Very simply, a whole food diet consists entirely of whole foods ("real food") and traditionally-made foods, and entirely avoids industrially-made processed food.
There are many different approaches--that is, many different diets with different food philosophies.
I think every approach has value. You can learn from radically different diets, finding healthy whole foods and healthy preparation techniques that you wouldn't otherwise be aware of--foods and techniques missing from the Standard American Diet.
The differences in the diets often stem from the following controversies: whether to include meat and other foods that come from animals; how much fat to eat; what kinds of carbohydrates to eat and in what quantity; whether grains are harmful or essential; whether food should be cooked or raw; and which superfoods are indispensable.
This site favors the Weston Price diet as promoted by the Weston A. Price Foundation. I believe its principles are the most likely to benefit the most people. Its sole drawback is that anyone with celiac or other food intolerances will need to adjust its principles individually.
The diet is based entirely on eating for high nutritional content. It prohibits processed foods and any foods not prepared in a traditional manner.
It includes high-nutrient animal foods, encourages healthy fat consumption, urges special preparation and cooking of grains and beans, and suggests many valuable superfoods. Read more here.
In the 1930s, Weston Price studied traditional diets around the world. A traditional diet is one that's been developed over centuries by people who never had access to modern food. It could be the diet of tribal people, of hunter-gatherers, or of farming and fishing villages.
Price found that traditional people who ate traditional diets were in excellent health! They did not have the "diseases of Western civilization" nor the diseases of poverty.
The key findings: the healthiest traditional diets included no processed foods, but did contain from four to fifty times more vitamins and minerals than the American diet does. All of the healthiest diets included nutrients from some animal foods.
His book Nutrition and Physical Degeneration describes his discoveries. You can read my summary and review here.
Several whole food diets use fermented foods (also known as cultured foods) to heal the gut lining, solve persistent digestive problems, and improve health conditions.
Besides using fresh, whole foods, these diets are sugar-free and free of processed foods.
The diets typically restrict carbohydrates, especially during initial phases. They use special cultured foods that may include raw sauerkraut and other raw fermented vegetables; yogurt and kefir made by fermenting milk, coconut milk, or coconut water; and others.
Three well-known cultured foods diets with different particulars are: the Specific Carbohydrate Diet (SCD); the Body Ecology Diet; and the GAPS (Gut and Psychology Syndrome) Diet.
The idea behind the Specific Carbohydrate Diet is to heal the gut by avoiding processed food, refined sugar, and complex carbohydrates. Complex carbohydrates, which include grains and starchy vegetables, can be difficult to digest and consequently feed bad gut bacteria. Homemade yogurt plays an important role in the diet. Over time, with the diet, bad bacteria die and gut integrity is restored. Read more here.
The Body Ecology Diet heals the gut by avoiding gluten, casein (a protein found in dairy foods), processed food, and refined sugar. It reduces carbohydrates. The healing agents are cultured foods and healthy fats. Read more here.
The GAPS Diet is an intense program to heal neurological conditions and extremely damaged guts. The concept is that the gut is so damaged that toxins from bad gut bacteria are affecting the brain and nervous system.
It's based on the SCD Diet in restricting certain types of carbohydrates (and of course prohibiting processed food and refined sugar), but it is a long-term step-by-step program. It heals with homemade broths and soups, fermented foods, and healthy meats, eggs, and fats.
No one has ever shown that grains are nutritionally necessary. Nothing in Weston Price's discoveries suggests that grains are necessary to health.
There are, however, many people (most unaware of it) who have health problems due to modern grains. Grain-free diets are a recent acknowledgement of this.
As this relates to whole food diets: Many people of course have undertaken gluten-free diets or low-carbohydrate diets without using exclusively whole foods. But the diets work much better for their purposes when they are whole food diets.
Gluten-Free Diet: Requires absolute avoidance of wheat, barley, rye, commercial oats, and any ingredient or additive derived from those grains. It is used for the treatment of celiac disease, gluten intolerance, autism, and autoimmune diseases.
