Fads diets are trendy weight-loss programs and plans that promise dramatic results quickly. But things that sound too good to be true often are. Typically, fad diets result in short-term weight loss, if any at all, and some of these diets can be dangerous to your health.

If you’ve ever tried to lose weight, you’re not alone. Around the world, nearly two out of every five people are trying to lose weight, and nearly 50% of American adults have tried to lose weight in the past year. Only about 20% of those find long-term success in losing weight ‒ which is defined as a 10% reduction in body weight, maintained for at least one year ‒ and fad dieting plays a role in that.

Fad diets often involve removing entire groups of macro- and micronutrients or specific food groups, like grains, fruits, and dairy, or recommend forgoing solid foods entirely. Other fad-diet red flags include:

• Promises of “quick,” “instant” or “overnight” weight loss
• Recommendations based on a single study
• Recommendations made to help sell a specific product or service
• Lists of “good” or “bad” foods
• Recommendations based on outdated information that has been refuted by current, reputable organizations
• Recommendations that don’t account for bio-individuality

Nine Common Fad Diets

Carnivore Diet

The Carnivore Diet involves eating meat or animal products at every single meal, with the aim of consuming zero carbohydrates each day. This diet consists of meat, bone marrow, fish, eggs, butter, organ meats, lard, and bone broth. Some people also eat milk, yogurt, and cheese as part of the Carnivore Diet.

The Carnivore Diet movement is led by Shawn Baker, MD, an orthopedic surgeon. His medical license was revoked in 2017 by the New Mexico Medical Board for “failure to report adverse action taken by a healthcare entity and incompetence to practice as a licensee” but reinstated in 2019 after an independent evaluation.

Eating only meat restricts the amount of fiber (which is important for digestive health) you can get in your diet. Plus diets high in red and processed meats have been linked to an increased risk of developing stomach and colon cancers. The Carnivore Diet can also cause scurvy, a condition that develops as a result of extreme vitamin C deficiency, as singer James Blunt found out after following the diet.

Low- and No-Carbohydrate Diets

The Atkins Diet

The Atkins Diet, or Atkins20, was created by Dr. Robert C. Atkins and is a low-carb, high-fat diet. The diet is split into four phases:

• Phase 1 (induction): Under 20 grams of carbs per day for two weeks. This phase is marked by intake of high-fat, high-protein foods with low-carb vegetables like leafy greens. This kick-starts weight loss.
• Phase 2 (balancing): It’s recommended to slowly add more nuts, low-carb vegetables, and small quantities of fruits back into the diet.
• Phase 3 (fine-tuning): As the person gets closer to their goal weight, they’re instructed to add more carbs until weight loss slows down.
• Phase 4 (maintenance): Healthy carbs are encouraged as tolerated.

The Atkins Diet recommends not exercising, especially during the first three phases. In fact, it claims that exercise isn’t needed for weight loss at all. Low-carb diets like the Atkins diet aren’t sustainable in the long term. Research has shown that “low-carbohydrate diets are unsafe and should not be recommended” and can lead to an increase in coronary heart disease, stroke, and cancer.

The Keto Diet

A ketogenic, or keto, diet is a low-carb, moderate-protein, high-fat diet like the Atkins Diet. When you significantly reduce your carb intake and replace it with fat, your body shifts into a metabolic state called ketosis, where fat is burned for fuel instead of carbohydrates. This process of turning fat into fuel creates substances called ketones.

Normally, you can flush ketones out of your system to exit ketosis, but research has shown that extremely high levels of ketones in the blood can cause ketoacidosis ‒ a potentially life-threatening metabolic disorder usually seen only in those with uncontrolled diabetes.

Paleo Diet

The Paleo Diet, also known as the caveman diet, is based on the idea that humans are meant to eat the way our Paleolithic ancestors did. The theory behind the diet says that modern humans aren’t designed to consume the processed foods that most of us eat, and that’s why instances of obesity and weight-related health problems have risen so drastically.

The diet recommends eating only the things that ancient humans were able to hunt and gather, like vegetables; fruit; nuts; seeds; roots and berries; wild fish; and organic, grass-fed meats. It avoids modern grains (which proponents claim is the source of all autoimmune and chronic inflammation conditions); legumes; dairy products; refined sugars; and processed oils like corn, canola, and soybean oils.

Long-term studies don’t offer much information on the efficacy of following diets like Paleo, but Alex Nelle, RD, says that the diet “has the potential to be a healthy way of eating.” However, the Paleo Diet can put you at risk for developing a deficiency of vitamin D and calcium, both of which are critical for bone health. There’s also the increased risk of developing high cholesterol and heart disease from a diet high in animal products and fat.

Intermittent Fasting

When following an intermittent fasting (IF) diet, food is eaten only during particular times of day. There are several variations of this diet, including:

• 5:2 Method: Five days of eating normally and two nonconsecutive days of restricted calories
• 16:8 Method: 16 hours of fasting and eight hours of eating
• 14:10 Method: 14 hours of fasting and 10 hours of eating
• Alternate-Day Fasting: Eating only every other day
• One Meal a Day: Eating just one meal per 24 hours

Fasting begins when you finish the last meal of the day; but during the fasting period, you can consume zero-calorie drinks like water, tea, and black coffee. Integrative Nutrition Health Coach Jaz Graham recommends – if you’re following an IF schedule – eating foods packed with nutrients, as these can “lessen the need to snack between meals, which can help make IF easier.”

