The Truth Behind Diet Pills — They Don't Work And Can Be Dangerous

We have to work for what we want. As much as we would like this not to be the case, it is especially true when it comes to losing weight.

Most people want to lose a few extra pounds. Whether you’re looking to lose some excess weight for your next big event or would like to improve your overall health and wellness, the concept of taking a pill to help your weight-loss journey can sound enticing. In reality, it isn’t the “one-stop-shop” solution people are looking for.

According to the Centers for Disease Control and Prevention (CDC), over 41% of Americans (roughly 93 million adults) met the criteria to be diagnosed with obesity between 2017 and 2020¹. Alongside the steady increase in obesity, the American healthcare system is experiencing increases in other chronic medical conditions like heart disease, diabetes, and high blood pressure — all conditions associated with a higher risk of carrying excess weight.

As weight gain and obesity continue to rise across the United States and worldwide, it should be no surprise that weight-loss therapies are also becoming more popular. From fad diets to weight-loss supplements and prescriptions, a neverending sea of “quick-fix” options is available for anyone looking to lose weight. But are they always safe, and is there really a miracle pill for weight loss?

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What are diet pills?

As it turns out, even weight-loss therapies prescribed by doctors are not always as effective and safe as they appear.

Diet pills (also known as weight-loss pills) have been a popular option for people looking to lose weight for over 100 years. Available in many different forms over the years, the goal of diet pills is to achieve some of the following effects:

  • Reducing your food cravings

  • Speed up your metabolism to burn more fat

  • Make you feel full without having to eat as much food

  • Slow down your body’s fat creation and storage process

  • Prevent your body from absorbing fat from meals

However, no miracle pill can achieve all of these outcomes. Instead, prescription diet pills are sorted into broader categories based on their mechanism:

  • Stimulants: Designed to impact the central nervous system to increase energy production while curbing overall appetite. Examples of stimulant diet pills include phentermine and benzphetamine hydrochloride.² ³

  • Fat inhibitors: Designed to work on the gastrointestinal tract, fat-inhibitor diet pills can help people lose weight by reducing the amount of fat they absorb from their diet, e.g., Orlistat.⁴

  • Appetite suppressants: Created to target specific neurotransmitters in the brain, appetite suppressants help to produce feelings of fullness and have been known to lessen appetite. Examples of appetite-suppressing diet pills include diethylpropion, naltrexone, and bupropion.⁵ ⁶

The diet-pill controversy

Despite initial approval by the US Food and Drug Administration (FDA), many diet pills are eventually taken off the market — often after they cause serious side effects and complications.

Examples of once-popular diet pills that have now been banned, withdrawn or recalled from the American market include:

  • Fen-Phen: First approved as a weight-loss medication in 1973, Fen-Phen (fenfluramine with phentermine) helped patients lose weight by interacting with the neurotransmitter serotonin to suppress appetite. It quickly became popular, and by 1996 over 18 million Americans were taking Fen-Phen. But, after researchers found a consistent connection between taking Fen-Phen and an increased risk of serious complications like pulmonary hypertension, damaged heart valves, and even death, the FDA removed it from the market in 1997.⁷

  • Ephedra: A herbal supplement that was once commonly used in Chinese medicine, ephedra was often added to weight-loss supplements in the 1990s and 2000s. Due to the lack of regulation and monitoring of these products, there was no requirement for manufacturers to state how much ephedra was in their products. As a result, ephedra-poisoning symptoms began to rise, including serious complications like cardiac dysrhythmias, heart attacks, seizures, strokes, and death.⁸ In response to these findings, ephedra was banned by the FDA in 2004.⁹

  • Hydroxycut: Once one of the most popular herbal supplements used for weight loss in the United States, Hydroxycut was marketed as a “fat burner” due to its ability to prevent fat breakdown in the gastrointestinal tract. Unfortunately, it was found that taking Hydroxycut increased a person’s risk of experiencing severe liver and kidney damage. As a result, the FDA banned the use of Hydroxycut in 2009.¹⁰

  • Meridia (Sibutramine): First approved by the FDA in 1997 as a prescription weight-loss drug, Meridia was a popular choice for those looking to reduce their body mass index (BMI).¹¹ Meridia was marketed as a long-term appetite suppressant. But, once research began to show a connection between taking Meridia and developing serious cardiovascular complications like stroke and heart attacks, the provider voluntarily withdrew the drug from the market in 2010.

From “miracle solution” to misuse and overdose

Aside from the potentially life-threatening complications caused by taking prescription diet pills as directed, another serious health trend emerged as these medications became increasingly popular.

