21 Foods to Avoid While Intermittent Fasting (2025)

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Tim Brennan

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foods to avoid while intermittent fasting

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If you are looking for foods to avoid while intermittent fasting, this giant food list of what not to eat will have you covered.

Managing Intermittent Fasting Through Diet

Intermittent fasting works best when you keep insulin low during fasting hours and break your fast with simple, gentle foods. I’ve experimented with multiple intermittent fasting schedules, and the biggest game-changer was learning which foods and drinks quietly derail progress.

Sugary beverages, “healthy” snacks with hidden syrups, and heavy creamers can sabotage fat-burning and trigger cravings. Dialing in foods to avoid while intermittent fasting-and what to keep on hand-makes the routine easier, steadier, and more sustainable.

According to Healthline, “intermittent fasting can cause weight loss, reduce inflammation, improve heart health, and may even extend lifespan.” That’s why it’s so important to know the foods to avoid while intermittent fasting, so you protect your health benefits and long-term results.

What Is Intermittent Fasting?

Intermittent fasting cycles periods of fasting with defined eating windows. Popular approaches include the 16:8 method, alternate-day fasting, and time-restricted eating. During the fasting window, you avoid calories and stick with water, black coffee, or unsweetened tea. During the eating window, the focus is on whole foods, lean protein, whole grains, and healthy fats to support blood sugar control, heart health, and overall health.

Mistakes to Avoid

In addition to some key foods to avoid while intermittent fasting, this video shows fasting mistakes most people make:

🎥 Video Credit: Dr. Eric Berg DC

Popular Intermittent Fasting Approaches

Intermittent fasting can be done in different ways depending on your schedule and health goals. These are the more popular approaches people follow:

16:8 Method – Fast for 16 hours, eat within an eight-hour window.
14:10 or 12:12 – A good option for beginners who want more flexibility.
Alternate-Day Fasting – Eat normally one day, restrict calories the next fast day.
Extended Fasting Periods – 24 hours or more; best short term and under supervision.

Choosing the right schedule across the hours of the day helps you stick with your foods to avoid while intermittent fasting plan for the long term.

💪 Power Tip: Start with a beginner-friendly eating plan like 12:12, then adjust to longer fasting windows once your body adapts.

Foods to Avoid While Intermittent Fasting

Here’s an updated list of the foods to avoid while intermittent fasting. These either break your fast or make fasting harder by spiking blood sugar, increasing hunger, or slowing fat burning.

	Food	Why to Avoid
#1.	Sugary sodas and sweet teas	Full of added sugar; cause blood sugar spikes, increase calorie intake, and immediately break a fast.
#2.	Fruit juice (even “no added sugar”)	High in natural sugars; digested quickly and disrupt blood sugar control during an intermittent fasting diet.
#3.	Fancy coffee drinks (lattes, mochas, frappes)	Contain milk, cream, and syrups that add calories and fat, ending the fasting window.
#4.	Coffee creamers and flavored syrups	Even small amounts of milk, sugar, or flavoring increase calories and insulin response.
#5.	Energy drinks with sugar	Large sugar load raises blood sugar levels and causes energy crashes.
#6.	“Sugar-free” energy drinks (for some; can spur cravings)	Artificial sweeteners may cause hunger, cravings, and digestive problems in some people.
#7.	Alcohol of any kind	Adds empty calories, slows fat burning, and strains the digestive system and liver.
#8.	Smoothies and smoothie bowls	Even healthy smoothies contain calories and sugars that end a fast.
#9.	Protein bars with syrups or sugar alcohol stacks	Often processed and calorie-dense; spike insulin and disrupt fasting benefits.
#10.	Candy (all types)	Pure sugar; leads to blood sugar spikes, weight gain, and cravings.
#11.	Pastries and donuts	High in refined carbs, trans fats, and sugar; cause digestive issues and disrupt energy levels.
#12.	Sweetened breakfast cereals	Loaded with sugar and refined grains; increase body fat and blood sugar spikes.
#13.	White bread and refined flour products	Lack fiber and essential nutrients; quickly raise blood sugar and insulin levels.
#14.	White rice and instant noodles	Simple carbs digested rapidly, causing spikes in blood sugar and hunger soon after.
#15.	Chips, crackers, and snack mixes	High in sodium, oils, and refined carbs; encourage overeating and poor food choices.
#16.	Deep-fried foods and fast-food sides	High in calories and unhealthy fats; contribute to heart disease and digestive problems.
#17.	High-sugar yogurts and parfaits	Often more dessert than food; add sugar and artificial ingredients that break a fast.
#18.	Granola sweetened with honey/agave/syrup	Marketed as healthy but calorie-dense; raise blood sugar and stall weight loss goals.
#19.	Heavy cream sauces and cheesy dips	High in saturated fats and calories; interfere with the metabolic switch to fat burning.
#20	Diet sodas/artificial sweeteners (for sensitive individuals)	Can trigger cravings, insulin response, and side effects like bloating.
#21.	Gum and mints with sugar (and constant sugar-free chewing)	Sugar ends a fast; constant chewing can stimulate hunger and digestive system activity.

