People typically link a liquid fast with a cleansing diet, but drinking only nutritive liquids for a short time improves your health in many ways. It can even help you lose weight. Learning about the benefits and risks of a liquid fast will help you decide whether to try this type of cleansing.
Tip
Fasting can decrease blood pressure and body weight as well as help treat arthritis and asthma, according to January 2016 report in Cell Metabolism. These findings suggest that fasting can fight disease and delay aging.
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Learn About the Liquid Fast
People have increasingly turned to fasting to improve their health. Many types of fasts exist, and you should meet with your doctor before starting any of them. Dehydration causes many problems in total fasts, and a liquid fast decreases this risk.
During a liquid fast, you dramatically decrease your caloric intake while staying hydrated with water, juice or broth. Typically, you should avoid dairy products and solid foods in this type of fast.
It's important not to starve yourself during a fast. Instead, you should have a science-based plan. Liquid fasts need only last for a day. For example, the authors of a November 2012 article in the Nutrition Journal tested 54 overweight women and showed that doing a liquid fast one day a week decreased both bad cholesterol and body weight during an eight-week study.
You can also get impressive results after a single liquid fast. The writers of a November 2013 paper in Nutrition, Metabolism and Cardiovascular Diseases tested 30 healthy adults and found several positive changes after a 24-hour, water-only fast.
The liquid diet increased growth hormone and decreased triglycerides. These researchers believe that repeated bouts of short liquid fasts might help you decrease your risk of developing metabolic diseases like diabetes.
Health Benefits of Liquid Diet
A June 2012 paper in the American Journal of Cardiology showed that people who regularly fasted had a lower risk of heart disease and diabetes. Such people also have a lower body mass index.
Digestive changes might play an important role in these results, according to a May 2017 article in Scientific Reports. These researchers tested 20 subjects and showed that drinking only juice for three days caused significant changes to gut microflora. The amount of Firmicutes and Proteobacteria decreased, and the amount of Bacteroidetes and Cyanobacteria increased.
Juice fasts cause other positive changes. The authors of a January 2016 report in Advances in Nutrition had 20 participants drink vegetable and fruit juice for three days. The benefits included decreases in body mass index and body weight. The treatment also caused a massive increase in nitric oxide. This signalling molecule plays an important role in your immune system, according to a March 2015 paper in Trends in Immunology.
Health Risks of Fasting
The liquid meal benefits likely outweigh the risks, but you should stay aware of possible side effects. For example, you will have a difficult time getting enough nutrients while on a liquid diet — especially a clear liquid diet.
According to a July 2017 report from the Mayo Clinic, you can avoid this problem by keeping the fast short. The authors recommended doing this type of fast for only a few days. They also suggested getting at least 200 grams of carbohydrate each day, and spreading it throughout the 24-hour period.
The writers of a March 2012 article in the Journal of Lipid Research tested 18 healthy adults and showed that 48 hours of liquid fasting caused an increase in a type of body fat known as triglycerides. Interestingly, women and men had different responses to the fast. Women accumulated triglycerides in their muscles, while men accumulated them in their livers. The latter effect could lead to liver damage.
Read more: Why Trying a Water Fast Is So Risky
The study in the Journal of Lipid Research also showed a dramatic increase in ketones in both genders. Most people can easily tolerate short periods of ketosis, but pregnant people and people with diabetes should avoid this state. Thus, they should also avoid any type of fasting — unless specifically ordered by their doctor.
You too should avoid long periods of ketosis as it might damage your circulatory system, according to a November-December 2014 report in Epilepsy Currents.
- Cell Metabolism: "Fasting"
- American Journal of Cardiology: "Relation of Routine, Periodic Fasting to Risk of Diabetes Mellitus, and Coronary Artery Disease in Patients Undergoing Coronary Angiography"
- Scientific Reports: "Health Benefit of Vegetable/Fruit Juice-Based Diet"
- Advances in Nutrition: "Health Effects of 3-Day Fruit and Vegetable Juice Fasting"
- Trends in Immunology: "Nitric Oxide Synthase in Innate and Adaptive Immunity"
- Mayo Clinic: "Clear Liquid Diet"
- Journal of Lipid Research: "Effect of Short-Term Fasting on Liver and Skeletal Muscle Lipid, Glucose and Energy Metabolism in Healthy Women and Men"
- Epilepsy Currents: "Danger in the Pipeline for the Ketogenic Diet?"
- Nutrition Journal: "Intermittent Fasting Combined With Calorie Restriction Is Effective for Weight Loss and Cardio-Protection in Obese Women"
- Nutrition, Metabolism and Cardiovascular Diseases: "Randomized Cross-Over Trial of Short-Term Water-Only Fasting"