Does Intermittent Fasting Work? What You Need to Know
The health world is in love with intermittent fasting (IF).
IF appeals to people who are searching for an approach that is effective, sustainable and doesn’t rely on what you eat but rather when you eat.
Does intermittent fasting work, then?
We’ll look at how it works, what science says about its benefits and risks, and whether it’s the right choice for you.
What is intermittent fasting, and how does it work?
The term intermittent fasting refers to a dietary method consisting of periods of eating and fasting.
IF consists of limiting when you eat, counting calories, and eating foods that you may want to avoid.
However, there are multiple IF schedules that are popular and are meant for different lifestyles and goals.
For example, the most common schedule, 16/8, is where you fast for 16 hours and eat for 8.
Another popular method is the 5:But first, 2 method, you follow your typical diet five days a week, but restrict calories very strictly the other two days.
During fasting periods, the body adjusts physiologically and uses stored fat as fuel.
When you fast, your insulin levels go down, and your body is told to burn fat for fuel.
One reason that intermittent fasting can help with weight loss is because of this process called lipolysis.
It also puts your body into a state of autophagy, which is a cellular repair process that cleans out damaged cells to make room for healthy ones.
Eating and fasting in this cycle can improve your metabolic health, weight loss, and even longevity benefits.
Does Intermittent Fasting Work?
There’s been some research on intermittent fasting and it’s effectiveness, which seems to be promising in regards to weight loss and metabolic health.
There’s a lot of evidence that intermittent fasting can cause massive amounts of weight loss, particularly if you suffer from insulin resistance or metabolic syndrome.
According to a 2015 review, intermittent fasting can cause 3 to 8 percent weight loss over three to 24 weeks, a lot more than other dieting methods (1).
Intermittent fasting is simple and flexible, and for some, it may be better than traditional calorie restriction.
Rather than calorie tracking all the time, you focus on the timing of meals, which will be easier to stick to over time.
Not everyone benefits from IF in the same way, however.
Not everyone will see instant changes or will even try fasting, especially if you have a fast metabolism or a high physical demand.
Intermittent fasting works differently for people based on age, health conditions, and lifestyle.
Benefits of Intermittent Fasting for Health
Intermittent fasting is also good for you, even if you’re not trying to lose weight.
Let’s explore some of the top health benefits people experience with IF:
Weight Loss
We all know that intermittent fasting is good for weight loss.
Fasting causes your body to start using stored fat for fuel, which will result in weight loss over time.
It may also prevent the body from consuming calories by eliminating the need for more than one meal or snack each day.
It’s important to create a calorie deficit in order to lose weight, and they can do that.
Improved Insulin Sensitivity
For people with type 2 diabetes or prediabetes, intermittent fasting can boost insulin sensitivity (2).
When we fast, insulin levels drop, and fat cells release the sugar they’ve stored for energy.
Eventually, it may help to prevent blood sugar spikes and keep energy levels stable.
Cellular Repair
Scientists and health experts alike have been paying attention to autophagy, a cellular cleaning process that takes place during fasting (3).
It destroys damaged cells and reduces the buildup of toxic proteins by recycling cellular components through an act known as autophagy.
It is believed to be involved in longevity and may help prevent diseases such as cancer and Alzheimer’s.
Mental Clarity
Fasting can help people focus better and feel mentally clearer, many say.
This could be because stabilized blood sugar levels mean fewer energy crashes, and the release of brain boosting chemicals like brain derived neurotrophic factor (BDNF) (4).
BDNF supports brain health, promotes the growth of new neurons, and has even been linked to improved mood and cognitive function.
Intermittent Fasting: Potential Downsides and Risks
If you’re looking at intermittent fasting, it has its benefits but it’s not for everyone and it has its potential downsides.
Let’s look at some common risks associated with IF:
Not for Everyone
Pregnant or lactating women, young children, and people with some medical conditions shouldn’t do intermittent fasting.
If you know people who have had eating disorders, they may have an issue with the restriction aspects of IF and may fall into the disordered eating habits.
Side Effects
Intenschester of intermittent fasting, you could have hunger, hormones, and low energy, among other side effects.
During the fasting period, some people get headaches, can’t concentrate, or feel moody.
Side effects are common with these drugs, and they often reduce as the body adjusts, but it’s important to listen to your body and adjust as necessary.