Foods to Eat During Fasting and Eating Windows

Choosing the right foods is just as important as avoiding the wrong ones. Here’s how to fuel your foods to avoid while intermittent fasting across both fasting and eating windows:

During the Fasting Window – Keep your food intake calorie-free and clean. Stick with water (still or sparkling), black coffee, or unsweetened tea. On a long fast day, electrolytes without sugar are a good option to maintain hydration and energy levels. Staying consistent across the hours of the day helps you reach your health goals and ensures intermittent fasting works effectively.
During the Eating Window – Focus on nutrient-dense choices instead of the wrong foods. The best foods include lean meats like chicken or fish, whole grains such as oats or quinoa, leafy greens, and colorful vegetables. Add unsaturated fats from avocado, nuts, or olive oil to support heart health, reduce high blood pressure, and manage high cholesterol. Building each small meal around one protein, one vegetable, and one healthy fat is a good option for balancing body weight and long-term wellness.

By planning your eating windows carefully, you’ll avoid common mistakes, protect your long-term health goals, and get the full benefits of intermittent fasting.

💪 Power Tip: A healthy meal pattern with the right foods during your eating period is just as important as knowing the foods to avoid while intermittent fasting.

Intermittent Fasting Cookbooks

Cookbooks can help simplify your foods to avoid while intermittent fasting strategy by giving you a structured eating plan for non-fasting days and re-feed meals. They highlight nutrient-dense foods and remind you of food restrictions so you can avoid the worst foods and still enjoy a healthy diet. Here is one of my favorite intermittent fasting cookbooks.

PIN IT

Intermittent Fasting for Beginners Meal Plan & Cookbook

This cookbook offers a 28-day intermittent fasting meal plan with easy, balanced recipes and ready-to-use shopping lists. It focuses on nutrient-dense ingredients that help boost metabolism, stabilize blood sugar, and support healthy digestion.

If you want more ideas check out my post on the 5 Best Intermittent Fasting Diet Cookbooks.

Long-Term Guidelines for Intermittent Fasting

Intermittent fasting works best when it’s consistent, balanced, and focused on nutrient-dense and nutritious foods. Over time, keeping your eating plan simple and knowing the foods to avoid while intermittent fasting ensures better results for weight, energy, and overall health.

During Fasting Periods – Stick with calorie-free drinks like water, black coffee, or herbal teas. Avoid any food intake so you remain in a fasted state and get the full benefits of intermittent fasting.
During Eating Windows – Build meals around lean protein, leafy greens, whole grains, and healthy fats. Limit sugary foods and red meat-heavy meals, as these are common mistakes that disrupt blood sugar control, cholesterol levels, and long-term heart health.
For Long-Term Success – A balanced diet and consistent intermittent fasting regimen improve insulin sensitivity, reduce chronic disease risks, and support a healthy weight. By focusing on the right foods and remembering the foods to avoid while intermittent fasting, you set yourself up for the best results.

Following a healthy meal pattern across your periods of eating helps protect against serious health conditions. Unlike a typical diet focused only on short-term calorie restriction, intermittent fasting encourages sustainable food choices that manage body weight and promote overall wellness. Staying consistent makes intermittent fasting work both day-to-day and for long-term good health.

