Nutritional therapy for overweight
In the non-pharmacological treatment of obesity, a moderate, stepwise weight loss method is used in most cases, with three main stages.
The first stage, which lasts from 1 to 6 months of treatment, involves weight loss of about 10 percent of the initial weight.
From 7 to 12 months, the weight should be maintained at a level between 5 and 10% below the initial level. At this stage, no further weight loss should be attempted due to a decrease in basal metabolism, which occurs after 6 months of obesity treatment. Attempting to force weight loss at this stage causes such a significant reduction in basal metabolism that patients relapse into obesity. Basal metabolism is not stabilised at a new level until 1 year after the start of treatment.
Subsequently, a third phase of weight loss is initiated, in which further weight loss is achieved.
Restricted caloric intake has been shown to prolong life by at least 30% to 40% by methylation of the genome.
Low-calorie diet
The technique of moderate stepwise weight loss involves following a low calorie diet (LDC), where the daily caloric intake for women is 1200-1400 kcal and for men 1400-1600 kcal.
In patients on a low-calorie diet, the amount of fat consumed in food should not exceed 29% of the daily calorie intake. The fat intake should be 30-50% polyunsaturated fatty acids. The amount of saturated fatty acids is limited – their energy value should not exceed 10% of the daily calorie intake. Sources of animal fats can be lean fish, poultry (without skin), occasionally the use of lean beef tenderloin. The cholesterol content in food should not exceed 300 mg per day.
The energy value of protein in a low-calorie diet is about 15% of the daily caloric intake. It is recommended that 1/3 of the daily amount of protein be consumed in the form of soy products. Carbohydrates account for 50-60% of the daily kilocalories consumed.
Carbohydrates should be represented mainly by fibre (vegetables, fruit, unsweetened berries) and soluble dietary fibres (wholemeal bread, bran, whole oats and barley, pulses). Limited use of pasta made from durum wheat is allowed.
For calcium supplementation, 0.5-1% fat milk or kefir and completely non-fat cottage cheese should be added to the diet. Table salt is limited to 4.5 g per day. The amount of fluid consumed daily is 1.5-2 litres. Green tea is recommended, containing significant amounts of catechins, which increase basal metabolism and stimulate postprandial thermogenesis. Consumption of three servings of green tea per day before the main meals increases energy expenditure by 80 kcal per day. Alcohol consumption should be restricted where possible. It is advisable to take daily multivitamins. A low-calorie diet is good for life.
A very low-calorie diet
There is also the rapid weight loss method, which reduces body weight by 15-20% in 3 months. A very low-calorie diet (VLCD) is used as part of this methodology.
The duration of the ONCD should not exceed 16 weeks. The daily caloric intake of the ONCD does not exceed 800 kcal.
To prevent cachexia, at least 1 g of complete protein per 1 kg body weight per day should be consumed in ONDCP. A minimum of 100 g of carbohydrate per day should be consumed to prevent ketoacidosis. The dietary intake for CNPD is enriched not only with calcium, but also with potassium and magnesium.
The daily intake of good-quality multivitamins is mandatory. A very low-calorie diet leads to a rapid and pronounced decrease in basal metabolism, which can lead to a relapse into obesity.
Contraindications
Note that a very low calorie diet is contraindicated in kidney disease, liver disease, cholelithiasis, gallstone disease, bronchial asthma, cancer, type 1 diabetes, heart rhythm disturbances, in the recovery period of stroke or myocardial infarction, infectious diseases, alcoholism, drug dependence. It should not be prescribed for children and patients over 65 years of age.
Other weight loss diets
There are also other diet therapy recommendations for obesity: the Atkins diet, the protein diet (Zone), the Ornish vegetarian diet and even a diet that includes the patient’s diet according to their blood type. The disadvantages of all these diet therapies are that they have not been tested in multicentre clinical trials and they have had significant side effects. The effectiveness of different types of nutritional therapy for obesity has been evaluated by the National Registry of Body Mass Correction (USA). They analysed 3000 cases of successful non-medicinal treatment of obesity. It was found that 98.1% of cases were successful in treating obesity in patients following the NCD, 0.9% in patients following the Atkins diet, and 1% in all other dietary treatments.