The Bulletproof Diet Is Anything But

Experts aren't impressed by the regimen. And if you don't like butter, forget it.

According to this diet, you'll shed pounds by kicking your feet up, having a cup of joe and skipping calorie counting.

By Amir Khan

• Is the key to weight loss butter and coffee? Touting that regimen is the Bulletproof Diet, which claims the reason you’re fat, cranky, constantly sick and energy-sapped is because of what you put in your mouth. By overhauling your eating habits and eliminating “toxic” food, diet creator Dave Asprey – a self-described biohacker who spent more than 15 years and $300,000 to hit what he calls "the Bulletproof state of high performance" – promises to have you looking and feeling better in no time, according to his website. But nutrition and medical experts aren't convinced. 

Crack open Asprey's new book,"The Bulletproof Diet: Lose up to a Pound a Day, Reclaim Energy and Focus, Upgrade Your Life," or visit the diet's website and you'll find that foods are ranked on a scale ranging from “toxic” to “bulletproof.” Soy, cheese, wheat, canned vegetables and microwaved foods, for example, are classified toxic, primarily because the diet says they cause chronic inflammation, which it pegs as the cause of weight gain. Onions, kale, almonds and apples are suspect. Coffee, bok choy, coconut, raw foods and yes, butter – particularly butter from grass-fed animals – on the other hand, are bulletproof. The diet alleges that ​by focusing on the allowed foods, loading up on veggies and protein and eliminating carbs, you’ll shed the pounds without having to count calories or exercise.

One of the most controversial aspects of the diet is also its trademark: Bulletproof Coffee – a concoction of coffee mixed with grass-fed butter and either coconut or ​medium-chain triglyceride oil, aka MCT, which is made up of fatty acids said to sharpen the mind. The diet recommends having this ​400-calorie cup for breakfast daily to boost energy, burn fat and halt hunger without the inevitable crash that comes after slugging back your morning java – possible, thanks to its fat-filled additions. ​ 

However, not just any coffee will do. The diet implores you to use coffee low in mycotoxins – toxins produced by yeast and fungi​ that can grow on coffee beans while they're being roasted and (allegedly) causes weight gain, inflammation and other health ​issues. Bulletproof-brand "Upgraded Coffee" purportedly omits mycotoxins, which the diet says abounds in supermarket varieties.

Not exactly, says David Bach​, a Harvard-trained physician and president of New York City's Platypus Institute, a research center that evaluates technologies for optimal human performance. “Mycotoxins themselves are real, but coffee producers are really good at getting rid of [them],” he says. “You don’t have to worry about them in the major supermarket brands, and even if you did, there is no evidence that supports the idea that mycotoxins make you sluggish" or unwell, per other claims. 

That's not to say the entire Bulletproof-coffee concept is bunk. While no studies have evaluated the diet or the coffee specifically, some research published in the past year suggests that MCT oil improves body weight and triggers fat loss​. Grass-fed butter has also been shown to boost​ metabolism, Bach says. “Grass-fed butter is​ very high in conjugated linoleic acid. You find this in all butters, but it’s demonstrably higher in grass-fed butter. There’s a lot of evidence behind the fact that it helps increase your [basal metabolic rate]​,” which is the number of calories your body burns throughout the day.

Colin Darretta​, 30, ​has been​ on the Bulletproof Diet for 18 months. After learning about it from friends, the New York-based founder and CEO of WellPath, a health and wellness startup, decided to try the regimen. The coffee, he says, does live up to (most of) the hype.​ “I’ve found bulletproof coffee to perform largely as promised,” he says. “Some of the hyperbolic statements you hear are overblown. It didn’t make me significantly more energetic or focused than regular coffee, but the effect does tend to last longer. There is also no doubt that it leaves you feeling full , which makes sense when you consider how many calories from the butter and oil you’re actually consuming – well over 400 if you’re taking the suggested serving size.”

One of the biggest challenges Darretta had to surmount when starting the diet was to embrace – not avoid – red meat and high-fat foods. “Up until the past couple of years I did not eat much in the way of red meat or really any sources of cholesterol and saturated fat,” he says. “For the past decade things like butter, egg yolks and all red meat were much maligned as contributors to obesity and cardiovascular disease.”