It takes between three and five hours for the body to stop processing its last meal. After that, between eight and 12 hours, the body begins to burn stored fat. This process usually intensifies between 16 and 24 hours of fasting. After eight hours without eating, the body will start using stored fats for energy.
Your body will continue to use stored fat for energy for the rest of your 24-hour fast. However, it is important to note that longer periods without eating, such as fasting periods of 24, 36, 48, and 72 hours, are not necessarily better for you and can be dangerous. Going too long without eating could actually encourage the body to start storing more fat in response to starvation. At 12 o'clock, it has entered the metabolic state called ketosis (Anton et al.).
In this state, the body begins to break down and burn fat. The question of whether low-carb fat loss is more effective than losing weight on a low-fat diet comes and goes. The premise of the ketogenic variety of low-carb weight loss is that if the body is deprived of glucose, an alternative fuel called ketones is produced from stored fat. How quickly you start to lose body fat isn't affected as much by the carbohydrate content in your diet as by its total caloric content.
The combination of your body behaving as it should, with a small calorie deficit, can mean effortless fat loss without constant hunger. According to Harvard T. H. Chan School of Public Health, when carbohydrates are drastically reduced in the ketogenic diet, often to 20 grams per day, the body first extracts stored glucose from glycogen stored in the liver and muscles and then, when glucose stores are completely depleted, it begins to use fat as main fuel, while dramatically reducing the amount of glucose.
insulin production. When you're in ketosis, ketones made from liver fat are used to fuel the body and brain instead of glucose. In addition to reducing body weight, this fast can help lower cholesterol, improve glucose control, reduce liver fat and improve blood pressure. You can't go wrong choosing complex, unrefined carbohydrates, such as whole grains, green leafy vegetables, healthy fats, and lean proteins.
According to the Mayo Clinic, if you start creating a daily deficit of 500 calories today, either by burning an extra 500 calories during exercise, reducing 500 calories from your diet, or a combination of both, you should lose about a pound less in a week. Intermittent fasting works by extending the period in which the body has burned the calories consumed during the last meal and begins to burn fat. In fact, with intermittent fasting, some of the fat is converted into ketone bodies that appear to reactivate these genes, reducing inflammation and stress resistance in the brain, for example.It's important to remember that for sustainable long-term fat loss results you must take an in-depth look at your habits, behaviors, mentality and beliefs about yourself and the world around you. What matters most when you lose weight is that the losses you see on the scale are mostly fat.
The Harvard T. Chan School of Public Health lists the following supposed theories about how maintaining ketosis can promote fat loss although they note that research has not consistently demonstrated them. Mattson says that after hours without eating the body depletes its sugar stores and begins to burn fat.