How to Prepare for a Fast: 5 Essential Tips for Beginners

To prepare for a fast, you can start gradually reducing your portion sizes a few days before you begin. Learning how to prepare for a fast means planning your last meal, stocking up on water, choosing a fasting schedule that fits your routine, and preparing your mindset. The most beginner-friendly approach is to ease in slowly rather than stopping all food abruptly. Consulting a doctor beforehand is a good first step.

Fasting—going without food for a set period of time—is one of the oldest practices in human history. Whether the goal is spiritual, personal, or simply to build a more structured routine around eating, knowing how to prepare for a fast makes a real difference in how the experience goes. This guide to preparing for a fast is written specifically for beginners—people who want to start fasting but aren’t sure where to begin or what to expect.

Preparation is what separates a fast that feels manageable from one that falls apart by mid-morning. Without a plan, hunger pangs, low energy, and frustration tend to take over quickly. With the right steps in place—choosing a schedule, planning your last meal, managing hydration, and setting your mindset—you’ll give yourself a much better foundation for success.

This article walks you through everything you need to know, from picking the right fasting window to what to eat, what to avoid, and how to take care of yourself throughout the process. No extreme measures and no unrealistic promises—just practical, step-by-step guidance to help you get started with confidence.

A Beginner’s Guide to Intermittent Fasting Rules

If you’re new to fasting, intermittent fasting (IF) is often one of the most beginner-friendly places to start. Unlike extended fasts, intermittent fasting works by cycling between set periods of eating and not eating—it doesn’t tell you what to eat, just when to eat (1).

Before you dive into any fasting schedule, it helps to understand the core intermittent fasting rules that apply across most approaches:

• Fasting window: During the fasting period, you don’t eat. Water, plain black coffee, and unsweetened tea are generally considered acceptable, but anything with calories, including milk, juice, or sweetened drinks, typically breaks the fast. This may be slightly different in certain modified approaches.
• Eating window: This is your window for meals and snacks. You don’t need to overeat during this period; aim for balanced, nutrient-dense meals.
• Consistency matters: Keeping your fasting and eating times consistent from day to day or week to week helps your body adjust more easily over time.
• Start with shorter windows: As part of any beginner’s guide to intermittent fasting, the recommendation is almost always to start with a shorter fasting period, such as 12 hours, and only extend it once you feel comfortable.
• Listen to your body: Fasting isn’t a competition. If you feel unwell, lightheaded, or unusually fatigued, it’s reasonable to reassess your approach and speak with a doctor.
• Medical consultation first: This is particularly important if you have an underlying health condition, are taking medication, or are pregnant or breastfeeding (2).

The key mindset shift for beginners is this: intermittent fasting is a routine, not a rigid rulebook. The intermittent fasting rules listed above are general guidelines, not medical prescriptions.

Intermittent Fasting Schedules: Which One Is Right for You?

One of the first decisions you’ll make when preparing to fast is choosing a fasting schedule. Different intermittent fasting schedules suit different lifestyles, so there’s no single “best” option—only the one that fits your routine most realistically.

Here’s a breakdown of four commonly used approaches (3):

For most beginners, the 12:12 schedule is the most approachable starting point. It essentially means stopping eating after dinner and not eating again until the next morning—something many people already do naturally. Once this feels routine, you can extend it to a 14-hour fast with a 10-hour eating window (14:10), and ultimately to a 16-hour fast with an 8-hour eating window (16:8) if that aligns with your goals.

The intermittent fasting schedule for beginners that tends to work best is the one you can actually stick to consistently. Trying to jump straight into a 16:8 or more demanding schedule when you’ve never fasted before often leads to frustration. Start manageable and build from there.

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Foods to Eat Before Fasting

What you eat before your fast starts matters more than most people realize. Balanced food choices before a fast may help some people feel more comfortable during their fasting windows. The wrong ones can leave you hungry within the first couple of hours.

