Fasting can be a beneficial way to give your body a reset and clear that backlog of excesses. It is important that you do this safely, as fasting for longer than 24 hours without medical supervision can be dangerous. If you are medications, you may also need to adjust the doses even if you skip just one meal – so If you do plan on undertaking any form of fasting, be sure to check with your health care provider before doing any form of fasting.
There are many different types of fasts: intermittent fasting where you eat within a certain time window, juice fasting where you only drink juice and give your digestive system a rest, and water fasting where you only consume water - this involves a drastic reduction in calories and is the most powerful tool to induce autophagy when done safely under medical supervision.
Caloric restriction have both shown to significantly extend lifespan and reduce chronic disease in many organisms from fruit flies to mice. It is proposed that when an organism undergoes calorie restriction, it kicks into survival mode during which it starts to conserve energy, become efficient and gets rid of that which not longer serves its purpose i.e. a process called autophagy.
Autophagy is a process by which the body gets rid of non-functioning or abnormal cells, and in doing so, prevent diseased cells from proliferating out of control. It is not the calorie-restriction itself that provides the benefits of fasting, however. Research is pointing to the fact that it is mainly during the re-feeding phase that the benefits and cellular regeneration occurs e.g. studies have shown for example an increase in peripheral stem cells in the re-feeding phase. You also get processes like mitochondrial biogenesis (new mitochondria being made inside the cells during the re-feeding phase, which can lead to better energy production.
Fasting also gives our overworked digestive tracts a little break. When the gut is busy digesting food, it uses a lot of energy and cannot repair itself. So when you take a break from food, the digestive tract has a chance to now repair itself. Studies have demonstrated that fasting can increase beneficial bacterial strains like Akkermansia in our gut and improve microbiome diversity and thus gut health. Akkermansia has been shown to be correlated with our metabolic health, and may play a role in preventing obesity. When we fast, our insulin levels drops – this then allows the body to tap into the fat stores and burn fat as energy. It is very difficult for the body to burn fat when insulin levels are high (e.g. in patients with
type 2 diabetes). This may explain why fasting can help improve insulin sensitivity, and Dr Jason Fung has reversed type 2 diabetes in patients with a fasting program he terms Intensive Diabetes Management program. Also, as discussed above, fasting can improve our gut microbiome diversity and we know that the microbiome plays an important role in how our food is digested and handled, and this may also explain why fasting can improve metabolic health. Other benefits of fasting may also include lower blood pressure, lower cholesterol, and a reduction in IGF-1 (a hormone in our body that has been correlated with increased risks of certain cancer and diabetes when high). If you want to try fasting, make sure you do so safely – and remember, the food that you nourish the body with after a fast is just as important as the calorie restriction itself. So make sure you follow a fast with a healthy, whole food plant-based diet to gain the maximal benefits.