Does Phentermine Break A Fast?

Have you ever wondered if taking medication during your fasting period will break your fast? Specifically, what about Phentermine, a popular weight loss medication? Well, you’re not alone. Many people who are fasting and trying to lose weight have questioned whether or not taking Phentermine will affect their progress. In this article, we’ll explore the science behind fasting and Phentermine and help you determine if taking this medication will break your fast.

Fasting has become a popular trend in recent years, with many people using it as a way to lose weight, improve their overall health, and even increase their lifespan. However, the rules around fasting can be confusing, especially when it comes to taking medication. Phentermine is a stimulant medication that suppresses appetite and is often used for weight loss. But does taking Phentermine break a fast? Let’s find out.

Yes, phentermine breaks a fast. Phentermine is an appetite suppressant and a stimulant that increases metabolism. It can raise insulin levels, which breaks the fast. Additionally, it can cause stomach upset and dehydration, which can interfere with the fasting process. It is best to avoid taking phentermine while fasting.

Does Phentermine Break a Fast?

Does Phentermine Break a Fast?

Intermittent fasting is becoming increasingly popular as a weight loss strategy. It involves cycling between periods of eating and fasting. During the fasting period, you are supposed to avoid consuming any calories or nutrients, including vitamins and supplements. However, some people may be on medications that they need to take during the fasting period. One such medication is Phentermine. But does taking Phentermine break a fast? Let’s find out.

What is Phentermine?

Phentermine is a prescription medication used to suppress appetite and aid in weight loss. It belongs to a class of drugs called sympathomimetic amines. It works by stimulating the release of chemicals in the brain that control appetite. Phentermine is usually prescribed for short-term use, along with a proper diet and exercise program.

How does Intermittent Fasting Work?

Intermittent fasting involves alternating periods of eating and fasting. During the eating period, you consume all your daily calories, and during the fasting period, you consume no calories. There are various methods of intermittent fasting, such as the 16/8 method, where you fast for 16 hours and eat within an 8-hour window.

What Breaks a Fast?

The definition of what breaks a fast is subjective and varies depending on the individual and the type of fast they are following. However, the general rule is that anything that can stimulate digestion or increase insulin levels may break a fast. This includes consuming calories, nutrients, and even some medications.

Does Phentermine Break a Fast?

Phentermine is a medication that can increase heart rate and blood pressure, which can stimulate digestion and increase insulin levels. Therefore, taking Phentermine during the fasting period may break a fast. However, if you need to take Phentermine for medical reasons, it’s best to consult your doctor before starting an intermittent fasting regimen.

The Benefits of Intermittent Fasting

Intermittent fasting has been shown to have numerous health benefits. It can aid in weight loss, improve insulin sensitivity, lower inflammation, and even promote longevity. By restricting the eating window, you are reducing the number of calories consumed, which can lead to weight loss. It also allows your body to repair and regenerate during the fasting period.

The Benefits of Phentermine

Phentermine is a medication that can aid in weight loss by suppressing appetite. It can also improve metabolic rate and energy levels. It’s usually prescribed for individuals with a BMI of 30 or higher, or those with a BMI of 27 or higher with obesity-related conditions such as diabetes or high blood pressure.

Intermittent Fasting Vs. Phentermine

Intermittent fasting and Phentermine are both weight loss strategies that work in different ways. Intermittent fasting restricts the eating window, while Phentermine suppresses appetite. Both can aid in weight loss, but it’s best to consult your doctor before starting any weight loss regimen.

The Bottom Line

In conclusion, taking Phentermine during the fasting period may break a fast as it can stimulate digestion and increase insulin levels. However, if you need to take Phentermine for medical reasons, it’s best to consult your doctor before starting an intermittent fasting regimen. Intermittent fasting and Phentermine are both effective weight loss strategies, but it’s important to find the one that works best for you and your lifestyle.

Frequently Asked Questions

Here are some common questions regarding phentermine and fasting:

What is Phentermine?

Phentermine is a prescription medication used to aid in weight loss. It works by suppressing appetite and increasing energy levels. It is typically prescribed for short-term use in conjunction with diet and exercise.

While it can be effective in helping to lose weight, it can also have potential side effects and should only be taken under the guidance of a healthcare provider.

What is Fasting?

Fasting is the practice of abstaining from food and/or drink for a certain period of time. It is often done for religious or health reasons and has been shown to have potential benefits such as weight loss, improved blood sugar control, and decreased inflammation.

There are various types of fasting, including intermittent fasting, which involves alternating periods of eating and fasting, and extended fasting, which can last for several days.

Can You Take Phentermine While Fasting?

It is generally not recommended to take phentermine while fasting. While it may be tempting to use phentermine to help control hunger during a fast, it can potentially have negative effects on the body.

Phentermine can increase heart rate and blood pressure, which can be dangerous during a fast when the body is already under stress. Additionally, taking phentermine on an empty stomach can increase the risk of side effects such as nausea and dizziness.

Does Phentermine Break a Fast?

Yes, taking phentermine can break a fast. Even though phentermine is a stimulant and does not contain calories, it can still have an impact on the body that can disrupt the benefits of fasting.

Phentermine can potentially increase insulin levels and decrease ketone production, which are two of the main benefits of fasting. Additionally, taking phentermine with food can further disrupt the fasting state.

What Are Some Alternatives to Phentermine While Fasting?

If you are looking to fast for weight loss, there are other options besides phentermine that may be more appropriate. Some natural appetite suppressants include green tea, apple cider vinegar, and ginger.

Additionally, practicing mindful eating habits and incorporating regular exercise can help control hunger and promote weight loss without the use of medication.

Adding Phentermine to my Intermittent Fasting


In conclusion, the answer to the question of whether Phentermine breaks a fast is not straightforward. While it does not contain any calories, it may still trigger an insulin response in the body, which could break a fast. However, the effects of Phentermine on fasting may vary from person to person, depending on various factors such as metabolism, weight, and medical history.

If you are taking Phentermine and want to continue your fasting routine, it is essential to consult your healthcare provider. They can advise you on the best approach based on your individual needs and goals. Additionally, it is crucial to listen to your body and pay attention to any changes in your hunger levels, energy, and overall health.

In the end, the most important thing is to find a sustainable and healthy approach to weight loss that works for you. Whether it involves fasting or not, make sure to prioritize your well-being and seek professional guidance if needed. Remember, the journey to a healthier you is a marathon, not a sprint, and every small step counts towards your ultimate goal.

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