What to Eat During Your Eating Window

Quick answer: Focus on protein (at least 1.6g per kg of body weight daily), healthy fats, complex carbohydrates, and fiber-rich vegetables. The quality of what you eat during your window determines whether intermittent fasting delivers real results or just shifts your meal times around.

Intermittent fasting tells you when to eat. But it says nothing about what to eat, and that gap trips up a lot of people. Some assume the fasting hours do all the work. Others overcorrect and eat too little, sabotaging their energy and muscle mass. The truth is in the middle: your eating window is a limited opportunity to nourish your body well, and it pays to be strategic about it.

Why Food Quality Matters More With IF

When you compress your eating into 6-8 hours, you have fewer meals to get your nutrition right. Miss the mark and the consequences show up faster than they would on a normal schedule. Skimp on protein and you lose muscle. Skip fiber and you get constipated. Eat nothing but refined carbs and you will crash hard before your next fast even starts.

A 2020 trial published in JAMA Internal Medicine found that time-restricted eating without attention to diet quality produced no significant weight loss advantage over normal eating (Lowe et al., 2020). The participants lost weight, but they also lost lean mass, which is the opposite of what you want. The lesson: IF is a framework, not a magic trick. What fills the frame matters enormously.

Breaking Your Fast: The First Meal

Your first meal after a fast sets the tone for your entire eating window. After 16 or more hours without food, your digestive system is primed and your insulin sensitivity is at its peak. This is both an opportunity and a caution.

What works well as a fast-breaking meal:

Eggs with avocado and sauteed greens
Greek yogurt with nuts and berries
Grilled chicken salad with olive oil dressing
A smoothie with protein powder, spinach, nut butter, and berries

What to avoid:

Large amounts of sugar or refined carbs (causes a sharp insulin spike and crash)
Heavy fried foods (can cause digestive discomfort after extended fasting)
Massive portions (your stomach has been empty; ease back in)

For a deeper look at optimizing that first meal, check our guide on the best foods to break your fast.

Macronutrient Priorities

Protein: The Non-Negotiable

Protein is the single most important macronutrient during your eating window. It preserves lean muscle mass, increases satiety, and has the highest thermic effect of food, meaning your body burns more calories digesting it.

A position paper by the International Society of Sports Nutrition recommends 1.6-2.2 grams of protein per kilogram of body weight daily for active individuals (Jager et al., Journal of the International Society of Sports Nutrition, 2017). Even sedentary fasters should aim for at least 1.2-1.6 g/kg to prevent muscle loss.

For a 70 kg person, that means 112-154 grams of protein daily, spread across your 2-3 meals. This requires intentional planning.

High-quality protein sources:

Chicken breast (31g per 100g)
Salmon (25g per 100g)
Eggs (6g each)
Greek yogurt (10g per 100g)
Lentils (9g per 100g cooked)
Cottage cheese (11g per 100g)
Tofu (8g per 100g)
Whey protein (20-25g per scoop)

Healthy Fats: Satiety and Hormones

Fat keeps you full, supports hormone production, and helps absorb fat-soluble vitamins. It is especially important for fasters because the prolonged satiety it provides makes your next fasting period easier to endure.

A study in Appetite (2018) found that meals higher in monounsaturated fats increased post-meal satiety scores significantly compared to low-fat meals, with effects lasting 4-5 hours (Stevenson et al., 2018).

Best fat sources:

Extra virgin olive oil
Avocados
Nuts and seeds (almonds, walnuts, chia seeds, flaxseeds)
Fatty fish (salmon, mackerel, sardines)
Eggs (whole, not just whites)

Complex Carbohydrates: Sustained Energy

Carbs are not the enemy, but the type matters. Complex carbohydrates provide sustained energy and fiber, while refined carbs cause blood sugar spikes that leave you hungry and irritable during your fast.

Choose these:

Sweet potatoes
Brown rice and quinoa
Oats (steel-cut or rolled)
Legumes (lentils, chickpeas, black beans)
Whole grain bread (true whole grain, not "wheat" bread)
All vegetables

Limit these:

White bread and pasta
Sugary cereals
Pastries and baked goods
Candy and sweets
Fruit juice

Fiber: The Underrated Hero

Fiber supports digestive health, feeds your gut microbiome, and significantly improves satiety. A 2019 meta-analysis in The Lancet found that people consuming 25-29 grams of fiber daily had a 15-30% reduction in all-cause mortality compared to low-fiber eaters (Reynolds et al., 2019).

During intermittent fasting, fiber is especially valuable because it slows gastric emptying, keeping you full longer as you enter your fasting window.

High-fiber foods:

Lentils (15g per cup cooked)
Black beans (15g per cup)
Avocado (10g per avocado)
Broccoli (5g per cup)
Chia seeds (10g per 2 tablespoons)
Raspberries (8g per cup)

For a comprehensive list, see our guide on the best foods for intermittent fasting.

Sample Meals for a 16:8 Window (Noon to 8 PM)

Meal 1 (12:00 PM) - Break the Fast

Scrambled eggs (3) with spinach and feta cheese, half an avocado, and a slice of whole grain toast. Side of mixed berries.

