Diet therapy, a biologically based practice, uses specialized dietary regimens (such as macrobiotic, Paleo, Mediterranean, and low-carbohydrate diets) to
Treat or prevent a specific disease (such as cancer or cardiovascular disorders)
Generally promote wellness
Detoxify the body (by neutralizing or eliminating toxins from the body)
Some diets (such as the Mediterranean diet) are widely accepted and encouraged in traditional Western medicine.
When beginning a therapeutic diet that involves a dramatically different way of eating, people should ask an expert to advise them so that they can avoid nutritional deficiencies. Dietary science and understanding is constantly evolving and should be revisited frequently with a healthcare or nutrition professional.
Intermittent Fasting
Intermittent fasting has various forms, including restricting eating to certain times of the day (usually less than 10 hours, often called time-restricted feeding) or not eating for a day or longer (eg, alternate-day fasting). Intermittent fasting causes a switch from using glucose stored in the liver to ketones stored in fat. It has been shown to have favorable metabolic effects (eg, increased insulin sensitivity, possibly increased lifespan) in animal studies. Health benefits in humans, include reduced body weight and waist circumference compared to no dietary intervention although long-term efficacy is uncertain. Whether intermittent fasting is more effective than general caloric restriction is also a question. One concern with weight loss by fasting is concurrent loss of lean body mass while losing fat mass; although loss of fat mass may contribute to metabolic benefits, this may be offset by the detrimental health effects of losing muscle mass.
Keto Diet
The keto diet, similar to the Paleo diet, contains very high fat-containing foods and very low amounts of carbohydrates. The diet aims to induce ketosis, a state in which fat is burned as the source of energy, resulting in weight loss. The keto diet has been shown to suppress hunger, resulting in decreased weight, waist circumference, triglycerides, hemoglobin A1C, and blood glucose.
Typical foods in the keto diet include avocados, oils, nuts, fatty fish, eggs, beef, chicken, vegetables, cheese, butter, and cream. The restricted diet is not always palatable, and adherence is a problem.
Risks include gastrointestinal symptoms such as constipation, nausea, vomiting, and diarrhea. Individuals may experience the so called "keto flu," which is characterized by headache, fatigue, irritability, difficulty sleeping, and nausea. Other risks include biochemical imbalance (elevated lipid, calcium and protein levels), kidney stones, liver damage, and anemia.
Macrobiotic Diet
The macrobiotic diet consists of largely vegetables, whole grains, fruits, and cereals. Although some people following a macrobiotic diet report improvements in cancer and its symptoms, well-designed research studies have not confirmed this.
Risks of a macrobiotic diet include unintended weight loss and sometimes inadequate intake of certain nutrients.
Ornish Diet
This very low-fat vegetarian diet aims to help reverse arterial blockages that cause coronary artery disease and may help prevent or slow the progression of prostate and other cancers. It focuses on plant-based foods and avoidance of fat, refined carbohydrates, and animal protein. As a component of an intensive lifestyle program for participants with symptomatic coronary artery disease, the Ornish diet is effective. However, it is not clear what benefits result from the specific food restrictions of the diet. Similar benefits may result from other diets that limit less healthful fats and refined carbohydrates but do not limit more healthful fats (eg, olive oil).
Paleo Diet
The Paleo diet consists of types of food allegedly consumed in the distant past during the Paleolithic (Stone Age) era, when food was hunted or gathered. That is, it consists of foods made from animals and wild plants. Thus, the diet results in the following:
Eating more protein
Eating fewer carbohydrates and eating mainly nonstarchy fresh fruits and vegetables
Consuming more fiber
Often eating more fat, mainly monounsaturated and polyunsaturated fats
Foods thought not to be available during the Paleolithic era (such as dairy products, grains, legumes, processed oils, refined sugar, salt, and coffee) are avoided. Proponents claim that people cannot process (metabolize) many of these foods. However, knowledge of what was eaten in the Paleolithic era is limited, and some evidence suggests that in the Paleolithic era, the diet was not as limited as the modern Paleo diet.
Proponents of the Paleo diet claim that it reduces the risk of coronary artery disease, type 2 diabetes, and many chronic conditions. They also claim it promotes weight loss, improves athletic performance, enhances sleep, and improves mental function. However, evidence that this diet has any of these effects remains inconsistent.
Risks of the Paleo diet include inadequate intake of certain nutrients (due to decreased consumption of whole grains and dairy products) and possibly an increased risk of coronary artery disease (due to increased consumption of fat and protein).
