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Why bulletproof coffee is not miraculous for weight loss.

Is bulletproof coffee worth all the hype?

The ketogenic diet, coconut oil & bulletproof coffee: what they have in common, and why they’re not miraculous for weight loss

The ketogenic diet and bulletproof coffee are all the rage, the hot topic of discussion on social media and in gyms. Is there any validity to the big bulletproof fad? In this guest post, registered dietitian Lindsay Orbeta, MS, RD, CSSD, gives us some real scientific information on bulletproof coffee, coconut oil and a real ketogenic diet.

Bulletproof coffee and coconut oil are not miraculous for weight loss

My post tonight is the result of a month’s worth of reading peer-reviewed literature in order to accurately address the metabolic effects, mechanism, and impact on weight loss of these three things. But first!

Quick & dirty overview

  • Metabolism during extreme carb restriction = metabolism during starvation
  • No such thing as cyclical ketosis: True, measurable ketosis is like pregnancy: either you are or your aren’t. It takes minimally 33 hours following a clinically controlled, highly carb-restricted diet to achieve ketosis (1.5 mmol/L) and ~3 weeks to become keto-adapted (1.5-3.0 mmol/L)
  • You lose 4-5 lbs the first week on a strict ketogenic diet (KD) and this loss will be 100% from water and 0% from body fat. This is due to glycogen depletion. Every 1g glycogen has 3g water attached to it
  • Drinking BPC & cyclical fasting (in and of themselves) don’t result in ketosis
  • Daily BPC without following a KD does not result in fat loss
  • There are no rigorous studies on bulletproof coffee (“None. not one. And it just tastes terrible. Really”)
  • Coconut oil is only 16% MCT and is NOT primarily made of MCT (medium chain triglycerides), the type of fat human studies have shown to be highly satiating, rapidly converted into a useable fuel, and increase calorie expenditure. Studies on MCT oil cannot be generalized to coconut oil because it’s likely metabolized more like a long chain fatty acid (LCFA), which deposits fat around the body’s vascular system. You’d have to eat obscene amounts of coconut oil to reach the threshold thought to be therapeutic for health or weight loss (that’s just a NASTY coffee)
  • Putting coconut Oil in BPC is not a valid mechanism for weight loss

Ever heard of ‘confirmation bias’? It’s when you start with existing beliefs or expectations (say with a fad diet), go looking for evidence to support it, but ignore any research which contradicts it. It’s sort of like our president-elect’s platform, and it’s also ’bad science’. The utility or disutility for weight loss will be hereby discussed of coconut oil in BPC- with and without following a KD.

Ketogenic diet (KD)

Undoubtedly, coffee, butter, salt and saturated fats are delightful and super-delicious! The KD requires careful measurement of macronutrient ratios, calories, fluids and sodium. It provides 3-4g of fat for every 1g of carbohydrate and protein. For my math-challenged peeps, that’s a ratio of 3:1:1 (fat:carbs:protein). If this sounds complicated and difficult to follow, it is! BUT you can enjoy butter, cheese, heavy whipping cream, mayonnaise, and oils (e.g. coconut or olive), extra sodium and of course – BPC.

Provided your blood sugar remains stable, ketosis is safe. (I do not advocate a KD if you’re diabetic). It’s also true the KD mimics prolonged starvation, where the brain uses ketone bodies rather than sugar as a substrate (fuel). The brain cannot use fatty acids as fuel because fats are bound to albumin in plasma, so can’t traverse the blood-brain barrier1. Muscles (including the heart) can be fueled by ketones (as well as fat). Believe it or not, the heart favors acetoacetate (a ketone body) for fuel over glucose1.

How does a ketogenic diet result in weight loss?

Why we need sugars (carbs) as fuelFirst, understand the primary goal of the metabolic system: It’s to provide sugar to the brain and other glucose-dependent tissues (red blood cells, kidneys) which absolutely require glucose to function. The body has a mandatory, minimal requirement of 50g of carbohydrate/day.

The magnitude of carbohydrate restriction to optimize fat loss varies considerably among people. Generally, less than 50g carbs/day is necessary to elevate ketones above 0.5 mmol/L, the minimal threshold for ketosis.
Keto-adaptation occurs after a period of 2-3 weeks; only then will the body efficiently and consistently burn stored adipose tissue (body fat).

