Combining moderate intensity exercise three times per week with intermittent alternate day fasting can double the weight loss achieved with intermittent fasting alone. During a 12-week intermittent fasting obese patients lost 6.6 pounds while patients who also participated in the moderate intensity exercise program three times per week lost 13.2 pounds in the same period as has been shown by a study by Bhutani et al, 2013.
Prolonged very low calorie diets can cause physiological changes that can lead to the body becoming accustomed to calorie restriction, preventing further weight loss. Intermittent fasting on a 16:8 rhythm tries to solve this problem by alternating between a 16-hour meal break and 8 hours of normal eating, which can prevent these adaptations.
Intermittent fasting is only eating during a certain period of time. For example, only eating every other day or only for five days a week. The best-known form of intermittent fasting is to simply skip breakfast and eat only in an eight-hour time window, e.g. between noon and 8 p.m., in the so-called 16 : 8 rhythm. What speaks in favour of this form of fasting is that relatively few changes to the existing eating behaviour are necessary, because one only has to leave out breakfast and not eat anything after 8 pm in the evening.
The best hours for intermittent fasting are from morning until after lunch. Depending on what time you have breakfast either from 7:00 to 15:00 or from 8:00 to 16:00. The meal time window early in the day allows for enough distance to bedtime in the evening. Sleep is better when there are at least three hours between dinner and bed.
In the case of intermittent fasting the best meal to skip is dinner. Fasting in the evening and overnight is the best way of intermittent fasting to lose weight. Eating in the morning, when your mental and physical demands are highest, gives you the energy you need to perform at your best. Studies show that people who eat breakfast do better on cognitive and memory tests than those who skip it. The brain operates better when it is supplied with energy than in a fasting state.
Eating nothing for 16 hours causes the metabolism to go into a short fast. The human body switches on a process called autophagy after 14 to 16 hours without food. In this process, the body seeks the energy it needs from its own damaged proteins or cell organelles, which it smuggles inside autophagosomes. Autophagosomes are vesicles with a double membrane that enclose proteins, lipids, membrane components and whole organelles (mitochondria) from the cell plasma inside them. The autophagosomes then fuse with lysosomes to form autophagolysosomes, where the particles are degraded by acid hydrolases and their basic building blocks are made available for recycling.
Fasting alters the gut microbiome. Intermittent fasting can alter the composition of the human gut microbiome by increasing taxonomic diversity. Fasting alters the gut microbiome reducing blood pressure and body weight in metabolic syndrome patients.
The microbiome is the community of all microbes, such as bacteria, fungi, viruses, and their genes, that naturally live on our bodies and inside us. The microbiome consists of trillions of microorganisms (also called microbiota or microbes) of thousands of different species. In a healthy person, these microorganisms coexist peacefully, with the largest numbers found in the small and large intestines. The microorganisms living on and in us contribute in big ways to our health and well being.
Intermittent fasting can induce distinct microbiome changes impacting anaerobic gut bacteria that produce short-chain fatty acids through saccharolytic fermentation of complex resistant carbohydrates (e.g., fructo-oligosaccharides, sugar alcohols, resistant starch, inulin, and polysaccharides from plant cell walls), which escape digestion and absorption in the small intestine.
Short-chain fatty acids are fatty acids of two to six carbon atoms with the highest levels found in the proximal colon. Short-chain fatty acids have diverse physiological roles in body functions. They can affect appetite and cardiometabolic health. Additionally they may have an impact on mental health and mood.