Intermittent Fasting for Beginners: How to Start 16:8

To start intermittent fasting for beginners, adopt the 16:8 method by fasting for 16 hours overnight and consuming all your calories within an 8-hour daytime window. Begin by simply skipping breakfast, staying hydrated with water or black coffee, and prioritizing protein during your eating window to maintain steady energy.

Key takeaways

Start simple: The 16:8 method is the most sustainable schedule because you spend the majority of your fasting time asleep.
Hydration is critical: Thirst often masquerades as hunger. Drinking adequate water, black coffee, or herbal tea during your fasting window is essential for success.
How you break the fast matters: Ending your fast with a high-sugar meal will cause an insulin spike and a subsequent energy crash. Always break your fast with lean protein and healthy fats.
Tools help build habits: Using a dedicated, distraction-free app can remove the mental friction of calculating your fasting and eating windows every day.

What is intermittent fasting? Intermittent fasting is a dietary pattern that cycles between voluntary periods of eating and abstaining from food, focusing on meal timing rather than restricting specific food groups.

What is the 16:8 method? The 16:8 method is a time-restricted eating schedule where you consume all of your daily calories within a continuous 8-hour window and abstain from calories for the remaining 16 hours.

Why 16:8 is the gold standard for beginners

When you first explore intermittent fasting for beginners, the sheer number of protocols can be overwhelming. You will encounter the 5:2 diet, alternate-day fasting, the Warrior Diet (20:4), and even 24-hour fasts (Eat-Stop-Eat).

While all of these methods have their place in advanced metabolic conditioning, the 16:8 schedule remains the absolute gold standard for beginners. Major health organizations, including guidance published by sources like Healthline and Dietitians Australia, frequently highlight the 16:8 method due to its high compliance rate and safety profile.

The brilliance of the 16:8 method lies in its alignment with your natural circadian rhythm. Because you are already fasting while you sleep, a 16-hour fast typically only requires you to skip one meal—usually breakfast or a late-night snack. It does not require extreme calorie restriction or agonizing days without food. It simply requires a slight restructuring of your existing routine. By establishing an 8-hour eating block, you naturally eliminate late-night snacking, which is a major contributor to unwanted weight gain and poor sleep quality.

The science: What happens during those 16 hours?

Intermittent fasting is not magic; it is biology. When you eat a standard diet consisting of three meals and snacks scattered throughout the day, your body runs primarily on glucose (sugar) from your food. Your insulin levels remain elevated, instructing your body to store excess energy as fat.

When you stop eating for an extended period, your body is forced to shift its fuel source.

By hour 12 of your fast, your body has typically depleted the glycogen (stored sugar) in your liver. Because it still needs energy, it begins to break down stored body fat into molecules called ketones to use as fuel. This metabolic switch from burning sugar to burning fat is the primary driver of weight loss in intermittent fasting.

Furthermore, pushing your fast toward the 16-hour mark initiates a mild state of autophagy. Autophagy is a cellular cleanup process where your body clears out damaged cells and regenerates new, healthy ones.

If you want a deeper understanding of these biological milestones, read our comprehensive timeline in The Stages of a Fast: What Happens in Your Body Hour by Hour.

Step-by-Step: How to start your first fast

Starting a new health habit requires a plan. If you wake up and simply decide, "I'm not going to eat today," you will likely fail by 10:00 AM. Here is a structured approach to beginning your 16:8 practice.

Step 1: Choose your 8-hour eating window

Your fasting schedule must fit your lifestyle, not the other way around. The most common and socially adaptable window is 12:00 PM to 8:00 PM. This allows you to skip breakfast, eat a normal lunch with colleagues, and enjoy dinner with your family.

However, if you are an early riser who cannot function without a morning meal, you might prefer an early eating window.

Popular 16:8 Fasting Schedules

Schedule Name	Fasting Window	Eating Window	Best For
The Lunch & Dinner	8:00 PM – 12:00 PM	12:00 PM – 8:00 PM	Most people; skipping breakfast
The Early Bird	4:00 PM – 8:00 AM	8:00 AM – 4:00 PM	Morning workout enthusiasts
The Graveyard Shift	8:00 AM – 12:00 AM	12:00 AM – 8:00 AM	Night shift workers

Note: Choose one schedule and stick to it for at least a week to allow your body's hunger hormones (like ghrelin) to adjust.

Step 2: Prepare your fasting fluids

During your 16-hour fasting window, you cannot consume any calories. Doing so will spike your insulin and "break" the fast, stopping the fat-burning process. However, staying hydrated is absolutely critical. Mild dehydration often presents as acute hunger.

What you CAN consume during the fast:

Water: Flat, sparkling, or mineral water. You can add a pinch of sea salt to replenish electrolytes.
Black Coffee: Plain black coffee contains practically zero calories. It also acts as an appetite suppressant and can mildly boost your metabolic rate.
Plain Tea: Green tea, black tea, or herbal teas are acceptable, provided nothing is added to them.

