Health is our most precious asset. In maintaining or restoring physical and mental vitality, nutrition is of vital importance. As early as 400 BC, the Greek physician Hippocrates aptly formulated “Let your food be your remedy and let your remedy be your food.” The word diet comes from the Greek word díaita and was originally used in the sense of “way of life”. Today, diet is used to describe a short-term change in diet for weight loss or weight gain, but also a longer-term to permanent change in diet for supportive treatment of a disease (dietetics).
Reduction diets
With over 500 variants, there is an unmanageable range of reduction diets. However, the nutritional assessment of these must be very differentiated in detail, since the justifications range from scientifically sound to justifiable to nonsensical or even dangerous. The main goal of any serious reduction diet must be the long-term change in dietary behavior. To minimize the risk of weight cycling, weight loss should not exceed 0.5 kg per week on average. Other basic rules of recommended reduction diets for permanent reduction of increased body weight are:
- Formulation of the desired weight as a goal
- Learning the enjoyable and anxiety-free approach to food.
- Calorie intake according to basic needs (at least 1,200 kcal/d).
- Energy-reduced, low-fat, carbohydrate and fiber-rich diet.
- Protein intake in sufficient quantity (0.8 g/kg bw/d) and quality.
- Fat content of the diet of about 30% energy and PS ratio: > 1 (= limit saturated fatty acids in favor of monounsaturated and polyunsaturated fatty acids).
- Carbohydrate content of the diet of more than 50% energy.
- Supply of supplements (dietary supplements) to meet the vitamin and mineral needs.
- Sufficient fluid intake (about 45 ml/kg bw / d).
- No or only a little alcohol
- Keeping food logs to record eating habits.
- Acquisition of nutrition knowledge
- Regular physical activity.
Reduction diets can be divided into fasting diets or extremely low-calorie diets, energy-reduced mixed diets, diets with extreme nutrient ratios, low glycemic index diets, flash diets, and psycho diets. In addition, there are various body weight loss programs that include elements other than diet, such as exercise and behavioral therapy. Alternative diets, such as Hay’s Food Combining Diet and Ayurvedic diet are also used for weight loss.
Fasting cures
The term fasting includes traditional total fasting (full fasting) as well as the worldview healing cures. As motivation for fasting weight loss, but also “detoxification of the body” are in the foreground. The partly propagated opinion that by means of chamfering cures many civilization diseases can be healed, is not scientifically justified. Examples of fasting cures are total fasting (full fasting), juice fasting/healing fasting according to Buchinger and the Schroth cure.
Energy-reduced mixed food diets
Energy-reduced mixed food diets are based predominantly on secured nutritional-physiological realizations. They are mainly based on a reduction of fat and thus energy intake. Since their nutrient ratio is mostly balanced, they can usually be practiced over a longer period of time. Examples of energy-reduced mixed diets are the Brigitte diet, Pfunds-Kur 2000, FdH (Friss die Hälfte) and Fit for Fun.
High-carbohydrate diets
High-carbohydrate diets are often associated with a high intake of fiber, vitamins, minerals, and phytochemicals. They also have a good satiety effect. However, the extreme food composition often leads to premature discontinuation of the diet, so that long-term success is rarely achieved. Examples of high-carbohydrate diets include the F-plan diet, the potato diet, and macrobiotic diets as a form of dieting.
High protein diet
In high protein diets, up to 50% of dietary energy comes from protein, whereas fat and carbohydrate content is usually low.Due to the good saturation effect, weight reduction can be achieved. However, the strong shift of the main nutrients can lead to ketonemia and uremia as well as stress the kidneys. Examples of high-protein diets include the Hollywood Diet, Mayo Diet, and Manager’s Diet.
Low-carbohydrate diets (low-carb diets)
Low-carbohydrate diets are high in fat and protein and unlimited in energy. The limited food choices usually lead to taste fatigue in a relatively short period of time. Because of the often extreme nutrient ratios, these diets can be harmful to health in the long run. Examples of low-carbohydrate diets are the Atkins diet and the South Beach diet.
Low-glycemic index diets
Low-glycemic index carbohydrate foods supposedly support weight loss through their good satiety effects as well as by increasing lipolysis, due to low postprandial insulin secretion. However, the scientific data regarding these assumptions has not been consistent to date. Examples of low glycemic index diets include the Montignax method and the LOGI method according to Worms.
