You may have heard of Bulletproof® Coffee, but the Bulletproof Diet is becoming increasingly popular as well.

The Bulletproof Diet claims that it can help you lose up to a pound (0.45 kg) per day while gaining incredible levels of energy and focus.

It emphasizes foods high in fat, moderate in protein and low in carbs, while also incorporating intermittent fasting.

The diet is promoted and marketed by the company Bulletproof 360, Inc.

Some people assert that the Bulletproof Diet has helped them lose weight and become healthier, while others are skeptical about its supposed results and benefits.

This article provides an objective review of the Bulletproof Diet, discussing its benefits, drawbacks and impact on health and weight loss.

Rating Score Breakdown
  • Overall score: 3
  • Fast weight loss: 4
  • Long-term weight loss: 3
  • Easy to follow: 3
  • Nutrition quality: 2

THE BOTTOM LINE: As a cyclical ketogenic diet, the Bulletproof Diet may help you lose weight — especially in the short term. However, it’s not based on solid evidence, cuts out many healthy food groups, and promotes expensive, branded supplements.

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The Bulletproof Diet was created in 2014 by Dave Asprey, a technology executive turned biohacking guru.

Biohacking, also called do-it-yourself (DIY) biology, refers to the practice of modifying your lifestyle in order to make your body function better and more efficiently ().

Despite being a successful executive and entrepreneur, Asprey weighed 300 pounds (136.4 kg) by his mid-20s and felt out of touch with his own health.

In his New York Times bestseller “The Bulletproof Diet,” Asprey tells of his 15-year journey to lose weight and regain his health without adhering to traditional diets. He also claims that you can follow his rubric to achieve the same results (2).

Asprey describes the Bulletproof Diet as an anti-inflammatory program for hunger-free, rapid weight loss and peak performance.

Summary Dave Asprey, a former technology executive, created the Bulletproof Diet after spending years fighting to overcome obesity. The anti-inflammatory nature of the diet is meant to promote fast weight loss.

The Bulletproof Diet is a cyclical keto diet, a modified version of the ketogenic diet.

It entails eating keto foods — high in fat and low in carbs — for 5–6 days a week, then having 1–2 carb refeed days.

On the keto days, you should aim to get 75% of your calories from fat, 20% from protein, and 5% from carbs.

This puts you into a state of ketosis, a natural process in which your body burns fat for energy instead of carbs ().

On the carb refeed days, you’re encouraged to eat sweet potato, squash and white rice to increase your daily intake of carbs from approximately 50 grams or less to 300.

According to Asprey, the purpose of a carb refeed is to prevent the negative side effects associated with a long-term keto diet, including constipation and kidney stones (, ).

The foundation of the diet is Bulletproof Coffee, or coffee mixed with grass-fed, unsalted butter and medium-chain triglyceride (MCT) oil.

Asprey claims that starting your day with this beverage suppresses your hunger while boosting your energy and mental clarity.

The Bulletproof Diet also incorporates intermittent fasting, which is the practice of abstaining from food for designated periods ().

Asprey says that intermittent fasting works in tandem with the Bulletproof Diet because it gives your body steady energy with no crashes or slumps.

However, Asprey’s definition of intermittent fasting is unclear because he says that you should still consume a cup of Bulletproof Coffee each morning.

Summary The Bulletproof Diet is a cyclical ketogenic diet that incorporates intermittent fasting and hinges on Bulletproof Coffee, a high-fat version of regular coffee.

There are no studies examining the effects of the Bulletproof Diet on weight loss.

That said, research indicates that there is no single best diet for weight loss (, , , ).

Low-carb, high-fat diets like the keto diet have been shown to result in quicker weight loss than other diets — but the difference in weight loss seems to disappear over time (, , ).

The best predictor of weight loss is your ability to follow a reduced-calorie diet for a sustained period (, , ).

Thus, the Bulletproof Diet’s impact on your weight depends on the number of calories you consume and how long you can follow it.

Due to their high fat content, keto diets are considered filling and may allow you to eat less and lose weight fairly quickly ().

That said, the Bulletproof Diet does not restrict calories, suggesting that you can reach a healthy weight through Bulletproof foods alone.

Yet weight loss isn’t that simple. Your weight is influenced by complex factors, such as genetics, physiology and behavior ().

