The Bulletproof Diet Review: Does It Work for Weight Loss?

You may have heard of Bulletproof coffee, but the Bulletproof Diet is becoming increasingly popular as well. The company Bulletproof 360, Inc., promotes and markets the diet.

The company claims that the Bulletproof Diet can help you lose up to 1 pound (lb), or 0.45 kilograms (kg), per day while gaining incredible levels of energy and focus.

It’s a keto-style eating plan that emphasizes foods high in fat, moderate in protein, and low in carbs and incorporates intermittent fasting.

The mainstay of the diet is Bulletproof coffee, which is a blend of coffee, grass-fed butter, and medium-chain triglyceride (MCT) oil — ingredients you can purchase on the Bulletproof website.

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

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

DIET REVIEW SCORECARD

• Overall score: 1.9
• Weight loss: 5
• Adherence: 1.5
• Whole body health: 1
• Nutrition quality: 2.5
• Health promotion: 1.5

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

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

Biohacking, also called do-it-yourself biology, involves modifying your lifestyle to make your body function better and more efficiently (1).

Asprey weighed 300 lb (136.4 kg) by his mid-20s and felt out of touch with his health.

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

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

The diet is marketed toward busy people who want to lose weight and improve their focus. In addition to diet, the website focuses on quality sleep as part of weight management, claiming that sleep improves memory, focus, and immunity.

The diet is also geared toward people who can — and want to — purchase expensive diet supplements and sleep aids.

Bulletproof is a keto-style diet, which means that it’s high in fat, moderate in protein, and very low in carbs. While the exact nutrient breakdown varies by the type of keto diet you select, here is a general rubric for sources of calories (3, 4):

• 10% or more from prebiotic fiber
• 50–70% from approved oils and fats
• 20% from approved vegetables
• 20% from approved protein sources
• 5% from approved fruits and starches

The Bulletproof Diet website outlines five types of keto diet that you can try, though it’s worth noting that the macronutrient breakdowns are slightly different in the company’s Diet Roadmap download.

Here are the five options, using definitions listed on the company’s website (5):

• Standard keto diet (SKF): 75% fat, 20% protein, and 5% net carbs (20 grams [g]) per day
• Cyclical keto diet (CKD): same macro breakdown as SKF, but you get a “carb refeed” day once or twice a week, during which you can have 150 g of carbs instead of the usual 20 g.
• Targeted keto diet (TKD): standard SKD with more carbs before a workout to increase energy levels and boost performance
• High protein: 60% of calories from fat, 35% from protein, and 5% from net carbs
• Dirty keto: like the SKF diet but with no restriction around the quality of calories — allows you to enjoy fast food and ultra-processed food items

Regardless of which diet you choose, the foundation of the diet is Bulletproof coffee — coffee mixed with unsalted grass-fed butter and MCT oil.

Asprey claims that starting your day with this beverage suppresses your hunger while boosting your energy and mental clarity. However, there are no clinical studies on Bulletproof coffee to support these claims.

Some forms of the Bulletproof Diet also incorporate intermittent fasting, the practice of abstaining from food for designated periods (6).

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

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

It encourages certain foods while condemning others, recommends specific cooking methods, and promotes the company’s branded products.

What to eat and avoid

In the diet plan, Asprey arranges food in a continuum from best to worst, labeling foods “Bulletproof,” “suspect,” or “toxic” (3, 4).

The diet recommends reducing your intake of “suspect” foods (especially if you have bad reactions to them) and replacing any “toxic” foods with “Bulletproof” ones.

“Suspect” and “toxic” foods:

• Beverages: soy milk, packaged juice, diet drinks, soda, and sports drinks
• Vegetables: corn, canned vegetables, soy, and raw leafy greens
• Oils and fats: oils made from GMO grains (soy, canola, corn), margarine, flax oil, and commercial lard
• Nuts and legumes: soy, soy nuts, corn nuts, chickpeas, lentils, peanuts, flaxseed, and chia seeds
• Dairy: skim or low fat milk, non-organic milk or yogurt, cheese, and ice cream
• Protein: soy, beans, cheese, factory-farmed meat, and high mercury fish such as king mackerel and orange roughy
• Starch: wheat, corn, oats, buckwheat, quinoa, and white potatoes
• Fruit: cantaloupe, honeydew, raisins, dried fruits, jam, jelly, and canned fruit
• Spices and flavorings: commercial dressings, bouillons, and broth
• Sweeteners: fructose, high fructose corn syrup, and artificial sweeteners such as acesulfame potassium

“Bulletproof” foods:

