What Should I Eat on Alternate Day Fasting for Optimal Results?

October 16, 2025 •

5 min read

According to a 2022 meta-analysis in Obesity, alternate day fasting (ADF) was shown to be a superior weight loss strategy compared to other intermittent fasting methods. To achieve these kinds of results, it's crucial to know what should I eat on alternate day fasting on both restricted and unrestricted days to stay nourished and prevent muscle loss.

Quick Summary

This article details optimal food choices for alternate day fasting (ADF), distinguishing between modified fasting days (around 500-600 calories) and non-fasting days. It outlines nutrient-dense, high-protein, and high-fiber foods to prioritize, along with meal strategies for managing hunger and maximizing health benefits on this eating plan.

Key Points

Fasting Day Focus: On modified fasting days (around 500-600 calories), prioritize lean proteins, high-fiber vegetables, and healthy fats to maximize satiety and nutrient intake.
Non-Fasting Day Strategy: On non-fasting days, eat a balanced diet of whole foods, including lean proteins, healthy fats, complex carbs, and plenty of fruits and vegetables, to replenish and nourish your body.
Stay Hydrated: Drink plenty of water and other calorie-free beverages like black coffee and herbal tea throughout both fasting and non-fasting days to manage hunger and stay hydrated.
Prevent Compensatory Eating: Avoid the temptation to overeat or binge on non-fasting days. Focus on mindful eating and nutrient-dense foods to sustain momentum and health benefits.
Prioritize Nutrient Density: For both fasting and feasting days, choose foods that pack the most nutritional punch per calorie to ensure you get essential vitamins and minerals.
Consult a Professional: Always talk to a doctor or registered dietitian before beginning alternate day fasting, especially if you have underlying health issues.

Alternate day fasting (ADF) is a popular intermittent fasting strategy that involves alternating between days of minimal caloric intake and days of eating normally. The most common approach, modified ADF, limits calories to about 500-600 on 'fasting' days while allowing for unrestricted eating on 'non-fasting' days. Strategic food choices on both types of days are key to success, ensuring you meet nutritional needs, manage hunger, and support your health goals. But what should I eat on alternate day fasting to maximize fat loss and well-being?

Fasting Day Food Strategy (500-600 Calories)

On a modified fasting day, your goal is to consume highly nutritious foods that maximize satiety despite the limited calorie budget. Opt for foods rich in protein, fiber, and healthy fats, which help you feel full and satisfied longer. Hydration is also paramount, so calorie-free liquids are your best friend.

Recommended Foods for Fasting Days

Lean Protein: Small portions of grilled chicken, fish, eggs, or tofu provide essential amino acids and a high-satiety factor.
High-Fiber Vegetables: Load up on non-starchy vegetables like leafy greens (spinach, kale), broccoli, and cauliflower. These offer volume and nutrients with very few calories.
Greek Yogurt: A small portion of plain Greek yogurt with berries can provide protein and a touch of sweetness while keeping calories low.
Broth-Based Soups: Vegetable or bone broth soups can be very filling and hydrating, helping to curb hunger.
Healthy Fats (in moderation): A few nuts, seeds, or a small slice of avocado can add richness and satiety within your calorie limit.
Calorie-Free Drinks: Water is essential. You can also have black coffee or unsweetened herbal tea to help curb hunger.

Non-Fasting Day Food Strategy (Unrestricted Eating)

While non-fasting days allow you to eat normally, this is not a free pass for bingeing on junk food. The quality of your food still matters for long-term health and weight management. Prioritizing whole, nutrient-dense foods will help sustain energy levels and provide the vitamins and minerals your body needs.

Key Foods for Non-Fasting Days

High-Quality Protein: Continue to include lean meats, fish, poultry, eggs, and plant-based protein sources like lentils and beans.
Healthy Fats: Incorporate healthy fats from avocados, olive oil, nuts, and seeds. These support cellular function and hormone balance.
Complex Carbohydrates: Fuel your body with complex carbs from whole grains (quinoa, oats, brown rice) and starchy vegetables (sweet potatoes).
Plenty of Fiber: Fill your plate with fruits and a wide variety of vegetables to ensure adequate fiber intake, which supports digestion and overall health.

Comparison of Food Choices: Fasting vs. Non-Fasting Days


Feature	Fasting Day	Non-Fasting Day
Calorie Intake	~500-600 calories	Unrestricted, but focus on quality
Protein	Small portions of lean sources (e.g., eggs, tofu, grilled fish)	Larger, varied sources (e.g., salmon, chicken breast, lentils)
Carbohydrates	Minimal, from non-starchy vegetables and berries	Complex carbs from whole grains, fruits, and starchy vegetables
Fats	Very limited, a few nuts or a slice of avocado	Healthy fats from avocados, nuts, seeds, olive oil
Beverages	Water, black coffee, herbal tea	Water, herbal teas, coffee (can add milk/sugar), fresh juices
Focus	Satiety and nutrient density within calorie limits	Balanced, nutrient-rich meals to replenish and fuel

Sample Meal Plan for ADF

Fasting Day:

Breakfast (Optional): Black coffee or herbal tea.
Lunch (250 calories): Two scrambled eggs with a large handful of spinach.
Dinner (250 calories): A cup of vegetable soup with a small grilled fish fillet.
Throughout the day: Plenty of water and optional unsweetened tea.

