Regarding weight loss and management, intermittent fasting (IF) is one of today’s most discussed diets. Unlike other diets, IF is an eating pattern that cycles between eating and fasting periods. Research suggests that IF can be incredibly beneficial for weight loss (1).
Knowing that intermittent fasting works for weight loss (at least for some people) is one thing, but have you ever wondered what happens in our bodies—specifically during fasting periods—that contributes to weight loss and the other possible benefits of fasting?
The hourly benefits fasting chart aims to educate people on the science behind what goes on behind the scenes—how our bodies react from the minute we stop eating to the minute the feeding window opens.
Read on to learn more about the different fasting stages by day and better understand the processes our bodies undergo.
Contrary to the name, an hourly benefits of fasting chart does not provide an hour-by-hour guide to what happens to your body and the benefits of fasting.
Instead, it is a timeline broken down into four cycle stages.
The stages are as follows (2):
The longer you fast, the more stages you go through, which cause different actions and processes within the body.
Let’s explore the four fasting cycles in more depth to better understand what happens within our bodies when we choose to fast.
This state starts immediately after eating and lasts around three hours (2).
During this phase, the body begins to digest the food you’ve consumed, which means that ghrelin levels have reduced and leptin levels have gone up, contributing to a feeling of fullness.
Your blood sugar levels also increase, triggering the pancreas to secrete more insulin into your system. Insulin allows your body to take glucose into your cells for energy.
Please note that the type of carbs you consume influences how long this fed state lasts.
Whole foods and carbohydrates rich in fiber take longer to digest, sometimes making the fed state last three hours or more. The simple fact that complex carbohydrates take longer to digest means that they are less likely to cause a spike in blood sugar, which leads to more gradual insulin secretion in the body (3, 4).
Any excess energy your body doesn’t need immediately converts into fatty acids, which it stores in the adipose tissue (2).
This stage starts about three hours after eating and may last until around 18 hours after your last meal. At this point, the energy you consume in the fed state is absorbed into your cells, leading to a drop in insulin.
Once insulin levels drop, two metabolic processes occur that produce glucose the body uses as energy:
Glycogenolysis is the breakdown of stored glycogen into glucose.
Gluconeogenesis converts protein and other molecules, such as glycerol or lactic acid, into glucose.
The body’s stored glucose will deplete the longer you fast. If fasting continues without consuming more carbs for glucose production, the body will eventually use most glucose stores and turn to other energy sources. The body will then start to break down triglycerides into free fatty acids for energy, a process called lipolysis that usually begins after 12-24 hours of fasting (2, 5, 6).
The BetterMe: Health Coaching app will provide you with a host of fat-frying fitness routines that’ll scare the extra pounds away and turn your body into a masterpiece! Get your life moving in the right direction with BetterMe!
Once you go without food for more than 18 hours, your body enters this third phase.
The fasting stage can last up to around 48 hours after food intake (2), so people participating in a 36 hour fasting schedule may effectively push their bodies into this stage.
When your body reaches the fasting stage with little glucose left, it can:
Your body converts a portion of the fat into ketones, which your brain and other organs can use as an alternative to glucose. For anyone curious about the benefits of autophagy fasting by hour, animal studies suggest that this process may start anywhere between 24-48 hours without food (8).
However, current research lacks evidence to determine the timing for humans.
Autophagy is how the body recycles old and damaged cell parts.
Problems with autophagy may be associated with certain chronic diseases.
Recently, the media framed autophagy as a health trend, with people hoping to upregulate it by fasting to improve their longevity. However, we need more research to understand the long-term impacts of these trends on human health and diseases (9, 10).
If you go without eating for more than 48 hours, your body enters starvation, which continues until you break the fast by eating something.
Your insulin levels have dropped significantly more than before, and your ketone levels continue steadily rising (2). You’ll also start to limit the conversion of protein to glucose to spare your muscle mass, and your metabolism may generally slow down to conserve more energy.
Most experts advise against reaching this fasting level since starvation can lead to organ failure and death.
The effects of such prolonged fasts are not well studied, so researchers encourage people not to fast for more than two days (48 hours).
If you want to try a prolonged fast, you must do it under medical supervision, where professionals can monitor your health to prevent adverse effects (11, 12).
