The Croissant Diet (TCD) Cheat Sheet

coffee and croissant on table

I posted this up on Reddit and am posting it here again on the Easy TCD site because… I find it very complex to read through all the info on Brad’s Fire in a Bottle site (and it makes me feel a lot less smart than I thought I was 🤔) so I’m trying to make this site the equivalent of “Dummy’s Guide to The Croissant Diet”.

Here’s my summary of what to do. Edited from the original Reddit version due to more now known (6th December 2020).

The Croissant Diet

To do The Croissant Diet, you must seek out only the most saturated fat (SFA) sources, use minimal monounsaturated fat (MUFA) and avoid polyunsaturated fat (PUFA) like the plague.

Brad Marshall

What is the Croissant Diet? It’s a high fat diet which allows starch and carbohydrates and the theory is that the fats used should be very high in long chain saturated fat and a near elimination of vegetable oils – including in foods that have ‘hidden’ vegetable oils such as pork and chicken fat!

The reason it’s called The Croissant Diet (TCD) is that the original inspiration study had rats eating a macronutrient ratio of 18% protein with 40% fat and 42% carbohydrate, with most (85%) of the fat being stearic acid which to the founder of TCD Brad Marshall (who is a French trained Chef) equated to ratios for croissants!

The theory is based on work done by Peter from Hyperlipid.

Backstory of The Croissant Diet in detail can be found on Brad’s Fire In a Bottle site

Stearic Acid – often referred to as “SA” – is the Saturated Fat that helped the rats in the rat study lose fat (and get a 6 pack).

List of Stearic Acid Fats that work for TCD in the table below. Basically you are looking for a ratio of Long Chain Saturated Fats to Unsaturated fats of 0.73 or higher. 

RatioStearic Acid
Coconut Oil2.832.5%
Stearic Acid Enhanced Butter Oil2.5327%
Wild Elk Backfat1.8623%
Cocoa Butter1.5333%
Beef Tallow (USDA)1.0019%
Beef fat from a Ribeye Steak0.8013%
Lard (From a pig I raised, wheat finished)0.73??

Spreadsheet of F/N ratio foods (ie which fats are best for stearic acid)

Do you need to know what F/N is? Not really but if you really want to read up more here’s a link:

(Don’t ask me about it. It’s way over my head!)

And if you want to understand more about fatty acids in a slightly simpler way here’s a good article from Brad –

What To Eat

This is mostly taken from Brad’s “Specification” page but listed here for completeness — I have also created a Quick Start guide for those who want to just get started!

  • Butter
  • Ghee
  • Stearic acid enhanced butter oil
  • Beef Tallow
  • Cocoa butter
  • heavy cream
  • Full fat dairy. Sour cream, Full fat yogurt, full fat cheeses, triple creme.
  • Purified starches like white flour, white rice, masa flour or pasta. Starches do a marvellous job of absorbing saturated fats.
  • Popcorn. Popcorn can absorb a ton of butter! Of course you have to pop it yourself on the stove with butter or stearic acid enhanced butter oil.
  • Peeled potatoes
  • Eggs, especially egg yolks
  • Ruminant meat. Beef, goat and lamb. 
  • Lean Meats like chicken breast or sliced ham.
  • Vegetables sautéed in butter 
  • Organ meats and Pate
  • Seafood
  • Bone broth
  • Head cheese – a terrine or meat jelly often made with flesh from the head of a calf or pig, or less commonly a sheep or cow, and often set in aspic .
  • Dark Chocolate
  • White chocolate (check ingredients!)
  • Zero sugar alcohols like dry wine or whiskey. Sugar free alcohol barely generates an insulin response and it produces ROS and so helps to knock out insulin signalling. Alcohol consumption leads to high levels of free fatty acids – a sign that your mitochondria are in fat burning mode. I want to reiterate that I’m not encouraging anyone to increase their alcohol consumption but if it’s already part of your routine, you can keep it.