Diet pill misuse (overuse, poisoning, and even potential overdosing) can cause severe complications if left untreated. Often found in people living with eating disorders like anorexia and bulimia, abusing prescription diet pills can look like this:

  • Taking more than the recommended dose to lose more weight

  • Combining multiple diet pills and supplements without consulting a doctor

  • Taking diet pills despite having a normal or low BMI 

  • Combining diet pills with laxatives or diuretics to lose extra weight

  • Taking diet pills without a prescription from your primary care provider

  • Combining diet pills with illegal stimulants like methamphetamine and cocaine

Like any other medication, intentional misuse of diet pills can lead to the development of serious side effects and complications. Examples of some of the most common symptoms of diet-pill abuse include:

  • Dizziness¹²

  • Nausea and vomiting

  • Insomnia

  • Chest pain and heart palpitations

  • Developing a red, itchy rash

  • Dark urine

  • Light-colored stool

  • Swelling in the legs

  • Yellowing of the skin or eyes

  • Hallucinations

Despite the risks, diet supplement use is on the rise

So, as we can see, diet supplements and medications are not always as safe as they appear — but that hasn’t stopped people from taking them.

According to the Medicines and Healthcare Products Regulatory Agency (MHRA), nearly one-third of all diet pills are sold online through illegal websites.¹³ Often selling banned or restricted medications, these websites make a huge profit from people desperate to lose weight. Interestingly, in a survey conducted by MHRA in partnership with Slimming World, it was found that 4/10 users of illegal diet pills knew about the serious health risks associated with the medications — but that didn’t stop them from taking them.¹³

As the dietary supplement market continues to rise in popularity, so does the industry’s annual revenue. Currently estimated to have a market value of 1.13 billion USD, researchers believe that the diet pill market could grow to be worth upwards of 2.27 billion USD by 2028.¹⁴

Should I consider taking diet pills?

If you are desperate to lose weight as fast as possible, are diet pills and weight-loss supplements the way to go? In most cases, it seems like the answer is no.

Currently, due to the way the FDA categorizes health products, weight-loss supplements (excluding prescription diet pills) are not required to report the ingredients and dosage of their products. While it is requested that all health supplement manufacturers report the safety and efficacy of their products, not all companies comply — meaning that it is almost impossible to know exactly what you’re taking.

To provide additional education and raise awareness of this problem, the FDA released a list of tainted weight-loss products to reduce exposure.¹⁵ But, despite this effort, without regulated requirements for manufacturers to list their ingredients, you cannot be sure of the safety and efficacy of any health supplement you purchase.

There is no such thing as quick and easy weight loss

Losing weight cannot be achieved overnight or with a miracle pill. Shedding those extra pounds can often feel like a near-impossible task requiring hard work, dedication, and long-term commitment — but it doesn’t always have to be this way.

When we feel vulnerable and uncomfortable with our physical appearance, turning to a promised quick fix can be tempting. But, as we have learned, all diet pills come with hefty warnings and potential side effects — some don’t even work!

To avoid the health risks and disappointment, here are some of our top tips to consider before deciding to take weight-loss pills or supplements:

  • If it sounds too good to be true, it is: Nothing good comes easy, and if a product promises seemingly miraculous results, it is likely a lie. If you read an advert for a diet pill that claims to help you lose weight without having to do anything other than taking the medication, it is a scam!

  • Fast weight loss can be harder to maintain: When people have been able to lose weight by taking diet pills and supplements, they often find it hard to keep the weight off. Because weight-loss pills do not help patients to address the cause of their weight gain, it is common for people to gain weight after they stop taking the medications. Choosing a slower, lifestyle-based approach to weight loss is the best way to see long-term results.

  • Speak with your doctor before taking any new health product: Even though many health products are labeled as “healthy and natural alternatives,” they are not always safe. Consulting with your primary care provider before starting a weight-loss supplement is one of the best ways to keep yourself safe from potentially harmful side effects and interactions.

However, just because taking a diet pill is not the miracle solution you may have hoped for doesn’t mean there aren’t other, more sustainable options for losing weight.

Making small but consistent changes to your day-to-day routine can produce substantial results. Whether you are looking to lose a few pounds or want to change your current lifestyle for the better, here are some examples of lifestyle habits and changes that you may find helpful in your journey to improved health:

  • Increase your daily water intake: Water is essential for our overall health. While water does not replace eating a hearty meal, drinking more water throughout the day can help to keep your body hydrated. Choosing to drink a glass of water over a soda or juice can help cut back on calories while providing multiple health benefits.

  • Eat a balanced, nutrient-dense diet: While we enjoy a delicious meal, the real reason why we need to eat is to get the essential nutrients and energy for life. With this in mind, choosing to consume a healthy diet (high in vegetables, fruits, and whole grains) can nourish your body without a large number of calories.

  • Prioritize your sleep: In the modern world, it has become easy to stay up late and sabotage your sleep schedule. As an essential part of overall health, getting enough sleep every night has been shown to help with sustained weight loss. On average, an adult is recommended to sleep for a minimum of seven hours every night.¹⁶

  • Partake in daily exercise: As a great way to move your body and burn some energy, finding fun daily exercises you enjoy can help your weight-loss journey. Daily movement is key to improved health and wellness, starting with low-impact exercises like walking, gardening, and yoga.

The lowdown

Diet pills are often billed as a quick fix to lose weight, but they can harm your health, even when taken as directed. It’s far better to lose those extra pounds gradually through diet and lifestyle changes.

If you are struggling to lose weight, consult with your doctor. They will be able to offer advice and put you in touch with people who can support you in your weight-loss goals.

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