There is no shortage of weight loss options, but not all of them are effective. Many make sweeping promises but leave more than a fair share of people disappointed in the lack of results. Intermittent fasting, however, offers weight loss benefits in a short time, while also supporting improvements to your overall health.
Detailed below is how you can expect your body to change after a week of intermittent fasting, and how to boost your results.
What Is 16:8 Fasting?
The 16:8 fast is a form of time-restricted eating (TRE) where someone fasts for 16 hours and then eats only during an 8-hour window. Doing this has been associated with weight loss as well as improved body weight homeostasis.
Health Benefits of 16:8 Fasting
Beyond weight loss, there are many other benefits of 16:8 fasting for your health, such as:
- Improve insulin sensitivity. Intermittent fasting has been shown to lower levels of fasting glucose and fasting insulin while also reducing insulin resistance. This has allowed some people with type 2 diabetes to reverse their need for insulin therapy while also lowering blood sugar levels.
- Improve Heart Health. Intermittent fasting improves blood pressure, which can contribute to heart disease if it is consistently high.
- Enhances memory. Studies have shown that intermittent fasting can boost memory and improve executive function.
- Balances female hormones. Some research suggests that fasting can help to decrease androgen levels in females with polycystic ovarian syndrome (PCOS), reducing the symptoms that arise due to this hormonal imbalance.
These health benefits of intermittent fasting occur alongside the health benefits that come from losing weight.
How Much Weight Can You Lose With 16:8 Fasting in a Week?
Intermittent fasting diets reconfigure your body’s energy source. Your body first uses stored glycogen for energy, but once this glycogen is depleted, the body enters a state of ketosis, which is where the weight loss benefits of intermittent fasting lie.
During ketosis, the body converts stored fat into ketones, which it then uses for fuel. This metabolic shift then allows your body to burn fat, promoting weight loss and, more specifically, fat loss.
Research on intermittent fasting diets shows that it can take 8 to 12 weeks to lose 3–8% of your body weight—for someone who weighs 200 lbs, this equates to weight loss of 6 to 16 lbs. Based on this data, you could expect to lose 0.5 to 1.3 lbs per week on intermittent fasting. However, there’s a way to boost your weight loss even more.
In addition to the metabolism shift that intermittent fasting promotes, by shortening to an 8-hour eating window, you naturally consume fewer calories. Since the standard formula for weight loss is to burn more calories than you take in, this decline in calories can naturally aid weight loss, as well, contributing to your 16:8 fasting 1 week results.
A study on calorie restriction found that men who ate between 1500 and 1800 calories per day and women who stayed between 1200 and 1500 calories per day had an average weight loss of 13.9 lbs over 12 weeks. This, combined with the weight loss from intermittent fasting, means you could lose up to 2.4 lbs per week.
How Quickly Do You See Results From 16:8 Fasting?
Mild ketosis develops just 12 to 14 hours after fasting. So, if you follow the 16:8 fasting schedule, where you fast for 16 hours, you can expect to burn fat for a few hours each day. As the days pass and you stay consistent with your fasting, you can start to see results.
To further improve your weight loss, you can combine intermittent fasting with exercise. One study found that ketones were detected in the blood after 21.1 hours with just fasting, but adding exercise to the mix allowed them to be detected after just 17.5 hours. Knowing this, exercise can help your body burn through its glycogen store quicker, requiring it to then convert fat into ketones for more energy.
As for the best time of day to exercise while fasting, one study found that exercising one hour after a meal can reduce the fat oxidation rate, meaning you burn more fat. Knowing this, try to schedule your workouts an hour after you eat.
However, it’s important to keep in mind that not everyone will see immediate or significant weight loss results, even when entering a state of ketosis. When fasting, your daily routines can shift, which can cause your body to feel stressed, especially in the first few days. As a result, your body may retain more water—thanks to elevated cortisol levels—which can then equate to excess weight.
Some other reasons why you may not lose weight on the 16:8 fast can include:
- Insufficient sleep
- Overeating during eating windows
- Extending eating hours
- Improper hydration
- Overeating processed foods
- Underlying health conditions
Being honest with yourself is the first step in seeing results while following an intermittent fasting plan.
What To Prioritize During 16:8 Fasting?
While fasting alone can help your body enter a state of ketosis, making some key changes can help you see even greater weight loss results.
Eat Wisely
Your eating habits matter at all times, but especially when you have a shorter eating window. You have only so much time in the day to consume food, and so it’s important that you make wise choices with the food you decide to eat. Specifically, choosing filling foods with lower calories, such as vegetables, can help you to feel full while lowering your calories consumed.
During your 8-hour eating windows, prioritize healthy foods with:
- Fiber
- Complex carbohydrates
- High protein content
- Healthy fats and oils
This ensures that you are providing your body with the required nutrients, such as lean protein and healthy fats, while avoiding high-calorie, unhealthy foods that provide no nutritional benefit.
Hydration
While some people may experience water retention when first trying 16:8 fasting, that’s no reason to drink less water. In fact, drinking water is even more important when fasting because, when you cut back on food consumption, you have to compensate by drinking more liquids. Drinking water is preferred, but other zero-to-low-calorie beverages such as herbal teas or black coffee can help you get more fluids without breaking a fast.
As a bonus, if you feel hunger pangs during fasting hours, drinking more fluids can help ease your hunger.
Getting Enough Sleep
To keep your energy levels up, it’s crucial that you aim for at least 7 hours of sleep per night. In addition to giving you the energy to go through your day, being well-rested can help with hormonal balance and appetite regulation, which can further support your weight loss efforts.
Research has shown that sleep deprivation can cause the hormone ghrelin to increase, which is what signals hunger to your body. By getting enough sleep, you won’t have the urge to eat, making it easier to keep your calorie consumption down.
Reset Your Body to Lose Weight with Intermittent Fasting
Resetting your body’s metabolism and other physiological processes can help jumpstart your weight loss efforts while also improving your overall health. However, to see results using the 16:8 fast, you must be sure to follow the fasting schedule and develop eating habits that prioritize the right foods. Adding in exercise and sleep, as well, can help you boost your weight loss while following a time-restricted eating plan.
Many people see noticeable weight loss after just one week of the 16:8 fast; give it a try and see if you’re one of them. To help simplify your 16:8 fast, Fasting App: Tracker & Timer can help guide you through your weight loss journey.
FAQs
How long does it take to lose 20 pounds with intermittent fasting?
The amount of time that it takes to lose 20 pounds with intermittent fasting can vary by person. Most people lose 0.25–0.7% of their body weight per week on intermittent fasting, so for a 200 lb person, it could take 15 to 40 weeks to lose 20 pounds.
In some cases, the body may reach a weight loss plateau because it has adapted to the lower calorie intake and uses its stored energy more efficiently. In these cases, you may need to adapt your calorie consumption or up your exercise levels.
How many days in a row should you do a 16:8 fast?
In order to see fat loss from intermittent fasting, it’s recommended that you complete 16:8 fasting every day while following a balanced diet. Fasting App: Tracker & Timer can help you keep track of your intermittent fasting plan and monitor your weight loss progress.
Who should avoid intermittent fasting?
Some people who should avoid intermittent fasting include individuals under the age of 18, pregnant or breastfeeding women, those with a history of eating disorders, and those with type 1 diabetes who take insulin. If you’re ever unsure if intermittent fasting is the right choice for your health, reach out to your doctor.
