The intensity of a partial fast will vary according to which type you use. They can be just as intense as liquid fasting or as mild as eating a regular diet.
As opposed to dry fasting and liquid fasting, partial fasting includes some solid food--from a very little to quite a lot, as it's not the amount of food but the exclusion or limitation of certain foods that makes it a partial fast. For instance, the Daniel Fast (see below) is actually a well-rounded diet encompassing complete and normal nutritional levels. On the other hand, a mono-diet apple fast consists of just a few apples per day.
Calling the eating of normal quantities of solid foodstuffs a "fast" is a bit of a mis-use of the original term; regimens like the Daniel Fast would more accurately be called "diets". But modern language has developed the term "partial fasting" or "selective fasting" to refer to these regimens.
Even a partial fast with normal nutritional levels, such as the Daniel Fast or a cleansing diet, can be very cleansing and detoxing when it eliminates chemicals, processed foods, and "dead" foods, and replaces them with nature's living foods.
A mono-diet, eating just one food for a length of time, has the additional benefit of providing rest to the digestive organs, same as a more traditional liquid/water fast does, only to a slightly lesser extent. On a mono-diet, the intestinal system only needs to provide a limited number of enzymes to break down the food, therefore the most easily digested foods make the best candidates.
That's why fruit and rice have been used for this purpose for centuries. As long as "feasting" doesn't occur and quantities are kept to a minimum, for example, 3-4 apples per day or 3 cups of cooked rice per day, the digestive system is afforded a rest and healing and rejuvenation can occur.