A 72-hour fast offers potential benefits like cellular cleanup (autophagy), improved insulin sensitivity, and fat loss, but it's a significant challenge with risks, requiring medical supervision, especially for those with health conditions, as it can cause fatigue, mood changes, and electrolyte imbalances, so it's not universally healthy and depends heavily on individual health status.
Key benefits of a 72-hour fast
Weight loss: Most people experience marked initial weight loss, especially from reduced glycogen and water stores, followed by fat loss as metabolism shifts toward burning ketones.
A 72-hour fast can offer benefits like gut rest, allowing intestinal lining renewal and shifting energy use, potentially improving gut health markers, but it's not a "miracle cure," and research on chronic conditions like IBD is limited, with long-term diet changes being key for lasting microbiome health. While it promotes cellular cleanup and stem cell regeneration in the gut, major changes to your microbiome usually need longer-term dietary shifts, and you should consult a doctor, as prolonged fasting isn't for everyone.
Focus on hydrating, easy-to-digest foods — think light veggie soups, simple smoothies, or bland foods like rice or toast. Avoid foods that are high in fiber, fat, sugar, or spice. These types of foods can upset your stomach and make the end of a fast uncomfortable.
The absolute most important rule is “don't break your fast." It's more important than how many calories you eat each day, or how you structure your meal timing. The core principle needed to take advantage of intermittent fasting is consecutive non-eating hours.
Longer periods without food, such as 24-, 36-, 48- and 72-hour fasting periods, are not necessarily better for you, and may be dangerous. Going too long without eating might actually encourage your body to start storing more fat in response to starvation.
Doctors are cautious about intermittent fasting (IF) due to concerns about potential risks like increased cardiovascular death (especially with short eating windows like 8 hours), hormonal disruption (menstrual cycles), potential for disordered eating, nutrient deficiencies, and lack of long-term safety data, with some studies suggesting general calorie restriction might offer similar benefits, and highlighting IF isn't for everyone, including pregnant, growing, or certain ill individuals.
Preparing for your colonoscopy
Breaking the Fast
Signs that intermittent fasting may be working include 6:
Ketosis starts when your body turns to fat stores for energy due to depleted glucose stores. This usually happens anywhere between 12 and 72 hours into your fast, although the exact timeframe can look different for each person.
When learning how to intermittent fast for weight loss, it helps to keep in mind that intermittent fasting is not a quick weight loss method; it might take a while for you to lose your first kilogram. Some people lose about one kilogram per week, while others can drop up to 5 kilograms in one month.
Eight Common Mistakes People Make While Fasting
Start with Light, Easy-to-Digest Foods
Dates & Water – A traditional and effective way to quickly restore energy and hydration. Soup or Bone Broth – Helps prepare the digestive system for a full meal.
Laxatives: You can drink a polyethylene glycol (PEG) solution or use an over-the counter (OTC) laxative to cleanse your colon. Surgery: If you have severe fecal impaction, your healthcare provider will perform surgery, especially to target symptoms of bleeding due to a tear in your bowel (bowel perforation).
By giving the liver a break from constant digestion, fasting allows it to focus on repairing itself and reducing inflammation. Bile is essential for breaking down fats and removing waste from the liver. Fasting has been shown to improve the liver's ability to produce bile, which can further enhance detoxification.
Fasting may provide a temporary respite from digestion, enabling the gut lining to heal and inflammation to diminish.
As blood glucose levels fall during fasting, the pancreas secretes increased amounts of glucagon. This action also reduces insulin secretion, which in turn decreases glucose storage in the form of glycogen.
For example, a news release published last year after an American Heart Association meeting reported some potentially concerning findings — namely, that people who followed an 8-hour, time-restricted eating schedule, a type of intermittent fasting, had a 91% higher risk of dying from heart disease.
22:2 fasting, also known as the OMAD (One Meal A Day) diet, is a form of intermittent fasting where you fast for 22 hours and eat all your daily calories within a compact 2-hour window, focusing on nutrient-dense foods to support weight loss, improve digestion, and boost mental clarity, though research on its long-term safety and effectiveness is limited. It's an intense, restrictive schedule that helps reduce overall calorie intake and may trigger autophagy (cellular cleanup), but requires careful attention to nutrition during the eating window to avoid deficiencies.
Tips to Prevent Hunger During Fasting
THINGS TO STAY AWAY FROM DURING FASTING & PRAYER.