Approximately: 550 calories, 35g protein, 30g fat, 35g carbs, 10g fiber

Meal 2 (3:30 PM) - Midday Meal

Grilled chicken thigh over a large mixed green salad with olive oil and lemon dressing, cherry tomatoes, cucumber, chickpeas, and pumpkin seeds.

Approximately: 600 calories, 45g protein, 28g fat, 30g carbs, 8g fiber

Meal 3 (7:30 PM) - Final Meal

Baked salmon with roasted sweet potato and steamed broccoli. Small handful of dark chocolate (85%+) for dessert.

Approximately: 650 calories, 40g protein, 28g fat, 50g carbs, 9g fiber

Daily totals: ~1,800 calories, ~120g protein, ~86g fat, ~115g carbs, ~27g fiber

Adjust portions up or down based on your caloric needs, activity level, and goals. If you want a full week of structured meals, check our 7-day intermittent fasting meal plan.

Hydration During Your Eating Window

Most people focus on hydrating during the fast but forget about their eating window. You should be drinking water throughout the day, not just during fasting hours.

A reasonable target is 2.5-3.5 liters daily, more if you exercise or live in a hot climate. Signs of dehydration that fasters commonly mistake for hunger include headaches, fatigue, and difficulty concentrating.

During your eating window, water-rich foods also count: cucumbers, watermelon, lettuce, tomatoes, and soups.

Foods That Make Fasting Easier

Some foods are particularly helpful to eat at the end of your window because they sustain you longer into the fast:

Casein-rich dairy (cottage cheese, Greek yogurt): Casein digests slowly, providing a steady amino acid release over hours.
Eggs: High in fat and protein with excellent satiety scores.
Nuts and nut butters: Calorie-dense and slow-digesting.
Avocado: The combination of fiber and fat creates lasting fullness.
Oily fish: Omega-3 fatty acids and protein in one package.

Eating these at your last meal can meaningfully reduce morning hunger during your fast.

Foods That Sabotage Your Results

Certain foods undermine intermittent fasting even when eaten within your window:

Ultra-processed foods: A landmark 2019 NIH study found that people eating ultra-processed diets consumed an average of 500 extra calories per day compared to those eating whole foods, even when meals were matched for macronutrients (Hall et al., Cell Metabolism, 2019).
Sugary drinks: Liquid calories bypass satiety signals. A single soda can add 150+ empty calories.
Alcohol: Beyond the empty calories, alcohol disrupts sleep quality and impairs next-day fasting adherence. It also inhibits fat oxidation for hours after consumption.
Refined snack foods: Chips, crackers, and cookies offer little nutrition and trigger overeating.

This does not mean you can never have a treat. But if these foods dominate your eating window, IF will not deliver the results you are looking for.

Special Considerations

Vegetarian and Vegan Fasters

Getting adequate protein on plant-based diets requires more planning. Combine legumes, tofu, tempeh, seitan, and plant-based protein powders across your meals. A 2021 review in Sports Medicine confirmed that plant protein can support muscle maintenance as effectively as animal protein when total intake is sufficient (Hevia-Larrain et al., 2021).

Athletes and Active People

If you train intensely, you may need to time your eating window around workouts and increase total protein intake to 2.0-2.2 g/kg. Post-workout nutrition within your eating window should prioritize fast-digesting protein and carbohydrates for recovery.

People Over 50

Older adults have higher protein needs (at least 1.2 g/kg) due to anabolic resistance, a reduced ability to build muscle from the same amount of protein. Prioritize protein at every meal and consider supplementing with leucine-rich sources like whey or eggs.

How Fasted Helps

Fasted's meal logging feature lets you record what you eat during your window, so you can see patterns over time, not just when you fasted but how you fueled. Combined with weight tracking and fasting streaks, you get a complete picture of what is driving your results. The app helps you connect the dots between your food choices and your progress.

Frequently Asked Questions

Can I eat whatever I want during my eating window?

Technically, yes. Practically, no. IF creates a caloric deficit for most people naturally, but poor food choices can negate this advantage and leave you malnourished. Focus on whole, nutrient-dense foods for best results.

How many meals should I eat during my window?

Two to three meals works for most people on a 16:8 schedule. Some people prefer two larger meals, others add a small snack. The key is meeting your protein and calorie targets without forcing meals.

Should I eat differently on workout days?

If you exercise regularly, consider adding extra carbohydrates and protein around your training sessions. On rest days, you can reduce carbs slightly and rely more on fats and protein.

Is it normal to feel very hungry during my eating window?

Some hunger is normal, but ravenous, uncontrollable hunger usually signals that your meals lack protein, fat, or fiber. Increase these macronutrients and the excessive hunger should subside within a few days.

Do I need to take supplements during intermittent fasting?

A well-planned diet covers most needs, but a few supplements are worth considering: vitamin D (especially in winter), omega-3s (if you do not eat fatty fish regularly), and magnesium (commonly deficient). Take fat-soluble supplements with a meal containing fat.