Fasting expert Jason Fung, MD, a nephrologist (kidney specialist) and author of “The Complete Guide to Fasting”, explained that intermittent fasting raises growth hormone levels and lowers insulin levels, both of which help burn more fat.
Dr. Fung works with overweight patients with diabetes, and fasting is what has helped them lose weight, reverse their diabetes, and get off medication. He said that weight loss is all about insulin levels. “If insulin is low, then the body can get its energy from fat stores.” People who fast actually find that hunger decreases, which is why I can help people who have issues overeating. When doing any form of daily intermittent fasting, you aim to eat your daily calories, just in a shorter eating window.
To find out your target calories, you need to calculate your basal metabolic rate (BMR) and total energy expenditure (TDEE) To make things easier, complete our diet quiz on our website to find how many calories you should eat a day for weight loss.
Without much disruption into your daily schedule, you basically skip breakfast and then have your dinner on the earlier side so it’s easy to maintain every day. Fasting is also a great method if you tend to go to bed earlier so you’re not hitting the sheets with a full stomach. You can just start a new habit where you curl up on the couch with a hot cup of herbal tea.
Since you’re consuming all your daily calories within a shorter window, another pro is that you can sit down and eat larger meals and feel more satiated than if you were eating three to six small meals throughout the day. And even if you skip breakfast, you can still eat the breakfast foods you love; you’ll just be delaying your meal until later in the day.
Once you get past the first week or two of fasting, you won’t even feel hungry and you’ll wonder why you were eating breakfast all these years. You’ll save money and time buying and preparing food and be able to devote your brainpower to other areas of your life. You’ll feel less bloated, more clear-headed, and lighter in mind and body.
For those who are used to eating all day long, limiting your meals and snacks to a stricter time window may seem impossible. It can also be tough if you have to consume a ton of daily calories as you might find it hard to eat as many as you need without feeling stuffed. If you’re going from 14:10 protocol to a more advanced 18:6, it’ll take a few weeks to get used to cutting your eating window by several hours. Also, if you don’t make a point to eat enough calories, or eat enough protein and healthy fats, 18:6 may cause you to feel hungry or tired.
Any form of intermittent fasting, especially 18:6, since it’s so strict, could potentially be a trigger for unhealthy behaviors for those with a history of eating disorders.
Lisa Eberly Mastela, MPH, RD, told POPSUGAR that any form of IF should be done under the supervision of a registered dietitian, and any diet that encourages a restrictive eating schedule really should be approached with caution from the start. You might be fine doing a less rigid form of intermittent fasting, such as 16:8, but if you have any doubts, it’s best to talk to a doctor, dietitian, or therapist. Intermittent fasting shouldn’t negatively affect your life.
Daily fasting checklist
All fasts, whether a short daily or longer duration all have some common strategies you can employ that will help foster a positive experience with fasting.
There is a learning curve for fasting. Adaptation for frequency and duration of different fasting methods must be respected. Best practices include increased water consumption, electrolyte consumption, understanding hunger signals, and staying busy. Let’s dive into each of them one by one:
1. Know your why. Starting a fast with a set of intentions can help you make powerful changes and give you a clear course toward your goals.
2. Stay hydrated. Give your water a nutrient-boost by infusing with slices of lemon, cucumber, fresh mint, and ginger. Aim to drink half your body weight (pounds) in ounces of water every single day.
3. Eliminate processed foods. Processed foods are loaded with preservatives, chemical additives, synthetic dyes, and artificial flavorings, but skimp on beautifying ingredients. These ingredients trigger inflammation and cause an overload of free radicals in the body. Swap processed foods for fresh and natural foods to free up energy in your body to rejuvenate, repair, and boost your overall health.
4. Move your body. Exercise not only burns calories but helps regulate appetite and fullness, thanks to a specific protein secreted by muscles when they contract. Aim for 30 to 60 minutes during feed hours or just before breaking your fast, five to six days a week with a combination of cardio, strength training, and calming exercises in your workout routine.
5. Consume More Salt Whilst Fasting. Yes. More salt. One of the best strategies for regulating sodium is to eat more of it. This runs contrary to what most larger health organizations advocate for. But low levels of salt, have been linked to insulin resistance, which supports the development of Metabolic syndrome, Diabetes, Alzheimer’s, and other neurodegenerative changes.
When you fast, there will be a natural drop in serum insulin levels. As such, you will just naturally eliminate more fluids and sodium.
Sodium is essential for life. So here’s an easy hack for you. Dissolve 1⁄2 tsp of sea salt in a big glass of water, and drink up. This should mitigate most “flu-like” symptoms.
6. Stay busy. Get a book, dive into a project at work, go for a walk, exercise, spend some time doing what you love.
Don’t look at pictures of food, or other food cues like cooking, smelling food, watching cooking shows, or listening to food being cooked.
These will basically elicit a Pavlovian-like response that a meal is coming, and your body will begin to prepare for it, whether you are eating or not.
So don’t set up shop to work in a bakery all day, or all you’ll want is eclairs.