Flash diets (fashion crash diets)
The founders of flash diets, which are often named after the preferred food, usually promise high weight losses within a few days. If used for a longer period of time, there is a risk of insufficient supply of vitamins, minerals and trace elements. In addition, the motivation often decreases quickly due to the monotony in the food selection. Examples of flash diets are the cabbage soup diet, pineapple diet and apple diet.
Psycho diets
Many psycho diets focus on exploring the psychological or mental causes of increased body weight. In addition, mental exercises are used to influence the perception of one’s own body and to increase the stimulus threshold for certain foods such as fast food, sweets or desserts. However, nutritional concepts are often completely absent. Examples of psycho diets are “mental slimming” and “think yourself slim”.
Weight loss programs
The primary goals of weight loss programs are to permanently change eating habits and to eat according to needs. The programs are usually based on a holistic approach and include physical activity and behavioral training in addition to nutrition. Examples of weight loss programs include “Weight Watchers” and “Almased.”
Alternative diets
The alternative forms of nutrition are mainly practiced on a long-term basis, although some of them fundamentally deviate from the diet that is common in our country today. The origin of some alternative forms of nutrition is already in ancient times. Examples are vegetarianism, macrobiotics and Ayurvedic nutrition. Other alternative diets, such as Hay’s food combining diet, the Waerland diet and anthroposophical nutrition, arose from the life reform movement in Central Europe and the USA, which peaked around 1900. In the second half of the 20th century, alternative diets were developed, such as the whole food diet, the Evers diet, the Schnitzer diet, the raw food diet or “Fit for Life“. It is noticeable that the various alternative diets have relatively many things in common, such as:
- Preference for plant-based foods
- Preference for food from organic farming
- Preference for regional and seasonal foods
- Rejection of highly processed foods
- Preference for gentle food preparation methods
- Holistic view.
However, a blanket nutritional assessment of alternative diets is not possible, because as with all diets, the practical design can vary greatly. A questioning of the alternative forms of nutrition must take place with regard to:
- The satisfaction of needs,
- The composition of the diet compared to the nutrient recommendations of professional societies,
- possible side effects and risks and
- The promises of a cure.
The alternative diets often require more detailed knowledge of nutrition, as deficiencies can occur if not used properly. For vulnerable groups, such as children, adolescents, pregnant women, nursing mothers, the elderly and the sick, some alternative diets are not recommended or only limited.The statements of the alternative nourishing forms reach, as with the reduction diets, from scientifically founded over justifiable up to nonsensical or even dangerous. The alternative diets can be divided into the predominantly health-oriented alternative diets and the predominantly ideology-oriented alternative diets.
Predominantly health-oriented alternative diets
The predominantly health-oriented diets claim to contribute in a special way to the preservation or restoration of health and protection against certain or all diseases. Examples of these alternative diets include Fit for Life, Hay’s Food Combining Diet, Raw Food Nutrition, and Evers Diet.
Predominantly ideologically oriented alternative diets
The nutritional recommendations of the predominantly ideologically oriented alternative forms of nutrition are sometimes very complex, whereby nutrition is to be understood as part of an overall philosophy. The goals of such forms of nutrition are, for example, personal consciousness development, preservation of the environment or social justice. The health and ideological origins cannot always be clearly separated. Examples of these alternative diets include macrobiotic nutrition, Ayurvedic nutrition, anthroposophic nutrition, and traditional Chinese medicine (TCM) nutrition.
Diets for the treatment of diseases
Many diseases can be positively influenced by adequate nutrition. Nutritional medicine attempts to use current scientific knowledge about the physiology and pathophysiology of human nutrition to prevent and treat diseases. Examples of diseases for which a specific diet reduces the risk of disease or promotes healing include. Obesity, diabetes mellitus, hypertension (high blood pressure), hyperlipidemias and dyslipidemias (disorders of lipid metabolism), cardiovascular disease, cancer, iodine-deficient goiter, dental caries, osteoporosis (bone loss), rheumatoid arthritis, hyperuricemia and gout, kidney stones, gallstones, atopic dermatitis, food intolerances, gastrointestinal (gastrointestinal) disease, eating disorders.