It’s tempting to speed through the weight loss process with a crash diet for a week or two, but you should always be aware of all the risks and complications. Skipping meals or eating way less calories than you need can do more than damage your health, it can actually lead to the opposite of the intended effect.

Find out more about the reasons crash diets can make you gain weight, and decide if you’re better off making smaller changes that lead to sustainable weight loss, instead of trying fad diets that don’t work in the long run and can actually take you farther from your goal.

1. Your Metabolism Slows Down

Reducing your food intake drastically is a signal for your body to reduce the metabolic rate in order to store everything it can. When you’re on a crash diet, your body basically goes into starvation mode, and you’re a lot more likely to gain weight faster once it’s over. Slowing down your metabolism can’t be reversed easily, so you can expect to gain it all back or even add more.

2. You’re More Likely to Overeat Afterwards

One of the most important reasons crash diets can make you gain weight is the fact that you’ll also be tempted to eat more once the diet is over. The combination of more fat storage with binge eating is a recipe for disaster when it comes to your weight.

Crash Diets Make You Fat

3. You’re Losing Muscle Mass on a Crash Diet

Major calorie restrictions can lead to losing water weight temporarily. Once that’s gone, your body turns to your muscles to provide the energy it’s not getting from your means. Losing muscle mass is bad, since once the diet finishes, it won’t come back. When you gain weight after a crash diet, it will most likely be fat, so you’ll be in worse shape than when you started.

4. You’ll Burn Less Calories with Workouts

Because of the decreasing muscle mass, you’ll have a harder time keeping up with your workouts. Loss of energy is also one of the reasons crash diets can make you gain weight, since you won’t be able to give 100% at the gym, and you’ll be a lot more likely to skip a workout.

More: How NOT to Start a Diet

5. You’re Not Getting Fatty Acids

Most crash diets are very low on fat, but they don’t really discriminate between good and bad fats. Cutting back fatty acids from your diet can mess with your metabolism even more, slowing it down to a crawl while you’re severely restricting calories, and making it less efficient when it comes to burning fats.

6. Your Mood Can Get Altered

Some people end up battling depression after a long time of yo-yo dieting and severe calorie restrictions. Even if that won’t happen to you, mood swings are also one of the reasons crash diets can make you gain weight. When you’re not feeling well, you’re more likely to give in to your worst food cravings, that will be quickly turned into fat deposits.

Mood Altered While Dieting

7. Your Immunity Is Lowered

Not getting the right vitamins and minerals because you’re on a crash diet can also wreak havoc on your immune system. The risk of catching a cold or other infections or diseases will be higher. Even if you won’t be bed ridden, you’ll be a lot less motivated to make the right choices when it comes to food and to work out.

8. Your Digestion Can Be Slowed Down

Most crash diets can also have a big impact on your digestion, usually slowing it down. Even if you can deal with the discomfort of constipation, this is also one of the reasons crash diets can make you gain weight.

See also: Comfort Foods You’ll Regret Eating

9. You’re at Risk for Developing Bulimia

If crash diets become a habit, and you turn into a victim of yo-yo dieting, you’re at a much higher risk for developing eating disorders. Severe calorie restrictions can lead to anorexia, but you can also develop bulimia, both of which are very dangerous for your health in the long run, or you can also get used to binge eating without the purging.

10. You Can Develop Heart Disease

Repeated crash diets can also lead to an increased risk of heart disease. Developing a cardiac condition is also one of the reasons crash diets can make you gain weight, since you’ll have to face restrictions when it comes to working out. And when your options for calorie burning are restricted, you can easily gain more weight.