7. Understand Your Hunger. You will feel hungry during a fast. This is normal. And temporary.
The hours around when you typically eat you should expect to hear more grumbling and to feel the most hungry.
This feeling is a normal part of homeostasis to ensure you are being adequately fed. The more often you will fast – the sooner the hunger response will disappear.
Fasting protocols for beginners
If you are just starting out, begin your journey by skipping your breakfast. Focus on consuming all your calories in a 10-hour window, before fasting for 14 hours. We recommend starting your eating window between 10 am and 12 pm to finish your last light meal by 10 pm in the evening at the latest.
Progress to a shorter feasting window by consuming all your meals in a 9-hour window, before fasting for 15 hours. We recommend starting your eating window to 11 am and 12 pm to finish your last light meal by 10 pm in the evening. This will allow you to take advantage of a more clear state of mind in the morning, making your waking hours more effective.
Most popular fasting protocols
Feel how your mind operates with extra sharpness, incredible focus, and attention to detail. This plan is also flexible. If you prefer eating a later lunch, you can shift your eating window (2 p.m. to 8 p.m.), or shift it earlier (10 a.m. until 4 p.m.). We recommend the former leaving enough time for digestion and ensuring you optimize your circadian rhythms for the restful night ahead.
This is a much more rigid form of intermittent fasting, and definitely best saved for experienced fasters who’ve tried other methods. This plan might be right for you if your weight loss has stalled doing 16:8 or if you tend to overeat with a longer eating window. A common time to break this fast is around 1 pm to 3 pm.
Alternating between 24 hours fasts and regular eating windows every week is known as the Eat-Stop-Eat diet, it involves eating no food for 24 hours at a time. It is recommended to not exceed the frequency of such protocol more than twice a week. Eating a large meal immediately after such a fast can strain the digestive system so consider breaking the fast with a small snack 30 minutes before a bigger meal.
We will often recommend 36-hours fasts 2-3 times per week for type 2 diabetes. From experience, this longer fasting period produces quicker results and still has good compliance. Since type 2 diabetics have more insulin resistance, the longer fasting period is more effective than more frequent shorter fasting periods.
42 hours fasts and beyond
We often advise our clients to make a routine out of skipping the morning meal and break their fast around the noon hour. This makes it easy to follow a 16:8 fasting period on regular days. After a few days, most people start to feel quite normal just starting their day with a glass of water and their usual cup of coffee.
When you combine that with a 36-hour fast, you get a 42-hour fasting period. For example, you would eat dinner at 6 pm on day 1. You skip all meals on day 2 and eat your regular ‘breakfast’ meal at 12:00. This is a total of 42 hours.
For longer duration fasts, we often try NOT to calorie restrict during that eating period. Often, as people get used to fasting, we hear very often that their appetite starts to seriously go down. Not up. Down. They should eat to satiation on their eating day.
There’s a very good reason for this decrease in appetite. As you start to break the insulin resistance cycle, insulin levels start to decrease. In response, hunger is suppressed and total energy expenditure is maintained. So – appetite goes down and TEE (total energy expenditure) stays the same or goes up. Remember that chronic every day caloric restriction strategies produce the opposite. Appetite goes up and TEE goes down, likely leading to inferior results.
You can extend fasts much longer. The world record was 382 days (not recommended!), but there are many people who can fast 7-14 days without difficulty. Indeed the Master Cleanse used by Beyonce is simply a variation of the 7-day fast which allows some concoction of maple syrup, cayenne pepper, and lemonade.
There are some theoretical benefits of stimulating autophagy, a cellular cleaning process which often requires 48 hours of fasting or more. A state of ketosis may require over 36 hours of fasting to enter. There are many theoretical benefits, including appetite suppression and greater mental clarity. For cancer prevention, some recommend a 7-day fast. Many of these benefits are theoretical and unproven, however. Nevertheless, many have found the 7-day fast much less difficult than one initially imagines.
Risk of complications of fasts longer than 24 hours
As you progressively go longer in fasting, the benefits accrue faster, but there is also more risk of complications. Since we often deal with type 2 diabetics and hard to treat obesity cases, we tend to gravitate towards longer fasting periods, but you must understand that we always monitor very closely their blood pressures, and blood work and progress. We cannot stress enough, that if you do not feel well at any point, you must stop. You can be hungry, but you should not feel sick.
Another major consideration is that medication must be carefully monitored by a physician. The major problem is diabetic medications because if you take the same dose of medication and do not eat, you will become hypoglycemic and that is fairly dangerous.
Blood sugars going low is not a complication per se, because that is generally the point of fasting. We want the sugars to go low. However, it does mean that you are overmedicated for that day. You must work very carefully with a physician to adjust medications and monitor sugars. Also, there are certain medications that may cause stomach upset on an empty stomach. NSAIDs, ASA, iron supplements, and metformin are the major drugs here.
In general, diabetic medicates and insulin MUST be reduced on the fasting day to avoid hypoglycemia. Exactly how much to reduce it should be overseen by your physician.
We do not recommend anybody who is taking medication to try longer fasts without clearing it with their doctor.