• Beverages: filtered water, green tea, fresh nut milk, and coffee made from Bulletproof Upgrade Coffee beans
• Vegetables: cauliflower, asparagus, lettuce, cabbage, cucumber, zucchini, green beans, and cooked leafy greens
• Oils and fats: Bulletproof Upgraded MCT Oil, coconut oil, pastured egg yolks, grass-fed butter, fish oil, extra-virgin olive oil, and palm oil
• Nuts and legumes: coconut, raw pistachios, almonds, and cashews
• Dairy: organic grass-fed ghee, organic grass-fed butter, and colostrum
• Protein: Bulletproof Upgraded Collagen Protein, grass-fed beef and lamb, pastured eggs, and low mercury fish
• Starch: organic acacia, partially hydrolyzed guar gum, pumpkin, squash, sweet potatoes, and carrots
• Fruit: blackberries, cranberries, raspberries, strawberries, coconut, and avocado
• Spices and flavorings: Bulletproof Upgraded Chocolate Powder, Bulletproof Upgraded Vanilla, sea salt, cilantro, turmeric, rosemary, and thyme
• Sweeteners: xylitol, Bulletproof Mitosweet, erythritol, sorbitol, and stevia

Cooking methods

Asprey claims that you have to cook foods properly to benefit from their nutrients. He categorizes cooking methods as “kryptonite” (not recommended) or “Bulletproof” (recommended). The claim is that toxins form in foods during certain cooking methods.

“Kryptonite” cooking methods:

• deep-frying
• microwaving
• broiling
• barbecuing
• blackening
• charring

While it is true that burning and charring food can create cancer-causing substances known as heterocyclic amines (HCAs), the answer is not to avoid barbecuing or broiling (7).

Instead, use these methods wisely by avoiding exposing foods (particularly meats) to very high temperatures and long cooking times over open flames, removing charred portions of food, and using marinades filled with herbs and spices to prevent HCA formation (7, 8).

The recommendation not to use the microwave is based on the unscientific notion that microwaves create dangerous electromagnetic fields in your kitchen. This is a non-evidence-based scare tactic. The World Health Organization has deemed microwaves safe (9).

“Bulletproof” cooking methods:

• steaming
• baking at or below 320°F (160°C)
• pressure cooking
• boiling or poaching

Bulletproof coffee and supplements

Bulletproof coffee is a staple of the diet. This beverage contains Bulletproof branded 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, the Bulletproof website sells several other products, such as collagen protein, MCT-fortified water, and sleep aids.

Below is a one-week sample menu for the cyclical keto Bulletproof Diet — a standard keto diet plus one “refeed day,” which is higher in carbs.

Monday

• Breakfast: Bulletproof coffee with Brain Octane — an MCT oil product — and grass-fed ghee
• Lunch: avocado deviled pastured eggs with salad
• Dinner: bunless grass-fed burgers with creamy cauliflower

Tuesday

• Breakfast: Bulletproof coffee with Brain Octane and grass-fed ghee
• Lunch: lettuce wrap filled with tuna and avocado
• Dinner: grass-fed hanger steak with herb butter and spinach

Wednesday

• Breakfast: Bulletproof coffee with Brain Octane and grass-fed ghee
• Lunch: creamy broccoli soup with hard-boiled pastured eggs
• Dinner: wild 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

The “refeed” day is higher in carbs than the other days. It includes more foods, such as sweet potatoes, carrots, and berries. The diet recommends that you consume about 150 g of net carbs on carb refeed days.

Sunday

• Breakfast: Bulletproof coffee with Brain Octane and grass-fed ghee
• Lunch: anchovies with zucchini noodles
• Dinner: hamburger soup

No studies have examined the effects of the Bulletproof Diet for weight loss.

However, research indicates that there is no single best diet for weight loss (10, 11, 12, 13).

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 (10, 14, 15).

Keto diets also tend to produce initial rapid weight loss that comes from water loss (16).

The best predictor of weight loss is your ability to follow a reduced calorie diet for a sustained period (13, 15).

Because of their high fat content, keto diets are considered filling and may allow you to eat less and lose weight fairly quickly (17).

That said, the Bulletproof Diet does not restrict calories, suggesting that you can reach your weight loss goal simply by eating Bulletproof foods.

But weight loss is not that simple. Complex factors, such as genetics, physiology, and behavior, influence your weight (18, 19).

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

You must also follow the diet long-term in order for it to work, which could be challenging for some people. It includes many expensive foods and supplements, which are too costly for many people.

Additionally, the Bulletproof Diet has a short list of approved foods, which can make the diet boring and restrictive. This also makes it hard to do in the long term, especially when dining out or during social situations.

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 on are of poor quality and not applicable to most people.

For instance, Asprey cites shoddy and outdated data claiming that cereal grains contribute to nutritional deficiencies and that the fiber in brown rice prevents protein digestion (20).

However, cereal grains are often fortified with many nutrients, and consuming them actually increases — not decreases — your intake of important nutrients (21).

And while compounds from plant foods such as rice do decrease the digestibility of some nutrients, the effect is rather small and is not of concern as long as you’re consuming a well-balanced diet (22).

Asprey also provides oversimplified views of nutrition and human physiology, suggesting that people should not regularly consume fruit since it contains sugar and that all dairy products except ghee promote inflammation and disease.

In fact, research suggests that fruit consumption is associated with weight loss and that dairy products have anti-inflammatory effects (23, 24, 25).

