Is fasting food for weight loss? You may have seen some success stories all over the internet, but is there actually science behind fasting for weight loss? Today, I'm breaking down the details on Intermittent Fasting and weight loss.
Is Fasting Good For Weight Loss?
A multitude of studies and scientific reviews have found that fasting is a useful tool for achieving a weight loss goal.(1) Something that appears to be unique to Intermittent Fasting vs. simple calorie restriction is its ability to lose body fat without significantly losing muscle.(1) This is crucially important because maintaining muscle mass helps us to maintain bone health and insulin sensitivity.
But why is Intermittent Fasting different than calorie restriction in its effects on weight loss? It all comes down to the storing hormone insulin. When we eat, our storing hormone insulin shoots up in our blood supply. This effectively shuts off the fat burning process called lipolysis. With fasting, there are periods of the day when insulin levels will remain low due to not eating. This allows lipolysis (fat burning) to remain on. This is likely why Intermittent Fasting has been found to be uniquely great at burning fat, specifically around the belly. (1,2) In contrast, grazing or eating multiple small meals throughout the day can keep insulin levels elevated throughout the day, effectively turning lipolysis (fat burning) off.
Intermittent Fasting also appears to be superior at keeping hunger levels down, as one review of Intermittent Fasting and weight loss discovered.(1) This comes as no surprise to those incorporating Intermittent Fasting (the right way), as many start to experience greatly reduced hunger levels and even reduced sugar cravings within a few days of implementing an Intermittent Fasting protocol.
How Long Should You Fast To Lose Weight?
Fasting can range from daily Intermittent Fasting to extended multiple day fasts. So which should you be using in order to achieve a weight loss goal? From my experience as a nutritionist working with hundreds of men and women around the world, a shorter daily fast is the easiest to implement while still seeing great results. This can range anywhere between 14-18 hours of fasting per day and a corresponding 6-10 hour daily eating window. In fact, you can take my free quiz on how to determine your best Intermittent Fasting schedule below.
So if low insulin levels means more fat burning, then doesn't that mean that longer fasts will result in greater weight loss? There are certainly therapeutic purposes for using extended multiple day fasts. However, as a long term approach to maintaining sustainable weight loss, this is not something I typically recommend incorporating. Obviously, you can't fast forever, which means eventually you'll need to eat. If you haven't incorporated a sustainable eating protocol, then you may experience a constant cycle of extended fasts, followed by weight gain.
This is where Intermittent Fasting can be quite useful to achieve and maintain a weight loss goal.
However, if you aren't addressing the meals during your eating window, this can result in zero weight loss or even weight gain with Intermittent Fasting.
Take Monica as an example. Monica had previously used Intermittent Fasting without addressing her food and felt miserable and hungry throughout the process - while not seeing any significant results. Once she addressed her meals using the Complete Intermittent Fasting Bundle protocols and recipes, she was able to sustainably achieve her weight loss goal while feeling amazing in the process! Now two years later, not only is Monica maintaining her progress, she's able to add in new fitness goals and create balance with her life.
"I had only set out to lose 5 or 10 pounds, but I actually lost nearly 25 pounds over the course of three or four months! ...I have stopped obsessively counting calories and living in what felt like a persistent state of starvation."
If you are using medications, it's critical to discuss with your doctor your new Intermittent Fasting routine. There may need to be adjustments made to your medications or timing of medications while implementing Intermittent Fasting.