Can you go without food for 24 hours?
Preventive medicine asks us to pursue healthy habits and incorporate them into our lifestyle. One of those effective habits is fasting. Long fast means fasting for a more extended period of time, which is defined as more than 24 hours.
Most people now practice intermittent fasting but some people are now doing longer periods of fasting because of recognized boost in health and may provide several benefits, such as appetite correction, loss of surplus fat, decreased inflammation (decreased symptoms like bloating or decreased CRP level), decreased blood sugars in diabetics, decreased blood pressure in hypertensives, improved mental clarity, lowered blood cholesterol, prevention of neurodegenerative diseases (eg. Alzheimer’s), and delayed aging.
Longer fasting, however, should be done when you have the time to control your activity and work demands but also when you can stay busy so that you forget you are fasting. It also has a higher risk of complications such as fatigue, weight loss, and nutrient depletion, which is why this should be supervised by a doctor.
So how do we do longer fasting? There is 24-hour fast, which involves fasting from dinner to dinner or breakfast to breakfast. It’s like skipping breakfast and lunch and eating only a single meal a day. You may drink coffee or bone broth in the morning and make sure to eat nutrient-dense food to have adequate proteins, vitamins, and minerals. This is recommended to be done two days every week or every two weeks.
The 5:2 Diet by Dr. Michael Mosley, who wrote the book The Fast Diet consists of five normal eating days and two days of fasting where one may eat up to 500 calories (women) or 600 calories (men) per day. The two fast days can be done on consecutive days or spaced apart while the 500 calories can be consumed in a single or spread into several meals. The 500 calories are kept low to trigger the benefits of hormonal balance during fasting and to increase compliance. Even after reaching your ideal weight, you can still follow the 5:2 diet to maintain weight loss.
The Alternate-Day Fasting is fasting every other day. Just like the 5:2 diet, you can eat 500 to 600 calories on each fasting day. This is a more intense regimen compared to a 5:2 diet and should be followed until you reach your ideal weight.
The 36-hour Fast, on the other hand, is when you fast for the entire day, or fasting every other day. Only fasting fluids like coffee, tea, and bone broth are allowed on fasting days. Some people prefer this because it's very simple: You don’t have to eat the entire day but just drink the recommended fasting fluids. On eating days, it’s recommended to eat whole and unprocessed foods and food high in natural fats, and to stay away from refined carbohydrates. You may also consume breakfast, lunch, and dinner during non-fasting days.
Longer fasting, however, should be done when you have the time to control your activity and work demands but also when you can stay busy so that you forget you are fasting.
The 42-Hour Fast is when you need to fast for the entire day and skip breakfast every day, even on non-fasting days. For example, you would eat dinner at 7 p.m. on day 1. You skip all meals on day 2 and eat your regular breakfast meal in the afternoon on day 3. On fasting days, one can only take fasting fluids.
The 7-to-14-day fasting, is fasting for seven to fourteen days in a row without any meals and you are only allowed fasting fluids during the fasting period. This is often done by athletes at least once a year for detoxification. This is a very intensive regimen and should be supervised by a doctor, especially if you are on maintenance medicine. It is also best to drink multivitamins and supplements to prevent micronutrient deficiency.
Longer fasting regimen should be done two days every week or every two weeks, for six weeks and then rest. Drink unlimited zero-calorie water, tea, coffee, or bone broth during fasting days. And do not forget to stick to a nutritious diet low in sugar and low in refined carbohydrates during non-fasting days.
If you are malnourished or underweight, if you are a child under 18, if you are pregnant or breastfeeding, do not fast.
Be cautious about fasting if you have gout, diabetes, gastroesophageal reflux disease, or ulcer and if you are on maintenance medications.
As a preventive medicine doctor, I believe in the impact food has on the quality of our life. It can heal us or harm us, and what fasting does is help both our body and mind have a better relationship with food, so that we can maximize the benefits it gives.