Nutrition Weight Management

Can Intermittent Fasting Cause Weight Gain – Reasons, Tips & Risks 2024

Intermittent fasting, or IF for short, is a widely used strategy to achieve weight loss and additional health benefits such as muscle growth, improved digestion and hormonal balance during intermittent fasting. Intermittent fasting involves alternating between periods of food consumption (or eating) and periods of food abstinence. There’s a variety of outcomes you can expect from intermittent fasting, along with different methods of implementing IF. Finding an approach that works for your body may take some trial and error.

While IF is a preferred approach for many people, the potential side effects of intermittent fasting should be noted, so it is important to monitor your progress with a healthcare provider. It’s beneficial to think of IF as just one component in your wellness toolkit, and it’s advisable to combine IF with healthy exercise, a balanced diet, and supplements such as the best probiotics for shedding pounds (consider reading this review of Ritual Synbiotics).

What Happens If You End Your Fast Incorrectly?

Limiting your food intake to certain times can offer many health benefits through intermittent fasting (IF), but what you eat, how fast and how much are also key. Starting with food choice, it's normal to feel very hungry after fasting and to crave everything. However, experts advise caution when choosing foods to break your fast.

Whole, unprocessed, nutrient-rich foods such as lean proteins, healthy fats, vegetables, fibre and probiotics are best. Avoid foods high in sugar and carbohydrates. Eating these can cause blood sugar spikes, which can lead to hunger pangs, hormonal imbalances, potential weight gain and digestive problems such as indigestion, gas, bloating and discomfort.

Similarly, overeating or eating too quickly is problematic. Both can cause digestive problems and interfere with your IF goals. To feel good, balance hormones and lose weight, eat slowly, chew thoroughly and control portion sizes.

Is Intermittent Fasting Effective For Everyone?

Intermittent fasting can be effective for weight loss and health improvement, but it’s not for everyone. Its effectiveness depends on individual health conditions, lifestyle and metabolism. People with certain medical conditions or dietary requirements should consult a healthcare professional before starting. It’s important to be cautious and consider your personal health and nutritional needs.

What Is Intermittent Fasting?

Intermittent fasting, as the name suggests, involves fasting in an intermittent or non-continuous manner. The practice of intermittent fasting involves alternating periods of fasting with periods of eating (known as ‘feeding windows’). There are several methods of doing IF, not just one. In fact, there are different strategies for alternating between eating and fasting. The most common methods of intermittent fasting include

16/8: This technique is about fasting hours versus eating hours. In this method, an individual fasts for a 16 hour window and limits their eating to an 8 hour window. For example, you might only eat between 10am and 6pm each day and fast overnight from 6pm to 10am the next day.

5/2: In this method, 5 represents the number of consecutive days of normal eating, followed by 2 consecutive days of reduced calorie consumption, typically around 500 calories per day. For example, eating normally from Monday to Friday, then reducing calorie intake to about 500 calories on Saturday and Sunday.

OMAD (One Meal A Day): The OMAD regimen is similar to Eat-Stop-Eat, but involves fasting for about 23 hours a day. This means that you consume all of your daily calories within one hour of eating each day.

Warrior diet: This diet requires fasting for 20 hours a day, leaving a 4-hour window for eating in the evening. During the fasting periods, low-calorie foods such as raw fruit or vegetables and some lean protein are allowed.

Alternate day fasting: This approach consists of alternating days of fasting and normal eating. On the fasting days, you can either abstain from food altogether (if you can tolerate it) or limit your calorie intake to about 500 per day.

Eat-Stop-Eat: This strategy involves choosing one or two 24-hour fasting periods each week. For example, you might eat breakfast and then fast until breakfast the next morning. During these 24-hour fasts, calorie-free drinks such as seltzer, water, tea or coffee are recommended.

How Can I Stay Motivated During Intermittent Fasting?

How Can I Stay During Intermittent Fasting Motivated

To stay motivated during intermittent fasting, set clear, achievable goals and remind yourself of the benefits, such as improved health and weight management. Start with a manageable fasting schedule and gradually increase the duration as your body adjusts. Keep yourself hydrated and busy during fasting hours to distract yourself from hunger.

Tracking your progress, celebrating small victories and maintaining a supportive environment, either through online communities or with friends, can also boost motivation. Remember that consistency is key, so focus on making small, sustainable changes rather than looking for quick results.

Reasons Why You May Gain Weight During Intermittent Fasting

Eating Too Much

Hunger is a natural consequence of fasting. However, it’s important to avoid the urge to overeat after a fast. The idea behind Intermittent Fasting (IF) is to restrict calories during limited periods of eating. However, consuming too many calories during these periods could negate the benefits. It’s important to maintain regular meal sizes and portions. Eating at a leisurely pace and with awareness helps to avoid overconsumption.

Consuming Too Much Sugar

Eating too much sugar and/or carbohydrate (especially alone, without protein, fat and fibre) can cause blood sugar spikes. Even sugar substitutes and artificial sweeteners can have this effect on blood sugar. Not all people notice this reaction in their bodies, but sugar does cause more insulin to be released, which can lead to insulin resistance, diabetes and weight gain. Last but not least, this mechanism predisposes us to increased hunger later on, paving the way for increased calorie consumption.