Low Carb High Fat Diet: These diets prohibit or restrict grains and sometimes other carbohydrates. The Paleo diet is a high-protein, moderate-fat, no grains diet; Primal Blueprint is a high-protein, high-fat, no-grains diet.
Some whole food diets, for medical or philosophical reasons, avoid meat and other food sourced from animals: meat, fish, milk, foods made from milk such as cheese, eggs.
Of course, no diet has ever included, nor could include, every food on earth. Weston Price's work showed how the seemingly strange or restricted diets of traditional people were, no matter how different from each other, all high in certain nutrients.
I think the issue should be not whether a diet is restrictive but whether it includes those nutritional factors that Price showed are necessary. Therefore, in good conscience I couldn't recommend diets that I know lack elements he identified--nutrients sourced from animals.
However, there clearly are people who thrive on these usually vegan diets. There are also common disease conditions that can respond to them. There are often special ways to maximize the nutrients in vegan diets. And sometimes it may be better to eat no animal foods than low-quality animal foods that are filled with toxins and hormones.
It is possible but not typical to include Weston Price principles in these other whole food diets. But, they represent a variety of healing traditions and they offer many creative whole food ideas. Again, I believe that everyone can definitely benefit from the foods and principles in these very different diets. I've been influenced by both raw food and macrobiotics.
Raw Food Diets are typically vegan (no animal foods) and low fat, but not necessarily, as the only common factor is the prohibition of cooking. If used, grains would be sprouted and sun dried, never cooked. There are many raw superfoods, and many raw high-enzyme foods. It's also possible to eat (say) 80% raw, or some other percentage of your choice.
Macrobiotics is typically vegan but may include fish; it is a cooked-food, low-fat diet. More than half the diet consists of whole grains. Most foods, including fruit and vegetables, are cooked. There are many special and traditional Asian superfoods.
Whole foods arrive at your kitchen as they were made by nature. They include: fresh fruits and vegetables; whole grains; legumes; nuts and seeds; unprocessed meat, poultry, organ meat, and fish; eggs; raw milk. You can think of them as "real food."
Traditionally-made foods are made at home, by small-scale artisans, or other production using traditional methods. These can include specially-made butter, cheese, yogurt, expeller-pressed oils, whole-grain bread, unrefined salt, and others. They are not typically found in supermarkets.
In contrast, processed food is manufactured, in factories, using high (industrial) temperatures, chemicals, and additives. Food is processed in this way to give it a lengthy "shelf life."
The following are principles common to most diets:
Nutrient-dense food
Food with a high concentration of vitamins and minerals is nutrient-dense. The ultimate nutrient-dense foods are called superfoods; the ultimate low-nutrient foods are junk foods.
Superfoods
Foods with a super concentration of nutrition are often called superfoods. Frequently, they contain special nutrients with unique benefits that are hard to obtain elsewhere.
High-enzyme foods
Enzymes are proteins that carry out all the functions of the body. Our bodies make these enzymes, but all wild animal diets and all healthy human diets include enzymes in food. More information is in the classic book Enzyme Nutrition.
Special preparation methods
Traditional food preparation often increases the nutrient content of foods (and eliminates anti-nutrients). There is more information--why and how-to--in the cookbook Nourishing Traditions.
Antioxidants
Antioxidants are nutrients that prevent cellular damage. Aging, disease, toxins, and even the normal functions of the body cause cellular (and tissue) damage through the process of "oxidative injury" or "free radical damage." Antioxidants can be vitamins, minerals, thiols, flavonoids, or enzymes, all from food.
Phytochemicals
Fruits, vegetables, beans, and grains contain thousands of phytochemicals ("plant chemicals") that create the color, taste, and other properties of plant foods. Many of these pigments, flavonoids, and other phytochemicals are extremely beneficial. The book The Color Code tells how to crack the "code" of the healthful pigments of fruits and vegetables.
Fat-soluble vitamins
These are vitamins A, D, and K2, primarily from animal products such as seafood, organ meats, eggs, and dairy products. They need dietary fat to be absorbed.