Fruit and dairy are also high in beneficial nutrients that your body needs. Fruit contains fiber, potassium, vitamin C, and antioxidants, and dairy provides calcium and vitamin D. “Bulletproof” dairy products, such as ghee, are not a source of calcium or vitamin D (26).

Can be expensive

The Bulletproof Diet can get expensive.

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

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

While organically grown produce tends to have less pesticide residue than conventionally grown produce and may contain higher levels of certain minerals and antioxidants, the differences are probably not significant enough to have any real health benefit (27, 28).

The diet also recommends frozen or fresh vegetables over canned vegetables — which are often more affordable and convenient — even though all vegetables can provide health benefits (29, 30).

Requires special products

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

Many of the items that Asprey categorizes as “Bulletproof” are his own branded products.

It is 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 foods as “toxic” or “Bulletproof” may lead people to form an unhealthy relationship with food.

This can lead to an unhealthy obsession with eating so-called healthy foods — a condition known as orthorexia nervosa.

A 2022 research review found that following a strict, all-or-nothing approach to dieting was associated with overeating and weight gain (31).

Another review suggests that strict dieting can lead to anxiety and eating disorders (32).

Bulletproof failed Healthline’s medical and business vetting process.

The brand makes unsubstantiated health claims, does not align with Healthline’s approach to nutrition and well-being, and has been subject to multiple warning letters with no response or record of closeout.

In 2020, the company received a Food and Drug Administration (FDA) warning letter for selling unapproved new drugs and adulterated dietary supplements, as well as for violating the current good manufacturing practices (CGMPs) for dietary supplements. There is no response from the company, so the concerns regarding CGMP violations persist (33).

The company also received a 2020 Federal Trade Commission warning letter for making unsubstantiated claims for COVID prevention or treatment. These claims have since been removed from the brand’s site and product marketing (34).

Consumer review are mixed.

Happy customers report that they have lost weight by following the regimen. Some are also satisfied with the quality of the products.

Others shame the company for putting profits over people’s health and say that the supplements are too expensive or of low quality.

If you’re hoping to lose weight or maintain a healthy weight but still want to eat a variety of nutrient-dense foods without a ton of unnecessary rules and restrictions, you might consider trying one of these dietary patterns:

• Mediterranean diet: The Mediterranean diet is rich in vegetables, fruit, whole grains, lean proteins, and heart-healthy fats such as olive oil. This eating plan is associated with weight loss and may help decrease the risk of heart disease and type 2 diabetes (35).
• DASH and flexitarian diets: The DASH Diet and the plant-based flexitarian diet are similar to the Mediterranean diet and are evidence-based, effective ways to manage weight and reduce disease risk.
• Low carb diet: Choose a low carb diet that restricts added sugars and refined grains but encourages consuming carbs from whole grains, beans, vegetables, and fruit. It’s less restrictive than a keto diet and allows a variety of nourishing foods that are considered “toxic” on the Bulletproof Diet, such as nuts, seeds, whole grains, beans, and certain vegetables.

What is the difference between Bulletproof and keto?

The Bulletproof Diet is a high fat keto meal plan with five keto-style diets to choose from. All are high in fat and low in carbs, with slight tweaks and variations.

The biggest difference between Bulletproof and other keto diets is the inclusion of a propriety recipe for Bulletproof coffee, which includes Bulletproof-branded coffee, MCT oil, and butter.

The Bulletproof Diet also includes many branded supplements — such as sleep aids, collagen, greens, and protein bars — that are not part of standard keto diets.

Are eggs part of the Bulletproof Diet?

Eggs are part of the Bulletproof Diet. Specifically, the diet outlines advantages of eating organic or pastured eggs rather than factory-farmed eggs.

Eggs are recommended because they contain fat, protein, vitamin D, choline, and lutein.

The downside is that pastured or organic eggs are more expensive and less readily available than factory-farmed eggs.

Is the Bulletproof Diet anti-inflammatory?

Vegetables, fruits, fatty fish, and nuts are generally believed to be anti-inflammatory foods, while sugar, fast food, saturated fat, refined grains, and highly processed red meats are thought to be pro-inflammatory (36).

The Bulletproof Diet has several iterations and a wide variety of food options. Because some plans may contain more anti-inflammatory foods than others, whether the diet is anti-inflammatory ultimately depends on which foods you choose to eat.

Opting for fatty fish over processed meat, using olive oil instead of coconut oil, and incorporating lots of vegetables are ways to make the Bulletproof Diet more anti-inflammatory.

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

It claims to help you lose up to 1 lb (0.45 kg) per day while boosting your energy and focus. It also relies heavily on the purchase of Bulletproof brand-specific products and supplements.

While it sounds promising and may be effective for short-term weight loss, the diet may be hard to follow because it’s restrictive and expensive.

The diet also lacks research to support its effectiveness and categories foods in a way that can contribute to disordered eating.

For these reasons, Healthline does not recommend the Bulletproof Diet. You’re better off following proven dietary tips that will be less expensive and promote a healthier relationship with food.