The diet can also be risky for people who have or are at risk of developing an eating disorder, as the time restrictions on caloric intake are a slippery slope. Fasting for long periods can also increase stress levels, disrupt sleep, and increase feelings of anxiety and depression. This diet is also not recommended for people who are on certain medications that must be taken with food.

Cabbage Soup Diet

The Cabbage Soup Diet promises to remove 10 pounds in just a week and includes a little more than just cabbage soup. The bulk of this diet is fat-free cabbage soup, eaten two to three times per day, with other foods allowed each day of the diet.

• Day 1: Fruits, except bananas
• Day 2: Leafy greens but no fruit
• Day 3: Fruits and vegetables
• Day 4: Bananas and skim milk
• Day 5: Beef or skinless, baked chicken and tomatoes
• Day 6: Beef and vegetables
• Day 7: Brown rice, sugar-free fruit juices, and vegetables

This diet doesn’t recommend exercise, as it’s such a low-calorie plan. These types of diets are known as crash diets and won’t help with long-term, sustained weight loss. Cabbage is high in micronutrients but low in calories and is generally a healthy veggie to include in your diet, but the Cabbage Soup Diet calls for such an intense caloric deficit that it can lead to muscle loss and weakness. Plus most of the weight loss is water weight, which you'll regain almost immediately after discontinuing the diet.

Alkaline Diet

The pH scale measures how acidic or basic something is, on a scale of 0‒14, with 0 being the most acidic and 14 being the most basic. Your body’s pH level normally ranges from 7.35 to 7.45, leaning more toward basic. Some studies suggest that an acidic environment allows cancer cells to flourish, but others assert that tumors create an acidic environment, not the other way around.

The alkaline diet claims that some foods ‒ like meat, grains, refined sugar, and processed foods ‒ cause your body to produce more acid, resulting in chronic health issues and the rise of inflammatory diseases. With this diet, it’s recommended to eat only soybeans, tofu, some nuts, seeds, and legumes as well as most fruits and vegetables.

The issue with the alkaline diet and any foods or supplements that claim to change your body’s pH is that your body is very effective already at regulating its pH balance. Food can change the pH of urine but not of blood.

Raw Food Diet

Raw food diets involve eating unprocessed, whole, plant-based, organic foods; followers believe that eating only raw (uncooked) foods can improve health, promote weight loss, and increase energy. There’s some variation in what you can eat on raw food diets, but most include fermented foods; raw and dried fruits and vegetables; soaked and sprouted beans, grains, and legumes; nutritional yeast; and cold pressed oils, like olive oil and coconut oil. They may also include raw eggs, raw fish, raw or dried meat, and nonpasteurized milk and dairy products.

Some research suggests that following a plant-based (but not necessarily raw) diet can improve physical health and prevent disease, and raw foods are higher in water-soluble vitamins like vitamin B and vitamin C. Proponents also believe cooking foods destroys their natural enzymes and that only raw foods are “live.” However, the enzymes present in most foods are denatured by the acid in the stomach, and our bodies already contain the enzymes needed to break down food efficiently.

Raw foods are also more likely to pass on food-borne illnesses like Salmonella, E. coli, and Listeria. The heat applied during the cooking process normally kills these bacteria. Plus cooked foods may be easier to tolerate for those with gut-related conditions such as irritable bowel syndrome (IBS).

Cleanse or Detox Diets

Cleanse and detox diets are short-term diets designed to eliminate toxins from your body, and they typically involve a period of fasting followed by an extremely restrictive diet of juices; smoothies; teas; supplements; and sometimes, laxatives. Many of the foods recommended in cleanses and detoxes are usually sold by the same person who’s promoting the diet – a major red flag.

Is There a “Healthy” Diet?

The best options are often the simplest: prioritizing whole foods and avoiding processed foods as well as those high in saturated fats and sugars. Armaghan Azad, MD, a double board-certified physician in the fields of family medicine and lifestyle medicine (and a Health Coach!) confirms: “The truth is, fad diets don’t work in the long run. My patients are always speechless when they hear those words. Health is a lifestyle, and any beneficial changes we make to the way we eat need to be sustainable. Otherwise, our health suffers.” Dr. Azad suggests following a diet full of real, whole foods.

IIN Grad and Health Coach Lauren Chaunt says that rather than getting caught up in the buzz of the newest fad diet, you should instead “focus on being attuned with your body and nourish it in ways that are conducive to your optimal health.” She recommends that we all “Strive to consume nutrient-dense and colorful whole foods supportive to the microbiome, with a balanced ratio of quality proteins, carbohydrates, and healthy fats that feel best for you. Honor your body’s need for rest, movement, and hydration, while doing your best to regulate stress levels.”

The Bottom Line

Diet programs come in all shapes and sizes, but that doesn’t mean they’re all created equal. Ultimately, which – if any – diet you follow should at best be a jumping-off point for transitioning to a balanced diet full of whole and unprocessed foods. Before beginning any diet plan, make sure to consult your primary care physician to discuss your unique dietary and health needs.