Read more: Intermittent Fasting Based On Age: Here’s The Truth, As Per Science
There is no good or bad hour to start a fast. When you choose to fast, it comes down to personal preference. Find an intermittent fasting pattern that works for you and decide which hours better suit your lifestyle.
Common fasting preferences:
There is no specific schedule that works for all women. Intermittent fasting schedules are not gender-based, and what works for one woman may not necessarily work for you. Take a look at the different types of IF schedules and experiment with each one to figure out which one works best for:
Generally, intermittent fasting practitioners do it between 12-16 hours daily.
Experts say this fasting duration is enough to experience health benefits.
You do not need to push for fasting 24 or even 48 hours and above to experience the potential benefits.
Reasons why BetterMe is a safe bet: a wide range of calorie-blasting workouts, finger-licking recipes, 24/7 support, challenges that’ll keep you on your best game, and that just scratches the surface! Start using our app and watch the magic happen.
As mentioned above, no specific fasting pattern works best compared to others.
Most people follow the 16/8 intermittent fasting pattern as it’s the most popular and relatively easy to follow.
But, it is by no means better than the rest.
You can choose to fast in any of the following ways and still experience IF benefits:
Read more: What’s the Best Intermittent Fasting Schedule for Muscle Gain?
Simply choose one of the many types of IF patterns and try it out for yourself.
If whatever you picked doesn’t feel right, choose something else.
Once again, remember that intermittent fasting hours are not determined by age, weight, or even sex. It all comes down to personal preference.
We cannot give a specific number for this because weight loss results depend on different and individual factors such as your:
However, we can tell you that healthy and sustainable weight loss equals losing 1-2 pounds a week, i.e., 4-8 pounds a month (14).
You will reach your fitness goal if you keep your progress within these parameters.
You can work out while in a fasted state, but you certainly don’t have to. One study published in the Journal of Exercise Science & Fitness showed that overweight and obese young adult males who engaged in a six-week fasted aerobic workout routine improved their body shape, reduced fasting insulin levels, and increased tissue cell sensitivity to insulin (15). Their counterparts who participated in the same fitness routine but were not fasting also improved all body weight, shape, and blood lipid metrics, except the insulin sensitivity markers. If you exercise while fasting, stay hydrated and do not work out too intensively. Being hungry during strenuous activity may lead to lightheadedness or reduced workout performance. Many look for a fasting chart by age on the internet. However, you don’t need to fast according to age. You should focus on choosing one of the various IF patterns and finding the one that works best for you. There is no research on the most challenging stage of intermittent fasting. However, many people new to intermittent fasting claim that the second and third days are the hardest because they feel hungry. There is no such thing as a specific time for fasting that offers the best results. Start your fasts whenever it feels right for you.Frequently Asked Questions
Can I exercise while fasting?
How long should I fast according to my age?
What is the hardest stage of fasting?
What is the most beneficial time to fast?
The hourly benefits of fasting chart is a guide that shows what happens in your body at different times as you continue to fast.
This guide helps you learn what metabolic processes happen during IF, how long to fast, and when it is most beneficial for you to close your fasting window and eat again.
Remember that extended fasting periods do not mean you will gain more benefits. Fasting for too long can cause adverse health effects. Fasting hours are also not determined by age or sex, and there is no specific best fasting time.
If you try intermittent fasting for weight loss, remember to eat healthy meals, eat on a calorie deficit, and stay hydrated. Always talk to your healthcare provider before fasting or making significant dietary changes. Fasting is not safe or appropriate for everyone.
This article is intended for general informational purposes only and does not serve to address individual circumstances. It is not a substitute for professional advice or help and should not be relied on for making any kind of decision-making. Any action taken as a direct or indirect result of the information in this article is entirely at your own risk and is your sole responsibility.
BetterMe, its content staff, and its medical advisors accept no responsibility for inaccuracies, errors, misstatements, inconsistencies, or omissions and specifically disclaim any liability, loss or risk, personal, professional or otherwise, which may be incurred as a consequence, directly or indirectly, of the use and/or application of any content.
You should always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or your specific situation. Never disregard professional medical advice or delay seeking it because of BetterMe content. If you suspect or think you may have a medical emergency, call your doctor.