Belly fat is one of the most stubborn types of fat to lose, and it can have detrimental effects on your health. However, with the rise of intermittent fasting as a popular weight loss method, many are wondering what the best fasting window is to specifically target belly fat.
In this article, we dive into the science behind two main methods of Intermittent Fasting and which one may be the best option for losing belly fat.
Understanding Intermittent Fasting
Intermittent fasting is a fascinating nutritional tactic that entails oscillating between periods of fasting and consumption. Several intermittent fasting approaches exist, but the most prominent ones include:
Time-restricted eating, where you must consume all your means within a specific time frame of 8-10 hours daily.
Alternate-day fasting, which involves alternating between days of typical eating and days of severe caloric restriction, typically to a mere 500 calories per day.
5:2 fasting, where you must adhere to a routine diet for five days of the week and limit your caloric intake to a paltry 500-600 on the remaining two days
Intermittent fasting induces a state of ketosis in the body, which is a metabolic state where the body utilizes stored fat for energy rather than glucose. This can result in weight loss, especially in the abdominal region, where fat is frequently accumulated.
The Best Intermittent Fasting Window for Losing Belly Fat
So, what is the best intermittent fasting window for losing belly fat? The answer is that it depends on your individual goals and preferences.
At first glance, longer fasting periods, such as alternate day fasting (ADF), may appear to be the best option for losing belly fat. However, recent studies have discovered that this type of fasting actually decreases the body's ability to burn fat (lipolysis) specifically around the belly(1).
This is likely due to the fact that longer fasts can increase the levels of the stress hormone cortisol, which is linked to weight gain around the belly and can cause the body to become more insulin resistant, thereby making it less efficient at burning fat as fuel.
On the other hand, a human study has shown that a daily 16-hour fast (time-restricted eating, TRE) leads to increased fat loss, particularly around the belly. Further research has been conducted on specific TRE timeframes for even better outcomes, with recent studies demonstrating that "early time-restricted feeding" (eTRF) can improve cortisol levels(2).
To optimize Intermittent Fasting for belly fat loss, an eTRF window may be the best option. However, studies are still uncertain about the optimal time to initiate the fast for the best outcomes. Nonetheless, consistent findings from eTRF research indicate that beginning the fast before 8 pm (thus having the last meal before 8 pm) is preferable. For instance, a 16-hour daily fast with an eating window of 10 am-6 pm could be considered eTRF(3).
However, when specifically targeting belly fat loss, it is critical to address not only when you eat but also what you consume. Specific foods directly stimulate insulin and may work against your goal of losing belly fat. To optimize your meals for Intermittent Fasting, consider utilizing the Complete Intermittent Fasting Bundle.
Other Tips for Losing Belly Fat with Intermittent Fasting
While intermittent fasting can be an effective tool for losing belly fat, it's not a magic solution. Here are some additional tips for maximizing your results:
Focus on nutrient-dense foods: Make sure you're eating plenty of whole, unprocessed foods, including lean protein, fruits, vegetables, whole grains, and healthy fats.
Stay hydrated: Drink plenty of water and other non-caloric beverages to stay hydrated and help control hunger.
Incorporate exercise: While intermittent fasting can help you lose belly fat, combining it with regular exercise can be even more effective.
Get enough sleep: Aim for 7-9 hours of sleep each night to help regulate hormones and prevent belly fat storage.
- Chow LS, Manoogian ENC, Alvear A, Fleischer JG, Thor H, Dietsche K, Wang Q, Hodges JS, Esch N, Malaeb S, Harindhanavudhi T, Nair KS, Panda S, Mashek DG. Time-Restricted Eating Effects on Body Composition and Metabolic Measures in Humans who are Overweight: A Feasibility Study. Obesity (Silver Spring). 2020 May;28(5):860-869. doi: 10.1002/oby.22756. Epub 2020 Apr 9. PMID: 32270927; PMCID: PMC7180107.
- Jamshed H, Beyl RA, Della Manna DL, Yang ES, Ravussin E, Peterson CM. Early Time-Restricted Feeding Improves 24-Hour Glucose Levels and Affects Markers of the Circadian Clock, Aging, and Autophagy in Humans. Nutrients. 2019 May 30;11(6):1234. doi: 10.3390/nu11061234. PMID: 31151228; PMCID: PMC6627766.
- Gu L, Fu R, Hong J, Ni H, Yu K, Lou H. Effects of intermittent fasting in humans compared to a non-intervention diet and caloric restriction: A meta-analysis of randomized controlled trials. Frontiers in Nutrition. 2022;9.