What is intermittent fasting?

How does intermittent fasting work?

When you eat, your body spends several hours processing and burning what you consumed. During this fed state, it is difficult for your body to burn fat because insulin levels are high. After 8-12 hours without food, your body enters a fasted state where insulin levels drop, making stored fat more accessible as energy.

This metabolic shift is why intermittent fasting helps with weight loss even without counting calories. Your body naturally transitions through several distinct phases during a fast:

• Fed state (0-2 hours): Your body digests and absorbs nutrients. Insulin rises.
• Early fasting (2-6 hours): Insulin begins to fall. Your body starts using stored glycogen.
• Glycogen depletion (6-10 hours): Liver glycogen stores are being used up.
• Metabolic switch (10-14 hours): Your body switches from glucose to fat as its primary fuel source.
• Fat burning (14-18 hours): Active fat oxidation. This is where most weight loss happens.
• Deep ketosis (18-24 hours): Elevated ketone production. Enhanced mental clarity for many people.
• Autophagy (24-48 hours): Cellular cleanup and renewal processes accelerate.

Popular intermittent fasting methods

There are several approaches to intermittent fasting. The best method is the one you can follow consistently.

• 16:8 method: Fast for 16 hours, eat within an 8-hour window. The most popular and well-researched protocol.
• 14:10 method: A gentler version with a 14-hour fast and 10-hour eating window. Great for beginners.
• 18:6 method: An intermediate protocol with 18 hours of fasting and a 6-hour eating window.
• 20:4 (Warrior Diet): Advanced protocol with a 4-hour eating window.
• OMAD (One Meal a Day): You eat all daily calories in a single meal.
• 5:2 method: Eat normally 5 days per week, restrict calories to 500-600 on 2 non-consecutive days.

Proven health benefits

Intermittent fasting is backed by extensive research showing benefits beyond weight loss:

• Weight loss: Studies show IF leads to 3-8% weight loss over 3-24 weeks, with significant reduction in belly fat.
• Insulin sensitivity: Fasting reduces fasting insulin by 20-31%, helping protect against type 2 diabetes.
• Inflammation: Studies show reductions in markers of inflammation, a key driver of chronic disease.
• Heart health: IF may reduce LDL cholesterol, blood triglycerides, and blood pressure.
• Brain health: Fasting increases production of brain-derived neurotrophic factor (BDNF), which supports learning and memory.
• Cellular repair: Fasting triggers autophagy, a process where cells remove damaged components and regenerate.

How to start intermittent fasting

Getting started is simpler than you think:

1. Choose a gentle protocol. Start with 12:12 or 14:10. You are probably already fasting 10-11 hours overnight.
2. Pick your eating window. Most people skip breakfast and eat from noon to 8pm, but choose what fits your schedule.
3. Stay hydrated. Drink water, black coffee, and plain tea during fasting hours.
4. Track your fasts. Use an app like FastBreak to build consistency and see your progress.
5. Gradually extend. Once 14:10 feels easy, try 16:8. Let your body adapt at its own pace.

Who should avoid intermittent fasting?

Intermittent fasting is not appropriate for everyone. Do not fast if you are:

• Pregnant or breastfeeding
• Under 18 years old
• Living with an eating disorder (current or history)
• Managing type 1 diabetes
• Taking medications that require food intake
• Underweight (BMI below 18.5)

Always consult your healthcare provider before starting any fasting regimen.