Eating Fast

It’s not just what we eat, but how we eat. Another way to avoid digestive problems and weight gain is to be mindful of the pace at which we eat. After fasting, you may feel the urge to eat quickly. However, the body needs time to adjust, and overloading it with too much food too quickly can cause upset. An alternative is to sit down for breakfast and eat at a leisurely pace. Eating slowly and chewing thoroughly will help to gently reintroduce food into the body and help to recognise the onset of satiety, thus avoiding overeating later on.

Additional Lifestyle Elements

Remember that exercise, stress management and good sleep are essential for weight loss. If you are using an Intermittent Fasting (IF) approach, think about several aspects: Are you getting enough sleep? Are you managing your stress? Do you exercise regularly throughout the week? Without a balanced approach to these issues, your weight loss journey could stall. What’s more, the specific type of IF you’re doing may not be right for you, and you may need to explore different IF techniques to find the one that works best for you.

Eating Under Stress

Our nervous system operates in two distinct states: fight-or-flight and rest-and-digest, but not simultaneously. Therefore, when we are stressed and in fight-or-flight mode, it becomes difficult to digest food effectively. This can lead to digestive problems, poor nutrient absorption and possible weight gain.

Increased stress increases cortisol levels, which contribute to persistent belly fat and elevated blood sugar levels. In addition, stress often leads to further overeating. Ensure a relaxed, distraction-free environment at the end of your fast and sit comfortably for optimal mental clarity.

How Can I Maintain Muscle Mass While Intermittent Fasting?

To maintain muscle mass during intermittent fasting, ensure adequate protein intake during meal windows with foods such as lean meats, fish, eggs and plant-based options. Engage in regular strength training to stimulate muscle growth. It’s important to meet your daily calorie needs within your eating window to prevent muscle loss. Stay well hydrated, as dehydration can be detrimental to muscle health. Also prioritise sleep and recovery as these are essential for muscle repair and growth.

Can Intermittent Fasting Cause Weight Gain?

The short answer is yes: intermittent fasting can lead to weight gain, although that’s not its purpose. Intermittent fasting (IF), known for its many health benefits, is typically a fast weight loss method. However, there are individual differences and factors such as your unique metabolic rate, hormonal balance and genetic make-up can influence whether IF causes you to lose or gain weight. It’s also worth noting that some people may experience weight gain from IF in muscle mass rather than fat, which could be a beneficial outcome.

Weight gain could also be an adverse effect of IF if it is not followed properly. According to the principles of the diet, it’s important to stick to specific eating and fasting times, but there’s more to it than that. Fasting can cause intense hunger, leading people to eat larger portions than necessary. In addition, fasting can trigger binge eating episodes, where people not only overeat, but also overlook the quality of the food consumed during their meal breaks. The choice and amount of food eaten has a significant impact on potential weight gain during IF.

What Are The Potential Risks?

While intermittent fasting may be beneficial for some, there are potential risks. These include nutrient deficiencies due to the restricted eating periods, which can lead to inadequate vitamin and mineral intake. It can also disrupt blood sugar levels, leading to hypoglycaemia, especially in people with diabetes. Fasting may cause eating disorders or worsen existing ones, as it can lead to an unhealthy obsession with food and eating patterns.

It can also cause fatigue and difficulty concentrating due to energy fluctuations. In addition, intermittent fasting may not be suitable for pregnant women, children and people with certain medical conditions.

Frequently Asked Questions

Does the type of Intermittent Fasting method affect weight gain?

Yes, different methods (like 16/8, 5:2, or alternate-day fasting) have varying effects on eating patterns, metabolism, and might impact weight differently.

Can Intermittent Fasting slow down metabolism?

Long-term fasting might slow metabolism, but short-term fasting, like in IF, typically does not have this effect. However, individual responses can vary.

How can I prevent weight gain while practicing Intermittent Fasting?

Focus on balanced, nutrient-dense meals during eating periods, avoid overeating, and maintain a consistent fasting schedule.

Does breaking an Intermittent Fasting routine lead to weight gain?

Returning to normal eating habits suddenly can lead to weight gain, especially if not coupled with mindful eating and regular physical activity.

Should I exercise while on an Intermittent Fasting regimen to prevent weight gain?

Yes, regular physical activity can help manage weight and boost metabolism, complementing the effects of IF.


Intermittent fasting, or the technique of alternating fasting periods with eating intervals, is a method used by many people for weight loss and hormone regulation, as well as other health benefits. There are several known approaches to Intermittent Fasting (with others available), ranging from alternate day fasting, to adhering to specific hourly fasting schedules each day, to more intensive forms.

In general, Intermittent Fasting is associated with weight loss rather than weight gain. However, improper use of intermittent fasting, including suboptimal dietary choices, excessive food consumption and unhealthy lifestyle habits, can potentially lead to weight gain.


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Jayson Peterson is an experienced pharmacist, naturopathic physician, medical examiner, and minister. After earning his Doctor of Pharmacy degree from the Medical University of South Carolina, Jayson Peterson completed clinical rotations at several prestigious healthcare institutions and has been affiliated with several pharmacy chains throughout his career. His main passion and zeal is focused on providing world-class patient care by giving precise details and thorough instructions to those who need it most.

By Jayson Peterson

Jayson Peterson is an experienced pharmacist, naturopathic physician, medical examiner, and minister. After earning his Doctor of Pharmacy degree from the Medical University of South Carolina, Jayson Peterson completed clinical rotations at several prestigious healthcare institutions and has been affiliated with several pharmacy chains throughout his career. His main passion and zeal is focused on providing world-class patient care by giving precise details and thorough instructions to those who need it most.