Does 16/8 Intermittent Fasting Work? Intermittent fasting is growing in popularity, and the most popular approach is called 16/8, where you fast for 16 hours and take in all your calories within an eight-hour eating window.
16/8 fasting is an excellent way to reduce calories and take advantage of all the hormonal benefits of being in a fasted state for 16 hours.
When you’re in a fasted state, insulin levels are low, making it easier for the body to dip into stored energy (fat and carbohydrates). Insulin is the storage hormone produced and released from the pancreas to control blood sugar, store away excess calories, and promote protein synthesis. When high insulin levels are circulating throughout the body, it’s challenging to burn body fat.
One of the most significant benefits of fasting is maintaining low insulin levels, which will result in increasing your insulin sensitivity. Most people who’ve been overweight for extended periods become insulin resistant. That means their cells are no longer responding to insulin (they are immune to it), leading to metabolic syndrome and several health issues such as obesity, diabetes, high blood pressure, fatty liver disease, and high cholesterol.
The combination of calorie restriction and low insulin levels is why fasting works so well for weight loss and improved health.
If you’re trying to figure out “Does16/8 Intermittent Fasting Work” for weight loss, let’s go over a case study of one of my clients.
I had a personal training client who was doing incredibly well following a 16/8 fasting strategy. She lost about 18 pounds in 10 weeks but then stopped losing weight and gained a few pounds back. As a result, I switched her over to fasting for 24 hours once or twice a week, and she started losing weight again.
Lets’s go over why she initially did so well fasting for 16 hours, why the weight loss then stopped, and how switching to a 24-hour fast jumpstarted her weight loss again.
She was fasting for 16 hours every day. If you fast for 16 hours every day, I would call that Time Restricted Eating because you’re not doing it intermittently. If you fast for 16 hours a few times per week, I would call that intermittent fasting.
When she switched to only eating within an eight-hour eating window, she was pretty dramatically reducing her calories. (Before she began fasting, she typically would eat all day long.) Plus, she was benefiting from all the hormonal effects of being fasted for 16 hours. I think she stopped losing weight after about ten weeks due to the setpoint theory of weight loss. I think her body was trying to get back to her old weight and her metabolism aggressively slowed down. By fasting for 16 hours every single day, she was in a calorie deficit for too long. In response, her metabolism slowed down.
At this point, I gave her three options. She could stop fasting for 16 hours every day and switch to fasting “intermittently” by fasting for 16 hours, only three or four times a week. By doing that, it would help cycle her calories and increase her metabolism. The second option I gave her was to take a two-week diet break and upping calories (to increase her metabolism). The final option she decided to go with was to fast for 24 hours on Mondays and Thursdays while upping her calories and eating normally the rest of the week.
The last option worked well for her. After about two weeks, she started losing weight again and is now down about 24 pounds at her goal weight. She’s maintaining this weight loss by fasting for 24 hours one day a week and experimenting with 16/8 intermittently.
There were also additional reasons why the 24-hour fast worked for her, which I explain in the video.
Best – Mike Cola