Common Mistakes Beginners Make

Even with the best foods in your eating plan, it’s easy to fall into habits that hurt progress. One mistake is overeating during the eating window, often squeezing too many calories into a small meal. Another is breaking your fast with sugary foods, which spikes blood sugar and can worsen high blood pressure or high cholesterol.

Skipping nutrient-dense foods like lean meats, whole grains, or leafy greens is another common pitfall. These are the best foods for long-term energy and overall good health.

💪 Power Tip: Always break your fast with lean protein, veggies, and unsaturated fats for balanced energy.

FAQs

1. What is time-restricted eating and how does it work?

Time-restricted eating is one of the more popular approaches to intermittent fasting. It limits food intake to a set time period each day, often eight hours. This supports good health by controlling blood sugar and reducing caloric intake. Understanding the foods to avoid while intermittent fasting ensures this short term method delivers the best results.

2. Which types of foods should I include in my eating plan?

Focus on healthy foods such as lean protein, whole grains, and leafy greens. These nutrient-dense foods provide essential vitamins and minerals while supporting cholesterol levels and insulin sensitivity. During eating windows, avoiding sugary foods and the wrong foods helps intermittent fasting work long term, supports a normal eating pattern, and protects against chronic disease.

3. Can alternate day fasting affect how much weight I lose?

Yes, alternate day fasting can improve insulin sensitivity and accelerate fat loss. But your amount of calories on non-fasting days matters. If you eat the wrong foods, you may not see results. Choosing healthy foods, watching food intake quality, and remembering the foods to avoid while intermittent fasting leads to better weight management.

4. What happens if I overeat during my eating period?

Overeating the wrong foods during an eating window can cause bloating, weight gain, and digestive issues the next day. Extended fasting periods won’t undo poor food choices. Human nature often pushes toward extra calories after fasting diets, but balancing meals with nutrient-dense foods helps maintain good health and supports long term intermittent fasting results.

5. Do fasting diets have side effects on heart health or cholesterol levels?

Most fasting diets improve cholesterol levels, support heart health, and reduce chronic disease risks. However, side effects can occur if you eat too many processed or sugary foods. Maintaining a healthy eating plan, prioritizing nutrient-dense foods, and learning the foods to avoid while intermittent fasting can reduce these risks and protect overall good health.

6. Are fasting diets effective for both short term and long term goals?

Yes. In the short term, fasting diets can trigger a metabolic switch that burns body fat. Over the long term, consistency is key. Following a normal eating pattern with whole foods and avoiding the worst foods ensures sustainable weight loss. The benefits of intermittent fasting depend on discipline and food choices across days of the week.

Benefits of Intermittent Fasting Backed by Research

The benefits of foods to avoid while intermittent fasting go far beyond short term weight loss. Studies show that consistency across fast days and eating windows supports long-term health goals:

Improves insulin sensitivity, lowers fasting insulin, and supports blood sugar control (Sutton et al., 2018, Lu et al., 2025).
Enhances lipid profiles by lowering total cholesterol, LDL, and triglycerides while reducing inflammation (Song et al., 2022).
Provides cardiometabolic improvements even without weight loss, such as better blood pressure and β-cell responsiveness (Sutton et al., 2018).
Delivers measurable improvements in glucose, insulin resistance, immune system response, BMI, and waist circumference in people with metabolic syndrome (Yuan et al., 2022).
Supports favorable metabolic outcomes across multiple fasting diets when compared to standard calorie restriction (Sun et al., 2024).

💪 Power Tip: The best results come from repeating healthy food choices across the hours of the day – not just one perfect fast day.

Conclusion: Foods to Avoid While Intermittent Fasting

Success with intermittent fasting depends on more than just skipping meals-it’s about knowing the right foods to eat and the foods to avoid while intermittent fasting. Avoiding sugary drinks, fried foods, and processed snacks protects your fasting window, stabilizes blood sugar, and supports weight loss.

By building a normal eating pattern with nutrient-dense foods like whole grains, lean protein, leafy greens, and healthy fats, you’ll improve cholesterol levels, reduce chronic disease risks, and enjoy better energy. Over time, staying consistent with your intermittent fasting regimen sets you up for good health and long-term success.