For example, studies have found that people who regularly fast more than 16 or 18 hours a day have a higher risk of gallstones. They're also more likely to need surgery to remove the gallbladder. Eating for 12 hours and then fasting for 12 hours is likely safe for most people, Longo explains.
The liver will use the last of its glycogen reserves around 18 to 24 hours of fasting. At this point, the body enters into a state called gluconeogenesis, marking the body's transition into fasting mode. With no carbohydrates coming in, the body creates its own glucose using mainly fat.
During a 23-hour fasting window, all the readily available glucose is used up. This leads your body to turn to a different source of energy—stored fat. The one-meal-a-day group also saw slightly greater weight and fat loss compared to the three-meals-per-day group.
Fasting 20 hours a day is safe. It gives your body time to go from the feeding-state to the repair-state. It's not good to eat all day. I would caution you on eating at 1 am. That seems really late, unless you have an unusual work schedule. You should get sleep. The body naturally wants to sleep at that time.
Longer periods without food, such as 24-, 36-, 48- and 72-hour fasting periods, are not necessarily better for you, and may be dangerous. Going too long without eating might actually encourage your body to start storing more fat in response to starvation.
Safety Concerns. For most people, there are no serious dangers involved in eating one meal a day, other than the discomforts of feeling hungry. That said, there are some risks for people with cardiovascular disease or diabetes. Eating one meal a day can increase your blood pressure and cholesterol.
For those aiming to lose belly fat, the 16/8 method is often recommended as the best intermittent fasting window to lose belly fat. By fasting for 16 hours and eating within an 8-hour window, you give your body enough time to burn stored fat while still allowing for a manageable eating period.
Various researchers have reported that fasting may lead to improvements in liver function, potentially indicating a reduction in liver fat accumulation or inflammation. Additionally, total cholesterol levels, which are known to be associated with NAFLD, may also improve during this fasting period.
Most people find the 16/8 method, which entails fasting every day for 14-16 hours and restricting your daily eating window to 8-10 hours, to be the most sustainable.
If you are fasting for weight loss or metabolic health, then coffee or even coffee with non-insulinogenic (insulin-spiking) additions like butter, coconut oil, or heavy cream should not break your fast. However, milk, flavored creamer, sugar, and many other sweeteners will break your fast, no matter your goals.
What is the most effective fasting time window? Fat burning typically begins after approximately 12 hours of fasting and escalates between 16 and 24 hours of fasting.
After fasting, your body needs gentle food options to ease back into digestion. Focus on hydrating, easy-to-digest foods — think light veggie soups, simple smoothies, or bland foods like rice or toast. Avoid foods that are high in fiber, fat, sugar, or spice.
The Warrior Diet is a relatively extreme form of intermittent fasting. It involves eating very little, usually just a few servings of raw fruit and vegetables, during a 20-hour fasting window, then eating one large meal at night. The eating window is usually only around 4 hours.
Intermittent Fasting Foods
You can eat mostly what you want on days when you don't fast. But to lose weight and get the nutrients you need, you should stick to healthy foods and limit treats such as desserts, alcohol, and processed foods. On fasting days, you'll eat very little food or none at all.
When you exercise in a fasted state your glycogen stores are already depleted. If your workout for the day involves heavy lifting, you can do so in a fasted state, but you should prioritize eating a meal directly following your workout.
Many medical experts agree that a one-day fast can feel great. But extending beyond three days can begin to cause harm, especially if you have other medical conditions, such as diabetes or heart disease. “A fast longer than a day or two can deplete vitamins, minerals and electrolytes,” Dr. Hopkins says.
The first starts as early as a skipped meal; the second comes with any prolonged period of fasting when the body relies upon stored fats for energy. The third, and often fatal, stage is when all stored fats have been depleted and the body turns to bone and muscle as sources of energy.
In 1965, Angus Barbieri from Scotland completed an incredible 392-day fast, consuming only vitamins, yeast, and zero-calorie beverages. He lost 276 pounds, reducing his weight from 456 to 180 pounds, and set a Guinness World Record for the longest recorded fast without solid food.
How much weight can I lose in 1 month by drinking hot water? There is no specific weight loss amount attributed solely to drinking hot water, but it can aid in overall weight loss efforts by increasing metabolism and hydration.