Any side effects?

While you’ll feel sluggish and crazy light-headed for the first few days, you’ll be encouraged by the presence of abs for possibly the first time in your life. Say what? The body retains water when you eat carbs; the water is in glycogen – the stored form of glucose within liver and muscle. Every gram of glycogen is bound to 3-4g of water. Restricting carbs, especially when coupled with a short-term fast from 8pm (overnight) until 2pm the next day, results in glycogen depletion along with water. You’ll lose 4-5lbs in water weight but zero body fat. Rest assured, that weight would return upon abandoning the KD and eating balanced meals.

Longer-term effects of the ketogenic diet

The KD can result in dehydration, kidney stones, constipation, uncertain changes in blood cholesterol and increased risk of bone fractures. Eating more salt than usual is critically important when following a KD, because salt leaves the body along with water after glycogen depletion. If salt is not supplemented, the kidneys retain more sodium and start to waste potassium. This results in a negative potassium balance and reduced plasma volume, causing many of the common side effects (fatigue, fainting, headache, inability to exercise/train). Consuming an extra 1-2g of sodium/day can alleviate side effects.

Coconut Oil

Coconut oil as MCT oil (medium chain triglycerides) is manufactured by processing coconut oil in a lab. MCTs are easily absorbed, head straight to your liver and are elongated there to make immune factors and hormones (prostaglandins). This process is energy inefficient, requiring greater metabolism thus burning more calories. Short term studies in humans show MCT’s significantly increase fat oxidation and thermogenesis (heat production) compared with longer chain fats2. Studies also report greater satiety with MCTs; that people will eat less at a given meal when they replace longer chain fats in their diet with MCTs and this supports their efforts for weight loss3. Athletes consume MCT oil because the fat is rapidly burned (oxidized) and efficiently converted into a fuel source4. All these points form the basis of your weight loss theory for coconut oil (and the theory behind using coconut oil in BPC).

A comparison of the fatty acids in MCT oil and coconut oil

The problem is that the majority of peer-reviewed research compares coconut oil directly to MCTs, and these fats are not only chemically/structurally totally different, but behave differently inside the body and therefore cannot be assumed to have the same health benefits. It comes down to this critical difference: MCT oil is 100% MCFA (medium chain fatty acids) and coconut oil is only 16% MCFA.

Some basic nutritional biochemistry is necessary to understand this point:

Fast-science: Fats are composed of carbon chains, differing in length and number of double bonds. Medium chain fatty acids (MCFA) have 6-12 carbons, and are absorbed into portal circulation (straight to the liver).

Long chain fatty acids (LCFA) have more than 12 carbons and first need to be broken down then packaged into chylomichrons, which travel through peripheral circulation and deposit fat around the body’s vessels.

Importantly, coconut oil is ~half (47%) lauric acid, a 12-C fat. Lauric acid is controversial because research hasn’t concluded weather or not it behaves more like a MCT or a LCFA. Some studies show lauric acid goes to the liver and is quickly oxidized; others report only 25% of lauric acid follows that route.

One small study compared the effect of ingesting 1 oz/day of coconut oil versus soybean oil on abdominal fat in women. While both groups experienced modest weight loss and in comparable amounts, the coconut oil group had a significant decrease in waist circumference, whereas the soybean group gained belly fat. The caveats included a small sample size (40 women) and poor variable control. Subjects were instructed to follow a balanced, low-calorie diet and to walk for 50 minutes each day, but these behaviors weren’t controlled for or well monitored5.

Effect on membrane fluidity

Coconut oil is 92% saturated fat, and because all saturated fats are solid at room temperature, they make our cell membranes more rigid (less flexible). Alternatively, unsaturated fats (e.g, fish oil) are beneficial because they prevent the tight packing of fatty acids within the cell membrane; they have ’gaps’ in their carbon chains, which allow nutrients to get inside the cell. For example, saturated fats can interfere with nerve cell communication via neurotransmitters.

Risk of heart disease

Epidemiologic studies have found an association between whole coconut, coconut cream, and coconut oil and higher levels of HDL cholesterol (the good kind)6. Then again, a 2016 review of literature on coconut consumption and CVD in humans found that coconut consumption also might raise LDL cholesterol, total cholesterol, and serum triglycerides ― so the effect is nullified. The strongest predictor or a heart attack/stroke is your triglyceride to HDL ratio – ideally, the ratio should be less than 1.

