## What is the purpose? Intermittent fasting divides the day into periods when you eat (almost anything you want), and when you don't eat at all. "Hunger" period affects the work of internal organs, so before you decide to resort to this system of dieting, it is better to make sure that the state of the body allows it. ## What should be checked before starting? __Liver__. If the liver is healthy, interval fasting will not affect its work, and if it does, then it is for the better. However, when there are problems with the liver this diet can lead to the development of fatty hepatosis as well as problems with the excretion of bile. Therefore, if there are stones in the bile ducts, it is necessary to consult with a gastroenterologist before starting interval fasting. You can make sure you are not harming your liver by checking your ALT and AST liver enzyme levels. __Kidneys.__ Intermittent fasting can accelerate the stone formation and lead to the deposition of uric acid stones. Additionally, kidneys filter urine constantly, so remember to drink water during the "starvation window.". If you have chronic kidney disease, beginning intermittent fasting will require the approval of a nephrologist or therapist, who will check urea and creatinine levels to make sure it is safe for you to begin this diet. __Pancreas.__ During fasting the body's sensitivity to insulin increases, which can cause many deadly diseases. By taking insulin resistance tests before intermittent fasting and then repeating them after the time has passed, you and your doctor will see increases in your health. Intermittent fasting reduces the risk of developing type 2 diabetes, metabolic syndrome, helps keep blood pressure normal, activates autophagy processes, and therefore prolongs life. It may be necessary to take glucose on an empty stomach as well as fasting insulin. Additionally, NOMA and Caro indices will be calculated by the lab. __Thyroid.__ Intermittent fasting leads to activation of the thyroid gland as the body "takes out" energy from reserves, which causes weight loss. It is sufficient to have a screening test to determine the level of the thyroid gland before and after the beginning of this diet. __Lipid profile.__ During interval fasting, it is important not to overeat at the "meal window," but to maintain healthy eating habits — for example, in the form of a Mediterranean diet, with moderate caloric restriction to 1800/2000 calories/day for women and men respectively. The mistake many people make is that during the "nutritious" period a person tries to eat more nourishing, including fatty foods. Therefore, it is important to control cholesterol, LDL, HDL, and triglyceride levels. > If you do intermittent fasting correctly, the level of "bad" and total cholesterol and triglycerides, on the contrary, will decrease, while the level of "good" cholesterol, which prevents the formation of atherosclerotic plaques, will normalize. ## Who should avoid intermittent fasting? - People with a predisposition to cholelithiasis - People who have any pathology of the gastrointestinal tract - People with kidney disease (glomerulonephritis, pyelonephritis, urolithiasis) - Pregnant and lactating women - Minors - People with anorexia or bulimia - Patients with type 1 diabetes __Note:__ with caution and only with the permission of the doctor (and the reason for this caution lies in the type of antidiabetic therapy), this method can be used with type 2 diabetes mellitus with excessive weight/obesity.