What to Focus on

When choosing foods to eat before fasting, prioritize:

• Protein: Eggs, lean meat, fish, tofu, legumes, and Greek yogurt all take longer to digest and contribute to a greater sense of fullness. Protein is one of the most effective nutrients for the management of hunger between meals (4).
• Fiber: Fiber-rich foods digest more slowly and may help meals feel more satisfying (5).
• Healthy fats: Avocado, nuts, seeds, and olive oil can make a meal feel more satisfying (6).
• Complex carbohydrates: Brown rice, oats, sweet potatoes, and quinoa can be part of a balanced pre-fast meal (7).

Planning Your Last Meal Before Fasting

Your last meal before fasting—sometimes that’s called a “pre-fast meal”—should be satisfying without being excessive. Overeating before a fast doesn’t make hunger disappear—it often just creates discomfort and disrupts digestion.

A well-balanced last meal before fasting might look like this:

• Grilled salmon or chicken with roasted vegetables and a side of brown rice
• Lentil soup with whole-grain bread
• A large vegetable-packed omelet with a slice of whole-grain toast and a handful of mixed nuts

You should aim to eat your last meal at a reasonable pace, without rushing. Eating slowly gives your body time to register fullness, which means you’re less likely to overeat.

Hydration counts too. Drinking water in the hours leading up to your fast and during your fasting window can support general comfort (2).

What Should You Avoid Before a Fast?

Knowing what not to do before a fast is just as useful as knowing what to eat. A few common missteps can make your first fasting experience far more uncomfortable than it needs to be.

Avoid ultra-processed foods and refined carbohydrates. Foods such as chips, white bread, sugary cereals, and packaged snacks are broken down quickly, leaving you feeling hungry again within a short time (8). These foods aren’t the best foundation for a fast.

Don’t binge eat before you start. Eating a large, heavy meal right before a fast may feel like a logical move, but it tends to cause digestive discomfort rather than prolonged fullness. A balanced, appropriately portioned meal is more useful.

Avoid jumping straight into a strict fasting window without preparation. Abruptly cutting off all food with no gradual adjustment is a common beginner’s mistake. Easing in over a few days helps your body and mind adjust far more comfortably.

Limit caffeine if you’re not used to it. Black coffee and unsweetened tea are generally fine during fasting periods, but if you don’t normally drink caffeine, starting during a fast can amplify feelings of nervousness or light-headedness. Stick to amounts you can comfortably tolerate, especially on an empty stomach.

Skip intense workouts during fasting windows. Beginners may prefer to avoid intense workouts during fasting windows, especially if they notice low energy or discomfort. It’s generally better to schedule workouts during your eating window so you have the fuel to perform and can get the nutrients you need for recovery after.

Read more: Is Fasting for 24 Hours Once a Week Healthy?

How Do I Prepare for a Fast the Day Before?

The day before your fast is one of the most important windows for preparation. You should consider these practical fasting tips for the 24 hours leading up to your start:

1. Start Winding Down Your Portions Gradually

Rather than eating a dramatically large meal the day before, aim to eat balanced, nutrient-dense meals throughout the day. This is one of the most effective tips for fasting for a day—your body adjusts more smoothly when it isn’t swinging from feast to fast.

2. Stock Up on Water and Approved Drinks

Make sure you have plenty of water on hand, along with any unsweetened teas or black coffee you plan to drink. Having drinks ready can make the fasting window easier to manage.

3. Plan Your Distractions

Hunger can feel more noticeable when your routine changes, particularly during the first few fasting attempts. Knowing that you have work, a good book, a walk, or a film lined up during peak hunger times can take the edge off significantly. Keeping busy isn’t avoiding the challenge—it’s managing it smartly.

4. Prepare Your Meals in Advance

Meal prep is an underrated fasting tip. When your eating window opens, the last thing you want is to be standing in the kitchen trying to figure out what to cook. Having a meal ready to heat and eat makes a noticeable difference.

5. Set Your Intentions

Know why you’re fasting. Whether it’s for personal structure, spiritual practice, or simply to try something new, having a clear reason helps when motivation wavers. Write it down if it helps.

How Do I Prepare for a Fast for 3 Days?

A 3-day fast is a significant undertaking and shouldn’t be attempted without guidance from a qualified healthcare professional, especially by beginners. If you’re a complete beginner, starting with an intermittent and shorter fasting window is a far more realistic and manageable approach.