One thing is certain: when people replace saturated fat in their diet with mono- and polyunsaturated (e.g, olive oil and fatty fish), they effectively reduce their risk of heart disease. There’s simply no robust proof that coconut oil consistently acts differently from other saturated fats or is better for heart health6.

Science is simply unclear on how the primary type of fat in coconut oil (lauric acid) behaves metabolically. While coconut oil contains nominal amounts of the better-studied 8-C and 10-C MCFAs, you would have to eat obscene amounts of coconut oil to reach the threshold thought to be therapeutic for health or effective for weight loss. The bottom line? Studies on MCT oil can’t be generalized to coconut oil.

Why BPC + cyclical fasting WITHOUT following a KD won’t result in fat loss:

Sleeping 8 hrs IS fasting, so you wake up glycogen-depleted. You’re brain needs glucose but can’t discern that you’re not actually starving. You drink your bulletproof coffee which has MCT oil, butter, coconut oil and caffeine, but wait until 2 pm to eat a balanced meal. You’re hoping you’re using the fat you just drank up as a fuel.

Some less-informed people believe the brain can use fat directly as a fuel. It can’t. Our body readily converts sugar into fat, but we can’t turn fat into sugar. The brain is unable to use fatty acids because they are bound to albumin in plasma and they can’t traverse the blood-brain barrier1.

You're not in ketogenesis just because you drink bulletproof coffeeFat is stored as triglycerides (3 fatty acids attached to glycerol). Glycerol can be freed to combine with another glycerol to create glucose, but not *nearly* enough for your brain. The majority of glucose in this semi-starved, non ketogenic state will come from your body’s protein reservoir: amino acids from muscle tissue. Can you say: self-cannibalization? When the liver converts amino acids into sugar, it’s called gluconeogenesis, and the byproduct is ketones.

The problem is, you’re not starving, nor are you producing nearly enough ketones since you’re not restricting carbohydrate OR protein at respective meals. Your balanced lunch and dinner effectively end any metabolic progress toward ketosis. The minimal threshold for ketosis is 0.5 -1.5 mmol/L, and it takes 33 hrs to 3 weeks compliance on a strict, very-low carb diet in order to produce enough ketones to burn prodigious amounts of fat (scroll up for details). And it’s not just too much carbohydrates ― consuming too much protein (e.g. egg white or lean meat) at the expense of fat further interferes with ketosis, and places unnecessary stress on nitrogen removal from the body.

The wrap-up on bulletproof coffee

So if the brain can *only* use glucose or ketones, what’s fueling you between the time you wake up until your first balanced meal?
Limited glycogen stores from fasting can’t supply sufficient glucose.
The brain can’t use the fat in bulletproof coffee for fuel.
You’re not producing appreciable ketone bodies.
You ARE breaking down muscle, and your liver is converting those amino acids into glucose for the brain.

My advice? Why replace 1 out of 3 nutritious meals of the day with BPC when it’s missing essential nutrients (protein, fiber, vitamin C, iron to name a few) and won’t result in weight loss?

That’s all kids, ping me with questions at: [email protected]

Follow Lindsay on LinkedIn and Instagram,


1. Biochemistry, 5th ed. © 2002, W. H. Freeman and Company
2. St-Onge MP, Jones PJ. Physiological effects of medium-chain triglycerides: potential agents in the prevention of obesity. J Nutr. 2002;132(3):329-332.
3. Dean W, English J. Medium chain triglycerides (MCTs): beneficial effects on energy, atherosclerosis and aging. Nutrition Review website. Published April 22, 2013.
4. Find a vitamin or supplement: medium chain triglycerides (MCTs). WebMD website.
5. Assunção ML, Effects of dietary coconut oil on the biochemical and anthropometric profiles of women presenting abdominal obesity. Lipids. 2009;44(7):593-601.
6. Eyres L, Eyres MF, Chisholm A, Brown RC. Coconut oil consumption and cardiovascular risk factors in humans. Nutr Rev. 2016;74(4):267-280.
7. Wirrell, E. Is a fast necessary when initiating the ketogenic diet? Journal of Clinical Neurology


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