Long-Term Impact
While IF can help you lose weight, some experts worry that it could eventually cause a metabolic slowdown over long periods of fasting (5).
If you’re extended fasting, the body may signal you to conserve energy, resulting in decreased calorie burn and some people's inability to maintain their weight.
How Fast Does Intermittent Fasting Work?
The amount of time you will see results with intermittent fasting depends on how long you fast and how well you can stick to it.
Some people notice changes within a few weeks, especially if they’re following a schedule like 16/8 or 5:2.
Most people notice weight loss and better energy within the first month.
However, remember that some results might seem to come quickly, but progress is usually sustained with IF.
Weight loss is often the first thing that happens in the first 1-2 weeks as the body adjusts to using the stored fat.
However, those benefits may not be immediate, such as improved metabolic health or insulin sensitivity, which can take several months.
So How Much Weight Can You Lose With Intermittent Fasting?
Both starting weight and the fasting schedule matter with weight loss from intermittent fasting being largely dependent upon these two factors.
You can expect around 1-2 pounds per week.
The more you stick to a fasting plan and combine it with balanced meals, the more likely you’ll see gradual, sustainable weight loss.
If you want to improve your results, combine intermittent fasting with mindful eating.
To stay hydrated and avoid hunger, choose nutrient dense foods, avoid processed snacks and drink plenty of water.
Either way, intermittent fasting could help you avoid muscle loss, especially if you’re incorporating strength training or resistance training exercises.
It will help you lose fat without losing muscle, which is healthier weight loss.
Final Thoughts
Fasting intermittently is a very effective way to lose weight and improve your health and even longevity.
IF allows you to use a flexible tool for managing health and weight goals—by eating when you do, rather than limiting which foods you eat.
However, it’s important to remember that intermittent fasting doesn’t apply to everyone.
The results depend on the metabolism, lifestyle, and the consistency.
If you are considering introducing intermittent fasting, do so in baby steps, find a fitting schedule and adapt it so it matches your routine.
Intermittent fasting could be used as a power tool in your health journey with patience and a balanced approach.
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FAQs
So, is intermittent fasting really effective for weight loss?
Yes, you can benefit from weight loss by staying within a calorie deficit and improving fat burning when you are intermittently fast.
How much weight can you lose in a month with intermittent fasting?
With consistent IF, you can expect to lose weight anywhere from 4-8 pounds a month.
But how long should I go on intermittent fasting to see if it will work?
Most people will see changes within 1-2 weeks, but it can take several months for the results to become more permanent.
So, what’s the best intermittent fasting schedule for beginners?
For beginners, the 16/8 or 12/12 fasting windows are usually recommended as being manageable.
Is intermittent fasting for everyone?
Not everyone should do intermittent fasting, especially those with certain health conditions. A visit with a healthcare provider is advised.
Related Studies
1. Title: Research review shows intermittent fasting works for weight loss, health changes
Intermittent fasting has been shown to lead to mild to moderate weight loss (1–8%) compared to traditional calorie restricted diets, a conclusion based on review of over 25 studies.
Link: https://today.uic.edu/research-review-shows-intermittent-fasting-works-for-weight-loss-health-changes
2. Title: The effects of different intermittent fasting regimens in people with type 2 diabetes
Intermittent fasting regimes (fasting two times per week) reduced blood glucose and insulin resistance in diabetic patients, the data showed.
Link: https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2024.1325894/full
3. Title: Fasting for Thought: How Intermittent Fasting Fuels the Brain
Studies show that consuming the same amount of calories at different times can help improve brain-derived neurotrophic factors (BDNF), which helps keep neurons healthy and functioning properly.
Link: https://www.rupahealth.com/post/fasting-for-thought-how-intermittent-fasting-fuels-the-brain
4. Title: Intermittent Fasting and Human Metabolic Health
This review discusses how intermittent fasting can improve mood and cognitive functions, partly through increases in BDNF levels, which are vital for brain health.
Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC4516560/
5. Title: Research review shows intermittent fasting works for weight loss, health changes
The review suggests that while intermittent fasting is effective for weight loss, concerns about potential metabolic slowdown over extended periods are addressed, indicating no significant adverse effects on metabolism.
Link: https://today.uic.edu/research-review-shows-intermittent-fasting-works-for-weight-loss-health-changes