Foods to Avoid

  • Commercial Salad Dressing
  • Olive Oil
  • Avocado Oil
  • Avocados and Olives. Did you ever notice that many olives in the US are packed in other vegetable oils? It’s SO misleading.
  • All Vegetable Oils – Soybean, Corn, Canola, Safflower, Sunflower, Hemp, Flax, etc.
  • Mayonnaise
  • Aioli
  • Sauces like ranch dip for crudities that are served at every work lunch and social get together. Also blue cheese dressing at restaurants.
  • Anything Fried or sauteed in a restaurant
  • Nuts
  • Oily seeds like edamame or peanuts.
  • Peanut butter and nut butters.
  • Whole grains. I understand that this flies in the face of conventional wisdom and I’ll get pushback on it. But the fact is the French eat white flour and Chinese and Indian peasants eat white rice. It’s a lot of trouble to convert the whole grains into the purified products. They do this for a reason: removing the bran and germ removes the polyunsaturated fats and lectins from the grains.
  • Low fat dairy. It raises insulin levels and I don’t really see the purpose.
  • Plant based meats. These are inevitably high in vegetable oil.
  • Bacon, (I’m sorry!) lard and pork fat unless you know it was finished on a low fat grain like barley, wheat or peas without using any full fat protein sources such as soybeans. Old fashioned heritage breed hogs have firmer fat but diet trumps everything. If the pig is well finished, the rendered lard or bacon fat will be a firm solid at room temperature. You’ll be able to make a depression in it with your finger but it’ll require some pressure.
  • Chicken fat, which also means skin-on chicken and chicken wings, especially deep fried ones from a restaurant. But even more especially the veggie oil based “blue cheese” they’re served with.
  • Most commercially produced pastries/cookies/crackers. They always seem to find a way to slip some veggie oil in there. Sometimes it’s a small enough amount that you can live with it if the cracker is to be used as a vessel for cheese. If you can find a pure butter croissant from a local baker, you are ahead of the game.
  • Artificial sweeteners. Artificial sweeteners raise insulin levels about as much as sugar does, and the traditional French wouldn’t eat them. If you REALLY need something sweet, why not just use a little regular sugar? Don’t overdo it, of course.

Reading a label

What you are looking for in terms of what to eat.  

Equal amounts of fat and carbs or maybe a little more carbs. More than half the fat is saturated.

In a Croissant the ratio of fat calories to carbohydrate calories is about two to one. 

Fat contains 9 calories per gram – you want half or more of the fat to be saturated. Carbohydrate contains 4 calories per gram, so:

  • Look for the line about Fat and try and make sure Saturated Fat is at least ½ the fat in the product — or make up for it in other foods.
  • Calories from carbohydrates should be equalish to the number of grams of fat.
  • Avoid/minimise PUFAs (polyunsaturated fatty acids)

Brad’s eating rhythm – standard

On day one I would eat a breakfast sandwich – a toasted, buttered stearic-acid-butter croissant with egg, cheese and sausage around 10 am. I’d feel a little hunger pang around 1 pm. It was august and there were a lot of plums around, so maybe I’d eat a plum, which would get my blood sugar back up with a minimal effect on insulin. After that I’d be fine until 7 pm. I’d eat another sandwich, perhaps a toasted stearic-acid-butter croissant with marinara, melted cheese and pepperoni. Sometimes I’d try to eat two but I usually couldn’t get through more than one and a half. On day two I wouldn’t be hungry in the morning so I wouldn’t eat. I’d typically have a “breakfast” croissant around 3pm. 

Brad Marshall

Brad’s Feasting Fasting Experiment

There is a theory if the body thinks it’s feasting and it’s actually fasting then there should be an increase in fat loss! So he is experimenting by eating till super satiated with TCD ratios – for example his croissant sandwiches or pancake fried chicken.

Sample Supermarket bought meal

Based on

  • All butter pastry croissant (check label!), with extra butter, ham and cheese. 
  • Pretzels or crackers (check label) with cheese dip

Stearic Acid Butter

Stearic Acid and Butteroil can be purchased at Fire In a Bottle / Brad’s site –

You can make the stearic acid butteroil yourself – 1) melt butter, 2) add stearic and let it melt, 3) let it cool.