See ((Caloric restriction)).
See ((Intermittent fasting)).

Fasting, the practice of voluntarily abstaining from food and nonwater beverages.

Fasting is, an effective nonpharmacologic strategy for counteracting cardiovascular disease, cancer, diabetes and diminishing cognition.

The willing abstinence or reduction from some or all food, drink, or both, for a period of time.

An absolute fast or dry fasting is normally defined as abstinence from all food and liquid for a defined period, usually 24 hours, or a number of days.

Water fasting refers to abstinence from all food and drink except water, but black coffee and tea may be consumed.

Other types of fasts may be partially restrictive, limiting only particular foods or substances, or be intermittent.

Physiologically, refers to the metabolic status of a person who has not eaten overnight, or to the metabolic state achieved after complete digestion and absorption of a meal.

A person is assumed to be fasting once 8–12 hours have elapsed since the last meal.

Metabolic changes of the fasting state begin typically 3–5 hours after eating, after absorption of a meal.

A diagnostic fast refers to prolonged fasting conducted to facilitate the investigation of a health complication, usually hypoglycemia, as part of a medical procedure or a check-up, and may also be part of a religious ritual.

Fasting prior to surgery or other procedures that require general anesthesia because of the risk of pulmonary aspiration of gastric contents after induction of anesthesia is routine.

Chronic fasting is not recommended for people with cancer at risk for weight loss or a suppressed immune system.

A study showed fasting improved alertness, mood, and subjective feelings of well-being, possibly improving overall symptoms of depression.

Fasting for periods shorter than 24 hours have been shown to be effective for weight loss in obese and healthy adults and to maintain lean body mass,

Often used as a tool to make a political statement, to protest, or to bring awareness to a cause.

Commonly used in religious practices and observances of many religions.

Fasting is the most widely adopted diet in those under age 34 in the United States.

The most popular fasting regimen is the 5:2 diet, in which participants restrict themselves to approximately 500-600 calories 2 days a week but eat as they normally would for the remaining 5 days.

Other regimens include time-restricted feeding, alternate-day fasting, and periodic fasting by abstaining from food and energy-containing beverages for continuous days, sometimes stretching out to 3 weeks.

Clinical evidence is strongest for the periodic fasting and fasting-mimicking diets used to treat specific problems, including obesity, high cholesterol, high blood pressure, inflammation, high triglycerides, and high fasting glucose/metabolic syndrome.

The major advantage of a periodic fasting or fasting-mimicking diet is that it only needs to be done for most people three to four times per year for 5 days.

With a fasting state, depletion of the stores of glucose in the liver occurs and converts it to fat-derived ketone bodies.

The liver converts fatty acids to ketone bodies, which provide a major source of energy for many tissues, especially the brain during the fasting.

In the fed state ketone blood levels are low, and they rise within 8-12 hours after the onset of fasting and reach levels as high as 2-5 mM by 24 hours.

Depending on your expenditure of energy during the fasting period, you can enter a ketogenic state within hours.

Fasting for durations of a few days increases metabolism.

Fasting regimens produce decreases in glucoregulatory markers, lipids, inflammatory markers, and weight.

The recommendation that we eat three meals a day with some snacking on top is mainly based on studies of diabetics, but it intermittent fasting actually improves glucose regulation.

The epidemic of obesity has occurred occurred in the past 40 years with the eating pattern of three meals a day plus snacks.

Fasting has the ability to enhance cognition and brain function.

Fasting-related ketogenic states lead to cellular and molecular adaptions in the brain resisting to stress, injury, and disease.

Ketones are an exceptional energy source for the brain, more so than the fluctuations of glucose.

Ketone bodies produced during fasting have profound effects on systemic metabolism, and also stimulate the gene for brain-derived neurotrophic factor with implications for brain health and psychiatric and neurodegenerative disorders.

Studies indicate that the benefits of intermittent fasting are dissociated from its effects on weight loss and the benefits include improvements in glucose regulation, blood pressure, heart rate, endurance training and abdominal fat loss.

Longer nighttime fasting duration is significantly associated with improved glycemic regulation, and thereby reduces risk for breast cancer.

In a study of 2400 patients who were in remission from early-stage breast cancer: those who self-reported nightly fasting of less than 13 hours, had a statistically significant 36% increase of the risk for breast cancer recurrence compared with those whose nightly fasting lasted more than 13 hours.

Nighttime eating negative effects, may be due to the fact insulin works well in the morning and early afternoon, but in the evening it begins to be counteracted by melatonin and growth hormone.

The three most widely studied intermittent fasting regimens or alternate-day fasting, 5:2 intermittent fasting, that is fasting two days a week, and daily time-restricted feeding.

Markedly reduced caloric intake diet on day one or more each week, that is a reduction to 500-700 cal per day, results in elevated levels of ketone bodies on those days.

With metabolic switch from use of glucose as a fuel, the use of fatty acids and ketone bodies result in reduced respiratory-exchange ratio indicating a greater metabolic flexibility and efficiency of energy production from fatty acids and ketone bodies.

Ketone bodies are fuel used during periods of fasting, they are also potent signaling molecules with major effects on cell and organ function.

Leave a Reply

Your email address will not be published. Required fields are marked *