16/8 Intermittent Fasting: Weight Loss Benefits, Health Considerations and Risks
Aug 14, 2025 • 8 min read
Published on August 14, 2025 | Updated on August 14, 2025
August 14, 2025
If you’ve heard about 16:8 intermittent fasting (IF) and want to give it a try, but all the information out there feels a little overwhelming, don’t worry—this guide breaks it down for you. The 16:8 approach is one of the most popular and beginner-friendly ways to do time-restricted eating, and for good reason. It’s simple: you eat during an 8-hour window and fast for the other 16 hours. This flexible structure fits into most lifestyles without feeling too restrictive or complicated—making it much easier to stick with than stricter fasting plans.
At its core, 16:8 intermittent fasting means eating all your meals within an 8-hour window and fasting for the remaining 16 hours. There are no complicated rules or special foods required, and you don’t need any calorie counting or macro tracking. Instead, the fasting periods make your body burn fat:
After about 12 hours without food, your body begins to shift from burning glucose to burning stored fat for energy, a process known as the metabolic switch.
The metabolic switch activates fat burning, which makes 16:8 intermittent fasting especially effective for losing fat and supporting metabolic health. A PMC study on IF and human metabolic health showed 84.6% of studies reported weight loss with intermittent fasting.
Of course, you can also opt for a different type of fasting like 18:6, 20:4 or alternate-day fasting, but 16-hour intermittent fasting is considered a moderate and sustainable entry point.
IF isn’t just a trend—research supports its effectiveness. In a 2021 systematic review, 84.6% of intermittent fasting studies showed significant weight loss among participants.
Positive effects were even greater when fasting was paired with healthy food choices and lifestyle habits. Although 16:8 intermittent fasting isn’t a cure-all and shouldn’t be seen as a magic fix, it can provide several health benefits.
One of the most common reasons people try 16:8 intermittent fasting is weight loss. Eating within an 8-hour window naturally limits the number of times you can reach for food. That often translates to fewer overall calories. In a 12-week study by the University of Illinois, participants following the 16:8 pattern lost an average of 3% of their body weight and consumed about 350 fewer calories per day, without trying to restrict portions.
Fasting also gives your body a break from processing food around the clock, which can help improve insulin sensitivity and blood sugar control. A 2018 study found that time-restricted eating improved insulin levels, blood pressure, and β-cell function—even in men with prediabetes, and even without weight loss.
Other study participants on an 8-hour eating schedule spent 3.3% more time in a healthy blood glucose range. That’s a small but meaningful improvement for long-term health.
IF 16:8 may also have benefits beyond the scale. IF seems to have a positive impact on the brain performance and also on the cardiovascular system. According to a 2019 study on IF in cardiovascular disorders, a 16-hour fasting diet helps lower blood pressure and may support a better cholesterol balance. The study's results also suggest that fasting strengthens the brain-derived neurotrophic factor (BDNF), which supports memory and focus.
A 2022 study demonstrates that time-restricted eating (TRE)—a form of intermittent fasting—can play a meaningful role in preventing type 2 diabetes. TRE, which involves eating within a specific daily window (typically 4-10 hours), produced mild but consistent weight loss (8.5% of baseline body weight) and reduced fasting insulin levels, both of which are key factors in mitigating diabetes risk.
According to research from Manchester Metropolitan University, individuals following an 8-hour TRE experienced improved glycemic stability throughout the day. This also enhances insulin sensitivity and reduces the risk of hyperglycaemia, making IF a promising strategy for those who want to regulate glucose levels and support metabolic health.
To benefit the most from 16:8 intermittent fasting, you should set the right time frame. One of the reasons it has become so popular is its relative flexibility:
One of the most common methods. You delay your first meal until noon and finish dinner by 8 p.m. This works well for people who don’t wake up hungry.
You prefer an early start? Then eat breakfast at 8 a.m. and have a light lunch or early dinner by 4 p.m. Early risers or those with no evening social commitments often choose this approach.
If you are someone who sleeps in or works late, 10 a.m. to 6 p.m. can be your best time frame. You have enough time for two solid meals and a snack, without feeling rushed.
If you find an 8-hour window for food that suits your day, you are more likely to sustain IF long term. Within the 8-hour eating window, most people eat 2 to 3 meals and a snack. Over time, your body is likely to adapt to the new rhythm, making hunger and energy levels more predictable.
One of the biggest perks of 16:8 intermittent fasting is that this diet plan doesn't require you to eliminate certain food groups—there are no fixed rules on what you can eat or drink while intermittent fasting.
You can eat calorically dense food during intermittent fasting, but choosing healthier foods will give you better health and weight loss results in the long run. Many people follow the 80/20 rule: they eat nourishing, whole foods 80 % of the time and consume “unhealthier” things the other 20%.