Therefore, no matter how “Bulletproof” your diet, you can’t always rely solely on your food intake and may have to make a conscious effort to reduce calorie consumption.

You must also follow the diet long-term in order for it to work, which could be challenging for some people.

Summary There are no specific studies on the Bulletproof Diet. Whether it can help you lose weight depends on how many calories you consume and if you can adhere to it.

Like most diets, the Bulletproof Diet has strict rules that you must follow if you want results.

It encourages certain foods while condemning others, recommends specific cooking methods and promotes its own branded products.

What to Eat and Avoid

In the diet plan, Asprey arranges food in a spectrum from “toxic” to “Bulletproof.” You’re meant to replace any toxic foods in your diet with Bulletproof ones.

Foods classified as toxic include the following in each food group:

  • Beverages: Pasteurized milk, soy milk, packaged juice, soda and sports drinks
  • Veggies: Raw kale and spinach, beets, mushrooms and canned vegetables
  • Oils and Fats: Chicken fat, vegetable oils, margarines and commercial lard
  • Nuts and Legumes: Garbanzo beans, dried peas, legumes and peanuts
  • Dairy: Skim or low-fat milk, non-organic milk or yogurt, cheese and ice-cream
  • Protein: Factory-farmed meat and high-mercury fish, such as king mackerel and orange roughy
  • Starch: Oats, buckwheat, quinoa, wheat, corn and potato starch
  • Fruit: Cantaloupe, raisins, dried fruits, jam, jelly and canned fruit
  • Spices and Flavorings: Commercial dressings, bouillon and broth
  • Sweeteners: Sugar, agave, fructose and artificial sweeteners like aspartame

Foods deemed Bulletproof include:

  • Beverages: Coffee made from Bulletproof Upgraded™ Coffee beans, green tea and coconut water
  • Veggies: Cauliflower, asparagus, lettuce, zucchini and cooked broccoli, spinach and brussels sprouts
  • Oils and Fats: Bulletproof Upgraded MCT Oil, pastured egg yolks, grass-fed butter, fish oil and palm oil
  • Nuts and Legumes: Coconut, olives, almonds and cashews
  • Dairy: Organic grass-fed ghee, organic grass-fed butter and colostrum
  • Protein: Bulletproof Upgraded Whey 2.0, Bulletproof Upgraded Collagen Protein, grass-fed beef and lamb, pastured eggs and salmon
  • Starch: Sweet potatoes, yam, carrots, white rice, taro and cassava
  • Fruit: Blackberries, cranberries, raspberries, strawberries and avocado
  • Spices and Flavorings: Bulletproof Upgraded Chocolate Powder, Bulletproof Upgraded Vanilla, sea salt, cilantro, turmeric, rosemary and thyme
  • Sweeteners: Xylitol, erythritol, sorbitol, mannitol and stevia

Cooking Methods

Asprey claims that you have to cook foods properly to benefit from their nutrients. He labels the worst cooking methods “kryptonite” and the best “Bulletproof.”

Kryptonite cooking methods include:

  • Deep-frying or microwaving
  • Stir-fried
  • Broiled or barbequed

Bulletproof cooking methods include:

  • Raw or uncooked, slightly heated
  • Baking at or below 320°F (160°C)
  • Pressure cooking

Bulletproof Coffee and Supplements

Bulletproof Coffee is a staple of the diet. This beverage contains Bulletproof-brand coffee beans, MCT oil and grass-fed butter or ghee.

The diet recommends drinking Bulletproof Coffee instead of eating breakfast for suppressed hunger, long-lasting energy and mental clarity.

Along with the ingredients you need to make Bulletproof Coffee, Asprey sells several other products on his Bulletproof website, ranging from collagen protein to MCT-fortified water.

Summary The Bulletproof Diet heavily promotes its own branded products and applies strict guidelines for acceptable foods and cooking methods.

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Below is a one-week sample menu for the Bulletproof Diet.