What you CANNOT consume during the fast:

Sugar, honey, or artificial sweeteners (some sweeteners can trigger an insulin response even without calories).
Milk, cream, or oat milk in your coffee.
Bone broth (this contains protein and calories, which breaks the fasting state, even though it is popular in some prolonged fasting circles).

Step 3: Break your fast the right way

The first meal you eat after a 16-hour fast is the most important meal of the day. Your digestive system has been resting, and your insulin levels are very low.

If you break your fast with a heavy carbohydrate meal—like a large bowl of pasta or a sugary pastry—your blood sugar will skyrocket. This massive insulin spike will inevitably be followed by a sharp crash, leaving you feeling lethargic, bloated, and intensely hungry just a few hours later.

Instead, ease your digestive system back to work. Break your fast with a meal anchored in lean protein, healthy fats, and fiber.

Excellent "break-fast" options:

A three-egg omelet with spinach and avocado.
A piece of grilled chicken or salmon over a large leafy green salad with olive oil dressing.
A bowl of plain Greek yogurt with a handful of almonds and chia seeds.

What to eat during your window

Intermittent fasting is a rule about when you eat, not what you eat. However, cramming 4,000 calories of ultra-processed food into an 8-hour window will negate any health benefits of the fast.

During your eating window, you should consume your normal daily caloric intake, aiming for nutrient density. The Mediterranean Diet model—emphasizing whole grains, lean proteins, vegetables, and healthy fats (like olive oil and avocados)—is widely recommended by institutions like WebMD as an ideal companion to intermittent fasting.

Try to space your meals out. Eating two large meals and one small snack within the 8 hours provides sustained energy and prevents the uncomfortable feeling of being overly full.

Managing hunger and side effects

When you first begin the 16:8 method, your body will rebel slightly. For years, you have conditioned your stomach to expect food at specific times. The hormone ghrelin, which signals hunger, operates on a circadian rhythm based on your past eating habits.

During the first 3 to 7 days, you will experience hunger waves. The key word is waves. Hunger is not a straight line that constantly gets worse; it crests and then subsides. When you feel a hunger wave hit at 10:00 AM, drink a large glass of water or a cup of black coffee, and wait 15 minutes. It will pass.

Other common initial side effects include mild headaches or slight irritability. These are often caused by dehydration and the loss of electrolytes as your body depletes its glycogen stores. Adding a small pinch of high-quality salt to your water can mitigate these symptoms.

Using technology to stay on track

One of the biggest hurdles for beginners is the mental math. Remembering exactly when you finished your last bite of dinner and calculating when you are "allowed" to eat lunch the next day introduces unnecessary friction.

This is exactly why we built Orbit. Orbit is our app; we built and use it specifically to remove this mental load. It provides a simple, beautiful, iOS-native timer that tells you exactly where you are in your fast and tracks your physiological milestones. It is designed to be a quiet companion in the background of your life, not a noisy distraction.

If you are just starting out, we highly recommend utilizing a clean digital timer to build your consistency.

To see our recommendations for other excellent tracking tools available, including entirely unpaid options, check out our guide to The Best Free Intermittent Fasting Apps for iPhone. You can also see how we compare to the industry giants in our The Best Intermittent Fasting Apps in 2026 roundup.

Disclaimer

Disclaimer: The information provided in this article is for educational and informational purposes only and is not intended as medical advice. Intermittent fasting is not suitable for everyone. Please consult a qualified healthcare professional before beginning any fasting regimen, especially if you are pregnant, nursing, have diabetes, or have a history of disordered eating.

Frequently asked questions

Can I drink coffee with milk during a fast?

No. Adding milk, cream, or alternative milks (like oat or almond milk) introduces calories and macronutrients that will trigger an insulin response and break your fast. You must stick to plain black coffee during the fasting window. For a full breakdown of what you can and can't drink, see Does Coffee Break a Fast?

What if I work out in the morning?

Working out in a fasted state is highly effective for fat burning. However, if you perform high-intensity workouts and feel dizzy, you may need to shift your 8-hour eating window earlier (e.g., 8:00 AM to 4:00 PM) so you can consume protein shortly after your workout to aid recovery.

Will 16:8 intermittent fasting slow down my metabolism?

No. Unlike chronic daily calorie restriction, which can depress your basal metabolic rate over time, short-term fasting has been shown to temporarily boost metabolism due to an increase in norepinephrine levels, which helps mobilize body fat for energy.

What should I do if I feel dizzy or faint while fasting?

If you feel dizzy, excessively weak, or faint, you should break your fast immediately with a small, balanced snack. Safety always comes first. Ensure you are drinking enough water and electrolytes. If the problem persists, consult a doctor.

Can I change my fasting hours on the weekends?

Yes. The 16:8 schedule is flexible. If you normally fast from 8:00 PM to 12:00 PM during the week, but have a late dinner scheduled for Saturday night, you can simply adjust your window to fast from 10:00 PM to 2:00 PM the next day. Consistency is important, but rigid perfection is not necessary.