When following the 80/20 rule, you should focus on:
Nutrient-dense foods
High-quality protein
Healthy fats
Plenty of fibre-rich vegetables
Whole foods
Instead of “perfection”, the focus is on staying full for longer, supporting blood sugar stability and minimizing cravings. Avoid drastically cutting calories—fasting is not about deprivation.
While 16:8 intermittent fasting has plenty of potential benefits, the shift in routine can be challenging. If you want to give it a try, keep the following things in mind:
It’s completely normal to feel hungry or even a little irritable during those first few fasting hours, especially if you’re used to snacking late or eating right after waking up.
During the adjustment period of 16:8 intermittent fasting, some people experience energy dips or sluggish mornings, especially if they’re exercising in a fasted state.
It may take you some time to figure out whether you feel better working out before or after your eating window.
Life doesn’t always follow an eating schedule. Family dinners, brunch invites, or holiday events might fall outside your chosen window. Some people work around it by shifting their window slightly on occasion.
Please note that fasting isn’t recommended for everyone. If you’re pregnant, breastfeeding, under 18, or have a history of type 1 diabetes or disordered eating, it may not be right for you. Be mindful not to overeat during your eating window. It can be tempting to make up for lost time, but this can backfire by cancelling out the benefits of the fast. It’s best to speak with your provider before starting any new dietary plan.
Yes, 16:8 intermittent fasting can support weight loss. Most people go through a short adaptation time of 1 to 2 weeks, where hunger patterns, energy levels, and meal timing may feel a bit off. After that, your body begins to get used to the new rhythm.
A 2023 study found that, over six weeks of daily fasting, men lost 1.8 kg (≈4.0 lb) and women lost about 1.3 kg (≈2.9 lb). Similarly, research by the University of Mississippi found that 16:8 fasting in combination with exercise leads to better fitness improvements than exercise alone.
Consistent weight loss is easier to maintain long-term and far gentler on your body than crash diets. Try these 30 Zero-Carb Snacks to stay full for longer while you do 16:8 intermittent fasting.
The method holds up well in terms of effectiveness. In a 2018 study, people following a 16:8 routine lost 3% of their body weight over 12 weeks, without strict calorie tracking. But one of the greatest benefits of intermittent fasting 16:8 might be sustainability. Research shows that it has far lower dropout rates than more aggressive fasting styles.
Like any wellness strategy, 16:8 intermittent fasting is not a one-size-fits-all solution, but it can be a helpful tool if you don't know how to change your eating habits to be healthier or manage your weight without counting calories.
It’s especially well-suited for:
Beginners new to intermittent fasting
Busy professionals who prefer fewer meals and less meal prep
People who want a flexible, low-maintenance routine
Anyone seeking a gentle reset without major restrictions
Always keep in mind that your personal health history matters. If you’re unsure whether a 16-hour fasting diet is right for you, a registered dietitian or doctor can help you weigh the pros and cons.
If you want to give 16:8 intermittent fasting a try, a thoughtful, gradual approach can make the transition smoother and the diet much more sustainable. These tips can help you get started.
If you are used to eating from early morning to late evening, jumping straight into a 16-hour fast can feel intense. Instead, you could start with a 12:12 schedule and progress to 14:10, then 16:8 over the course of a few weeks.
Pick an 8-hour window that matches your natural routine. If you’re not a breakfast person, you can start your 16-hour intermittent fasting from noon to 8 p.m. If you tend to rise early, then try to use an 8 a.m. to 4 p.m. routine. Whatever you choose, try to keep it consistent.
Water is your best friend, especially during the 16 hours of intermittent fasting. To help you stay energized, you can also try these 5 zero calorie drinks for intermittent fasting. Other drinks that won't impede weight loss are:
Black coffee
Unsweetened tea
Sparkling water (as long as it’s calorie-free)
During your eating window, plan balanced meals by focusing on nutrient-dense foods. Don't restrict calories too severely during your eating window; instead, aim to meet your nutritional needs and listen to your body’s hunger and fullness signals.
To support satiety and overall health, include:
plenty of protein
healthy fats
fiber
Beginner pitfalls are:
Overeating to compensate for the fasting hours
Inconsistent meal timing
Starting too restrictively and burning out
Ignoring hunger cues (honor your body's signals!)
Skipping meal prep, which can lead to poor choices
Start slow, stay flexible, and listen to your body. That’s how 16:8 intermittent fasting can become a habit that lasts. Research supports its benefits for weight loss and metabolic health. It is a beginner-friendly and flexible way to improve health, but it is not for everyone. With a little patience, you can get used to 16:8 intermittent fasting and achieve real results.
This article is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional advice or help and should not be relied on to make decisions of any kind. Any action you take upon the information presented in this article is strictly at your own risk and responsibility!