Monday

  • Breakfast: Bulletproof Coffee with Brain Octane — an MCT oil product — and grass-fed ghee
  • Lunch: Avocado deviled eggs with salad
  • Dinner: Bunless burgers with creamy cauliflower

Tuesday

  • Breakfast: Bulletproof Coffee with Brain Octane and grass-fed ghee
  • Lunch: Tuna wrap with avocado rolled up in lettuce
  • Dinner: Hanger steak with herb butter and spinach

Wednesday

  • Breakfast: Bulletproof Coffee with Brain Octane and grass-fed ghee
  • Lunch: Creamy broccoli soup with a hard-boiled egg
  • Dinner: Salmon with cucumbers and brussels sprouts

Thursday

  • Breakfast: Bulletproof Coffee with Brain Octane and grass-fed ghee
  • Lunch: Lamb chili
  • Dinner: Pork chops with asparagus

Friday

  • Breakfast: Bulletproof Coffee with Brain Octane and grass-fed ghee
  • Lunch: Baked rosemary chicken thighs with broccoli soup
  • Dinner: Greek lemon shrimp

Saturday (Refeed Day)

  • Breakfast: Bulletproof Coffee with Brain Octane and grass-fed ghee
  • Lunch: Baked sweet potato with almond butter
  • Dinner: Ginger-cashew butternut soup with carrot fries
  • Snack: Mixed berries

Sunday

  • Breakfast: Bulletproof Coffee with Brain Octane and grass-fed ghee
  • Lunch: Anchovies with zucchini noodles
  • Dinner: Hamburger soup
Summary The Bulletproof Diet emphasizes fats, proteins and vegetables. It encourages drinking solely Bulletproof Coffee for every breakfast.

Keep in mind that the Bulletproof Diet has several drawbacks.

Not Rooted in Science

The Bulletproof Diet claims to be based on solid scientific evidence, but the findings it relies upon are of poor quality and not applicable to most people.

For instance, Asprey cites shoddy data claiming that cereal grains contribute to nutritional deficiencies and that the fiber in brown rice prevents protein digestion ().

However, cereal grains are often fortified with many important nutrients, and their consumption actually increases — not decreases — your intake of important nutrients ().

And while it’s known that fiber from plant foods like rice decreases the digestibility of some nutrients, the effect is rather small and of no concern as long as you’re consuming a well-balanced diet ().

Asprey also provides oversimplified views of nutrition and human physiology, suggesting that people shouldn’t regularly consume fruit since it contains sugar or that all dairy — except ghee — promotes inflammation and disease.

In fact, fruit consumption is associated with weight loss, and dairy products have been shown to have anti-inflammatory effects (, , ).

Can Be Expensive

The Bulletproof Diet can get expensive.

Asprey recommends organic produce and grass-fed meats, stating that they’re more nutritious and contain less pesticide residue than their conventional counterparts.

However, because these items are much more expensive than their conventional parts, not everyone may be able to afford them.

While organically grown produce tends to have lower pesticide residue and may contain greater levels of certain minerals and antioxidants than conventionally grown produce, the differences are probably insignificant to have any real health benefit (, , , ).

The diet also recommends frozen or fresh vegetables over the often more affordable and convenient canned vegetables, despite there being no real health benefit (27).

Requires Special Products

The Bulletproof line of branded products makes this diet even more expensive.

Many of the items in Asprey’s food spectrum that rank as Bulletproof are his own branded products.

It’s highly dubious for any person or company to claim that buying their expensive products will make your diet more successful ().

Can Lead to Disordered Eating

Asprey’s continual classification of food as “toxic” or “Bulletproof” may lead people to form an unhealthy relationship with food.

Consequently, this can lead to an unhealthy obsession with eating so-called healthy foods, termed orthorexia nervosa.

One study found that following a strict, all-or-nothing approach to dieting was associated with overeating and weight gain ().

Another study suggested that strict dieting was associated with the symptoms of an eating disorder and anxiety ().

Summary The Bulletproof Diet has multiple drawbacks. It is not supported by research, can get expensive, requires buying branded products and may lead to disordered eating.

The Bulletproof Diet combines a cyclical ketogenic diet with intermittent fasting.

It claims to help you lose up to a pound (0.45 kg) per day while boosting energy and focus. Yet, evidence is lacking.

It may be beneficial for appetite control, but some may find it hard to follow.

Keep in mind that the diet promotes inaccurate health claims and mandates the purchasing of branded products. Overall, you may be better off following proven dietary tips that won’t be as expensive and will promote a healthy relationship with food.