Definition of Fruitarianism:
Fruitarianism is defined as a diet that is predominantly raw fruit (75+% by weight), with the remainder of the diet being composed of raw vegetarian (raw vegan) foods. Here fruit has the common definition, i.e., the reproductive parts of a vine, bush, or tree, that includes a juicy pulp. The common definition is used here rather than the botanical, as the botanical definition is too broad, e.g., grain is considered a fruit under the botanical definition (but not the common definition).
Summary Statement on Fruitarianism:
Fruitarianism is possible according to idealistic dietary theory, but it can be very difficult in practice. The diet has many pitfalls that can cause serious problems for the would-be fruitarian. Fruitarianism portrays fruit as the ideal natural food, yet modern fruit is the product of generations (in some cases, thousands of years) of human-directed plant breeding. In short, modern fruit has been bred for a high sugar content, and is greatly over-rated as a food.
Very few people claim to succeed on the fruitarian diet, in the long term. Additionally, the high incidence of binge eating, "cheating," and backsliding in raw veganism raises serious questions regarding the credibility of the few claims of long-term success. Here, one should apply common sense: there are very few long-term success stories, and even fewer credible success stories for fruitarianism. Does that suggest that it is the "ideal, natural" diet for everyone, as its advocates claim, or a fringe diet that appeals primarily to idealists? This question deserves serious consideration, particularly if you are considering adopting the diet, as you may be putting your health at risk.
Fruitarianism: Pro
Fruit is widely regarded as the best tasting raw vegetarian food, and eating fruit is certainly pleasant--after all, we (nearly) all like sugar!
It is said to be a "cleansing diet," and may be helpful (in the short run) as a therapeutic diet. (This applies to other raw food diets as well, including non-vegetarian raw diets.)
Fruit, if it is grown locally and not shipped, refrigerated, fumigated, subjected to heat/cold treatment to kill fruit flies, etc., might be considered to be a "low violence" food. However, shipping fruit, refrigerating it, etc. all involve some level of violence to the environment. Fruit subjected to such processing cannot be considered a "low violence" food. In other words, to use the New Age terminology, most fruit is neither "cruelty-free" nor "karma-free."
Promotes weight loss and gives you a light body.
Fruitarianism alters your mental state, promoting a light and airy mental feeling that some find pleasant. Some interpret this as a "spiritual" feeling.
In the short run, it can promote physical health, i.e., you appear to be immune to many illnesses, and injuries may heal quickly. This, combined with the "light" mental effect, may make it appear that you are somehow experiencing a "higher" state of living.
Your respiratory system may function better on a fruitarian diet than on other (cooked) diets, though only slightly better (or the same) as other raw food diets.
It may sharpen your senses to an extraordinary degree, specifically the senses of taste and smell. Your sense of smell may get so sharp that it is (emotionally) painful to sit in the same room with someone who eats a lot of garlic, or who smells of tobacco.
It may reduce the amount of water you need to drink, as fruit has a high water content.
Fruitarianism: Con
Modern fruit is expensive, and often lacking in freshness and/or quality as a result of shipping, refrigeration, fumigation, and other post-harvest processing. The importance of year-round access to good quality local fruit may limit the applicability of fruitarianism.
Strict fruitarians usually experience severe weight loss, with weight stabilizing at levels associated with anorexia nervosa or starvation. It is extremely difficult to gain weight on a fruit diet, even if you overeat avocados.
Advocates of fruitarianism claim that anyone can succeed on their ideal, natural fruitarian diet if they have faith or positive thinking. This is an obvious contradiction: does the cow need faith to succeed on diet of grass? Does the lion need positive thinking to succeed on a diet of zebra, antelope, and wildebeest meat? Of course not! If you need faith to succeed, it is probably not the "ideal, natural" diet as claimed by the advocates.
The diet is extremely difficult, as most people find that a fruit diet is neither physically nor psychologically satisfying. Hunger and cravings are frequent, and backsliding, cheating, and binge eating are very common.