If you’ve successfully completed shorter fasts and are considering a 3-day fast, here are some important guidelines:

• Eat well in the days before. Focus on nutrient-dense meals with plenty of protein, fiber, and complex carbohydrates in the 2-3 days leading up to the fast.
• Rest as much as possible. Scheduling a 3-day fast around a quiet weekend or a period with minimal physical demands makes it far more manageable.
• Do not exercise intensely. Physical exertion during a multi-day fast puts a significant additional demand on the body. Light walking or stretching is generally more appropriate.
• Speak with a doctor beforehand. Fasts that extend beyond 24 hours aren’t suitable for everyone and warrant a conversation with a qualified medical professional.

A 3-day fast may not be appropriate for people who are taking medication that requires food, are underweight, are pregnant or breastfeeding, are under 18 or over 65, or have relevant medical conditions (2).

• Consider having access to medical support during the fast. This is particularly important if this is your first extended experience.

Extended fasting isn’t for everyone, and there’s no obligation to push beyond what works for your body and lifestyle.

Read more: Intermittent Fasting Cortisol: Should You Fast?

Disclaimer: This article is intended for general informational purposes only and doesn’t address individual circumstances. It isn’t a substitute for professional medical advice, diagnosis, or treatment and shouldn’t be relied on for making decisions about your well-being. Never ignore professional medical advice in seeking treatment because of something you have read on the BetterMe Site. If you think you may have a medical emergency, immediately call your doctor or dial 911.

Frequently Asked Questions

• Is the first day of fasting the hardest?

For many beginners, yes. The first day tends to be the most challenging simply because the body and mind are adjusting to a new routine. That being said, some people find the second and third days harder as hunger cues that were initially manageable become more persistent. It often levels off once a consistent fasting routine is established.

• How much weight change can you expect on a 72-hour fast?

Short-term weight changes during a 72-hour fast may reflect shifts in water and glycogen stores rather than lasting body-fat changes. (9). However, meaningful, lasting changes in body composition typically come from consistent physical activity and a balanced nutritional approach maintained over weeks or months (10), not from a single extended fast.

• How long should I fast for digestive rest?

Fasting does not detoxify the body in the way that is often claimed. The liver, kidneys, lungs, skin, and digestive system are already responsible for processing and clearing waste continuously (11). Fasting isn’t necessary for the body to process and clear waste. If you have specific questions about digestive well-being, speaking with a doctor is the most reliable step.

• What electrolytes do I need when fasting?

Electrolytes, including sodium, potassium, chloride, magnesium, calcium, phosphate, and bicarbonates, play a role in fluid balance, muscle function, and many other processes in the body (12). During a fast, electrolyte levels can shift. Drinking water throughout the fasting window helps, and when your eating window opens, prioritizing foods that naturally contain these minerals (leafy greens, nuts, seeds, legumes, dairy or dairy alternatives) is a practical way to support your levels. For longer fasts, talk to your healthcare provider about whether you may need to add electrolytes to your water and which ones.

• How should a beginner start fasting?

Begin with a 12-hour fasting window (12:12)—for example, finishing dinner by 8 pm and eating breakfast again at 8 am. Once this routine feels comfortable, gradually extend your fasting window. Keeping your eating and fasting times consistent, staying hydrated, and planning meals in advance are the most practical starting points.

The Bottom Line

Preparing for a fast is less about willpower and more about planning. When you know how to prepare for a fast—choosing the right schedule, eating a balanced last meal, staying hydrated, managing your mindset, and knowing what to avoid—the experience becomes far more manageable, especially for beginners.

Start with a beginner-friendly schedule such as 12:12, give yourself a few days to ease in, and be realistic about what your body needs. Fasting isn’t one-size-fits-all, and there’s no pressure to jump to the most demanding version right away.

If you’re unsure whether fasting is appropriate for your specific situation, it could be worthwhile to speak to a doctor before you make changes to your eating routine. BetterMe offers structured meal plans and fasting trackers to help you build a consistent routine—explore the tools available to support your journey.