Fasting has gained in popularity in recent years for good reason - it is used to improve or even reverse various health issues and is generally safe to use if done properly
So how does it work?
Our bodies can burn energy from either glucose or ketone bodies When we eat, food is converted to glucose, and absorbed into the blood, which our cells take in and use for energy After about 12 hours of not eating, the body runs out of glucose and starts burning fat stores ( ketosis). Human bodies are highly efficient at producing energy from ketosis- the longest ever recorded fast was 382 days!!
When you fast: Fat stores are converted to energy, ie you lose weight Insulin levels stabilise, leading to less fluctuations in blood sugar, better energy levels, improved mental clarity, and less sugar/carb craving This also improves blood sugar control in diabetics/prediabetics, and has even reversed diabetes in clinical trials Fasting triggers metabolic pathways that 'clean up' waste products and remove damaged cells (apoptosis), This may reduce the risk /progression of cancer, and is even being trialled as a way to boost cancer treatment and reduce side effects
Fasting also reduces inflammation and improves immune function It has been shown to help many autoimmune conditions ie rheumatoid arthritis, inflammatory bowel disease, and multiple sclerosis Fasting reduces DNA damage, and may help you live longer Fasting also stimulates production of BDNF (a protein that stimulates brain growth and connections). It may delay onset, and slow progression neurodegenerative disease such as alzheimers and parkinsons, as well as improving recovery from stroke/spine injury /brain injury Fasting reduces blood pressure, and improves cholesterol and therefore heart health
There are several different ways to fast, they all work! Many people choose time restricted eating as its easy to do and sustainable This means consuming no calories for a period of time - minimum 12 hours, ideally around 14-16 hours (ie 16:8 diet) During this time you can drink unsweetened clear liquids Other fasts include alternate day fasting ( 5:2 diet), intermittent 24h fasts, or longer 3-5 day fasts. Fasting mimicking diets are also popular, where you consume a very low calorie diet for up to 5 days designed to trick your body into fasting