Fruitarians often display food-obsessive behavior. Take two pieces of bread, give one to an anoretic [an individual suffering from anorexia nervosa; see note (2) at end], and another to a fruitarian. The anoretic thinks, "I can't eat this bread, it will make me fat!". The fruitarian may think in a similar matter: "I can't eat this bread!" - with the reason(s) cited being one or more of the following delusions:
The bread is cooked, hence toxic.
The bread will produce mucus, which is the cause of all disease, and hence will make me "impure."
The bread contains protein (and/or starch), and all protein/starch is toxic and a horror.
Here the point is the obsessive attitude toward food and the pathological fear, that are common to both the anoretic and the fruitarian.
On fruitarian diets, it is very easy to overeat and to fall into the nasty trap of sugar addiction. Sugar is well known for its ability to promote food cravings, which often leads to binge eating and/or overeating.
Modern, cultivated fruit is very high in sugar, higher in sugar than most wild, uncultivated fruits. A diet of only fruit may provide excess sugar intake, resulting in diabetes-like symptoms:
sugar cravings,
excessive urination and thirst,
sugar highs/blues,
fatigue.
Excessive sugar, in the long run, may have a negative effect on the pancreas. Fruitarians would be well advised to daily eat some dark, bitter, leafy greens--according to several herbal health systems, bitter greens help regulate sugar metabolism and reduce sugar cravings.
Fruitarian diets are often very socially isolating. This can be very difficult for some people to handle: extroverts should not try to be fruitarians! The social isolation can promote a sense of psychological deprivation, which further encourages backsliding and binge eating. The social isolation and psychological deprivation can also warp your perception of eating; instead of eating being a nourishing, nurturing experience, it becomes an exercise in egoism (similar to the phony compassion/ego trap that many ethical vegans fall into). One may closely identify with the diet: it becomes a "badge" or "symbol" that defines your individuality--in other words, a projection of the ego, rather than a peaceful, nourishing experience.
Many fruitarians eventually give up the diet as it is too difficult to continue--the intense food obsessions, social isolation, psychological deprivation, frequent hunger--take their toll, with burnout the eventual result. It's interesting that some untreated anoretics also eventually recover from anorexia nervosa for the same reasons. In practice there is little difference in avoiding eating because you fear getting fat, and eating an inadequate (starvation) diet because of fear of cooked food, mucus or protein.
One must be very careful to practice fruitarianism with a positive attitude, lest it become a diet motivated by an obsessive fear of cooked food, mucus, or protein. When fruitarianism is characterized and motivated by obsessive fear, it becomes an actual eating disorder.
Fruitarians may experience a light, airy "mental" feeling that some compare to a minor drug high, and others mistake for some kind of spiritual feeling. However, the light feeling one gets from fruitarianism does not compare to, and is not the same as, the secure, peaceful, loving feelings that one gets from meditation or other genuine spiritual practices. I speak from direct personal experience on this point, having experienced both kinds of feelings. (Note: some anoretics report mental effects similar to those experienced by fruitarians; that is one reason anorexia nervosa is so hard to overcome.)
Furthermore, the light or euphoric mental feelings reported by some fruitarians (and those with anorexia nervosa) may be a symptom of zinc deficiency. Zinc supplements are sometimes used in therapy for anorexia nervosa. Similarly, the loss of libido reported by many fruitarians may be yet another symptom of a zinc deficiency (zinc is in short supply in most raw vegan and fruitarian diets).
Fruitarianism, especially the ~100% fruit version, is claimed to be a very "purifying" diet on the physical level. However, it is my observation/opinion that extensive physical "purification," without accompanying spiritual or ethical development, usually leads to mental and/or emotional problems. These mental or emotional problems can take many forms; a few examples from my personal experience are as follows.
A puritanical fruitarian who was obsessed with two things--food and his bowel movements--and who drank vinegar like it was water.
A fruitarian who left his wife, moved to South America and lived naked with his girlfriends on a mountain. The numerous fruitarian extremists who vigorously attack all diets other than raw vegan, and whose dialog is filled with egoism, anger, intense hatred, and other negativity. A pure body is irrelevant if your heart and mind are overflowing with the poisons of anger and negativity.