Why am I gaining weight when intermittent fasting?

Intermittent fasting has become a popular diet trend in recent years. Intermittent fasting means limiting eating to certain time periods, and fasting, or consuming no food, at specific times.

There are many types of intermittent fasting, and some may be more likely to help you lose weight than others. Does fasting make you gain weight? Despite intermittent fasting being a touted as a way to lose weight, in some cases, you may find yourself gaining weight while intermittent fasting.

Let's take a look at the reasons why, and what you can do to avoid gaining weight while fasting.

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Intermittent Fasting Weight Gain

First, it's important to understand the difference between gaining weight while fasting and weight gain caused by intermittent fasting. While they seem similar at first glance, they are very different things.

As humans, we have an incredible and frustrating ability to gain weight. This has helped humans survive for 300,000 years. It provides a reserve of fat and energy when food isn't readily available.

Given our capacity to pack on pounds, gaining weight with intermittent fasting shouldn't come as a surprise. This doesn't mean that the weight gain is caused by fasting. Weight gain can be caused by fasting, but it can also occur for many other reasons, including increased calorie intake, reduced physical activity, or eating more processed foods.

Why Am I Gaining Weight on Intermittent Fasting?

Can fasting make you gain weight? Yes, it can. It's a common issue in the first week of fasting. However, weight gain intermittent fasting can occur even after the first week. Why do you gain weight while fasting?

Calorie Concerns

The most common reason for gaining weight while fasting is due to calories being too high or too low.

When you have eating windows, you may find yourself eating more during those windows. If this adds up to a higher daily calorie count than you are used to, you will gain weight. This can occur because your body is craving more calorie-heavy foods, or you may eat a larger quantity of food. Keep in mind, that eating windows themselves will not help you lose weight. You'll need to pair it with healthy choices.

However, too many calories isn't the only issue that can cause you to gain weight while fasting. If you are eating too few calories, this can also cause you to gain weight. When you don't consume enough calories, your body will slow its metabolism to compensate. So, if you reduce your calorie intake too much, your body will hold onto the calories rather than burn them, which leads to weight gain even though you are eating less.

Reduced Physical Activity

The key to weight loss is to burn more calories than you consume. You can think of it as a simple math equation, with calories consumed on one side, and calories burned on the other. If the calories burned are greater, you'll lose weight.

Exercise is a great way to burn calories. How many calories you burn will depend on your weight, the activity itself, and the duration of the activity.

For example, 30 minutes of weight lifting burns about 100 calories, and yoga burns approximately 140. Low-impact aerobics can burn around 200 calories in half an hour.

In addition to the calories burned during the workout, your body continues to burn more calories for several hours after your workout.

Fasting, particularly in the early weeks, can cause fatigue as your body adjusts. If you are feeling tired, you are less motivated to exercise. If you slow down on your exercise routine, weight gain may result.

"Cheating" During Fasting Window

"Cheating" or consuming calories during your fasting window can also cause you to gain weight while fasting. Some people find their bodies more forgiving than others when it comes to what can be consumed during the fasting window.

For some, even a spoon of cream and sugar in coffee is enough to pull the body out of fasting mode, reducing weight loss.

Technically, any calories consumed break your fast. However, experts say that unsweetened tea, coffee, small amounts of fat like MCT oil, and bone broth don't have a big impact on the benefits of fasting, and may make the fast easier to stick to.

However, you will want to avoid foods, any type of sugar or carbs, and large amounts of fat.

Eating the Wrong Foods

We've already discussed the issue of eating too many calories. However, it's also critical to eat quality foods. It may be tempting to reward yourself with highly processed or fatty foods, or sugary sweets. These types of foods will negate many of the benefits that intermittent fasting brings.

Fasting too Long too Soon

If you have recently begun fasting, it's important to start slowly. It's not a good idea to jump into fasting for 24 hours or more. Eating for 8 hours and fasting for 16 is typically a good starting point. This allows you to eat for 8 hours, and then fast for the next 16 hours. 16 hours may seem like a long time, but you'll spend at least half of this time sleeping.

Intermittent Fasting Weight Gain First Week

You have just begun your intermittent fasting journey. It's been about a week, and you excitedly step on the scale expecting some good news. To your disappointment, you find you've actually gained weight. What happened?

Water Retention

When you begin fasting, your body will initially reduce its water use to conserve energy. The body does this because it thinks it is in a period of scarcity, where energy must be conserved for survival.

This means your body retains water, which can show up as extra pounds on the scale. The good news is that this weight will go away when the extra water is released.

Increased Hunger

When you first begin fasting, you may feel more hungry than before. This can cause you to consume more calories during your eating window. If your calorie consumption goes up, this can lead to weight gain.

Hormonal Changes

Because your body goes into a state of scarcity when you are fasting, your body may increase hormones that tell your cells to store more fat. This is temporary, and usually resolves within a few weeks of beginning the diet.

Muscle Gain

Intermittent fasting gaining weight isn't always a bad sign. If you are engaging in strength training while intermittent fasting, you may be building more muscle mass. Muscle is significantly heavier than fat, so building muscle can result in weight gain, even though your body is slimming down.

Types of Intermittent Fasting

There are several different types of intermittent fasting.

Time Restricted Eating

The most common is known as Time Restricted Eating, or TRE. This method involves having a certain amount of time each day where you fast, or avoid eating, and a period of time when you consume food.

While 16 hours fasting and an 8-hour eating window are the most common, you can adjust the timing to suit your needs and preferences. Options include fasting for 18 hours and eating for 6, or fasting for 14 hours and eating for 10 hours.

Alternate Day Fasting

Alternate Day Fasting, or ADF, is another option. Technically this type of fast isn't a true fast, as you will consume calories on your fasting days. You can fast one day and eat normally the next, consuming 500 calories on fasting days. You can also eat normally 5 days of the week, and fast for the other two days with reduced calorie consumption on fasting days.

Other Fasts

The Warrior fast is on the challenging side, as you won't consume any calories for nearly 24 hours. This involves fasting for 20 hours, and then consuming a large meal within a 3-4 hour window.

One Meal a Day (OMAD) is another option. As the name suggests, you'll eat a large meal once a day around the same time, and fast for the remainder of the day.

A simpler option for intermittent fasting is to simply skip meals when you aren't hungry. Lastly, some people prefer a 24 hour fast, which means you'll go 24 hours without consuming calories.

Which Type of Fasting is Best for Weight Loss?

According to a meta-analysis, alternate-day fasting, or ADF, is the most effective for weight loss. In fact, it's even more effective than calorie reduction. While time-restricted eating does provide results as well, it's not as effective as calorie restriction and ADF.

Bottom Line on Weight Gain While Fasting

If you are wondering "Why am I gaining weight while intermittent fasting?" now you know the potential causes and what you can do to get back on track. It is important to listen to your body and set goals that you can stick with. If your current intermittent fasting plan is causing weight gain, consider making some adjustments to your fasting schedule, food intake, or activity level