Non-Fasting Day:

Breakfast: Oatmeal with fresh berries, nuts, and a spoonful of Greek yogurt.
Lunch: A large mixed green salad with grilled chicken breast, avocado, cherry tomatoes, and a vinaigrette dressing.
Snack: Apple slices with a tablespoon of almond butter.
Dinner: Baked salmon with roasted sweet potatoes and steamed asparagus.

How to Succeed with Alternate Day Fasting

Listen to Your Body: Pay attention to hunger cues on non-fasting days, and don't force-feed yourself if you are not hungry. Conversely, recognize that initial fasting days will require mental fortitude, and it's okay to start with a less restrictive modified ADF.
Plan Ahead: Knowing what you will eat on both fasting and non-fasting days can prevent impulsive, unhealthy choices, especially after a period of restriction. Meal prepping can be very helpful.
Stay Hydrated: Drinking plenty of water is essential on both fasting and non-fasting days. It can help manage hunger and prevent fatigue. Adding electrolytes to your water on fasting days can also be beneficial.
Prioritize Protein and Fiber: On your fasting days, focus on these two macronutrients to help keep you full. On your eating days, they will support muscle maintenance and sustained energy.
Be Mindful of Nutrient Deficiencies: While non-fasting days are unrestricted, it's important to eat a variety of whole foods to ensure you get all necessary vitamins and minerals.
Avoid Compensatory Eating: The temptation to overeat on non-fasting days can be strong. While studies suggest this is not a significant long-term issue for most, mindful eating helps maintain results and prevents digestive discomfort.

Conclusion

For those asking what should I eat on alternate day fasting, the answer depends on whether it's a fasting or non-fasting day. On restricted days, the focus is on low-calorie, nutrient-dense foods like lean protein, fiber-rich vegetables, and calorie-free liquids to manage hunger effectively. On unrestricted days, a balanced, whole-food diet is recommended to replenish nutrients and support overall health, avoiding the pitfall of overindulgence. By following a thoughtful approach to nutrition on both types of days, individuals can maximize the benefits of ADF, including weight loss and improved metabolic health. Always consult with a healthcare provider before beginning any new diet, especially if you have underlying health conditions.

Important Note: This article provides general dietary guidance and is not a substitute for professional medical advice. Individuals should consult with a healthcare professional or registered dietitian before starting any new diet, especially alternate day fasting.

Disclaimer:

This article is for informational purposes only. It is not intended to provide medical advice, diagnose, or treat any health condition. The content is based on research and general dietary principles related to alternate day fasting. Individual results and experiences may vary. Always seek the advice of a qualified health provider for any questions regarding a medical condition or dietary changes.

Frequently Asked Questions

While technically you can eat without restriction on non-fasting days, it's best to focus on balanced, nutrient-dense meals with lean protein, healthy fats, whole grains, and plenty of fruits and vegetables. Eating junk food can undo the benefits of fasting.

On a fasting day, you could have scrambled eggs with spinach (250 kcal) for one meal, and a broth-based vegetable soup with a small piece of grilled fish (250 kcal) for another. Lean protein and vegetables are key for satiety.

ADF, when done correctly with adequate protein on eating days, has been shown to be effective for fat loss while preserving lean muscle mass. High-protein, nutrient-dense meals on eating days are critical for this.

On fasting days, stick to zero-calorie beverages such as water, black coffee, and unsweetened herbal tea. These can help manage hunger without breaking your fast. Some people also use electrolyte water (without sugar).

Yes, moderate exercise can be safely combined with ADF, though it's important to listen to your body. Some studies suggest combining ADF with endurance exercise can significantly increase weight loss. Always consult a doctor before starting a new exercise regimen.

Hunger can be managed by drinking plenty of water, staying busy with activities, and eating nutrient-dense, high-fiber foods if following a modified fast. Over time, many people find their hunger diminishes as their body adapts.

Research suggests that for weight loss, ADF can be just as effective as daily calorie restriction. Some find ADF easier to adhere to because of the less restrictive eating days, while others prefer the consistency of daily calorie counting.

Studies have shown that ADF can be effective with both high-fat and low-fat diets, but focusing on healthy fats is always recommended. Some people, particularly those on ketogenic diets, find that consuming more healthy fats helps with satiety.