Intermittent fasting (IF) is an eating pattern that alternates between periods of fasting and eating. IF does not focus on what food to eat but when you eat. Research shows fasting for a certain number of hours each day or reducing how often we eat throughout the week may bring about health benefits. [1,2]
There are several ways to practice intermittent fasting. Here are some of the most common methods:
1. Time-Restricted Eating
- 16:8 Method (Leangains Diet) – Features a daily 16-hour fast and a 8-hour eating window. One of the most popular and manageable IF methods.
- 5:2 Method (The Fast Diet) – Involves eating like normal on 5 days of the week and restricting calorie intake to 500 to 600 on the remaining 2 days.
- Fasting for 12 hours a day – You fast for 12 hours and eat within the remaining 12 hours each day. Easiest for beginners as sleep time is included in the fasting period
2. Eat Stop Eat
This method involves a complete 24-hour fast once or twice a week. During the fasting period, water, black coffee and other calorie-free drinks are allowed. However, a full-day 24-hour fast can be difficult and may lead to fatigue or headaches.
3. Alternate Day Fasting
This method involves alternating between days of normal eating and days of fasting. It is an extreme form of intermittent fasting and may not be suitable for beginners or those with certain medical conditions. It is also more difficult to maintain long term.
4. The Warrior Diet
This diet involves eating small amounts of raw fruits and vegetables during the day and eating one large meal at night within a 4 hours of eating window. It is best for people who have tried other forms of intermittent fasting [3,4]
How does it work?
When you go without food for several hours, your body shifts into a different mode. It starts to burn stored fat for energy.
During this fasting period, several helpful changes happen:
- More fat burning: Human growth hormone (HGH) levels rise, thus your body uses fat while preserving muscle.
- Better blood sugar control: Insulin levels drop, making it easier to access stored fat.
- Cell Repair: Your cells repair themselves and remove damaged parts.
- Healthier genes: Certain genes linked to longevity and disease protection become more active.
In simple terms, intermittent fasting gives your body a break from digestion as it focuses on burning fat, repairing cells and supporting long-term health. [1, 2, 5]
Is Intermittent Fasting Right for You?
Intermittent fasting isn’t suitable for everyone. Remember to check with a doctor, dietitian or your primary care provider before starting.
You should avoid intermittent fasting if you are:
- Under 18 years old
- Diagnosed with certain chronic illnesses or eating disorders
- Living with hypoglycemia
- Pregnant or breastfeeding
- Malnourished
For those doing intermittent fasting, you should always take nutrient-dense meals, prioritize hydration and manage portion sizes to avoid overeating. However, do be aware that intermittent fasting may come with certain side effects. For example:
- Irritability
- Low energy levels
- Persistent hunger
- Sensitivity to temperature changes
- Poor performance in work or physical activities
Remember there is no one size fits all approach. The best eating pattern is one that supports your health, fits your lifestyle and makes you feel your best. Your health and well-being should always come first. [2,6]
References
- Gunnars, K. (2020, April 21). Intermittent Fasting 101 — The Ultimate Beginner’s Guide. Healthline.
- Johns Hopkins Medicine. (2021). Intermittent fasting: What is it, and how does it work? JohnsHopkinsMedicine.
- Gunnars, K. (2020, January 1). 6 popular ways to do intermittent fasting. Healthline.
- Leonard, J. (2020, April 16). 6 ways to do intermittent fasting. Medicalnewstoday.com; MedicalNewsToday.
- Mundi, M. (2022, May 5). What is intermittent fasting? Does it have health benefits? MayoClinic.
- Cleveland Clinic. (2022, March 2). Intermittent fasting: How it works and 4 types explained.ClevelandClinic.
