Butter coffee, often sold as “bulletproof coffee,” is black coffee blended with butter and MCT oil or coconut oil, usually drunk instead of breakfast on a keto diet. It’s filling and creamy, and it fits keto because it contains almost no carbohydrate. But it isn’t a health food. A typical mug made with a tablespoon of butter and a tablespoon of MCT oil contains around 230 calories and roughly 20 g of saturated fat, which is the whole daily limit for women and two-thirds of the limit for men set by the NHS. There’s no good evidence that it boosts weight loss, focus or energy beyond what the caffeine and calories provide. An occasional cup is fine for most people; daily use instead of a nutritious breakfast is harder to justify.
What’s in butter coffee?
The usual recipe is:
- 250 to 350 ml (1 to 1½ cups) of hot black coffee.
- 1 tablespoon (about 14 g) of unsalted butter, often grass-fed.
- 1 tablespoon (about 14 g) of MCT oil or coconut oil.
Everything is blended until frothy, which gives a latte-like texture.
| Ingredient | Calories | Fat | Saturated fat |
|---|---|---|---|
| 1 tablespoon butter (14 g) | about 100 kcal | 11.5 g | 7 g |
| 1 tablespoon MCT oil (14 g) | about 120 kcal | 14 g | about 14 g |
| 1 tablespoon coconut oil (14 g) | about 120 kcal | 14 g | about 12 g |
| Black coffee | under 5 kcal | 0 g | 0 g |
Butter values are calculated from USDA FoodData Central; MCT oil values are typical of product labels, since MCT oil is almost entirely saturated fat.
The claims, checked
“It keeps you full all morning”
The fat does slow digestion, and many people find a butter coffee keeps hunger away for a few hours. But a breakfast with protein and fiber, such as eggs with vegetables or Greek yogurt with nuts, can do the same while providing far more nutrients.
“It boosts weight loss”
There’s no good evidence. A butter coffee adds 200 to 450 calories, depending on how much fat you use. If it replaces a larger breakfast, you may eat less overall; if it’s added on top of your usual food, it can slow weight loss. Weight loss on keto, as on any diet, depends on eating less energy than you use. Our comparison of keto vs calorie counting explains why.
“It raises ketones and improves focus”
MCT oil is converted to ketones more readily than other fats, so it can raise blood ketone levels for a few hours. But higher ketones from a drink don’t mean more fat loss, and there’s little good evidence that butter coffee improves concentration more than ordinary coffee. The caffeine is likely doing most of the work.
“Grass-fed butter makes it healthy”
Grass-fed butter has slightly more omega-3 and some vitamins than standard butter, but it’s still mostly saturated fat. The differences are small.
The downsides
Saturated fat and cholesterol
Saturated fat raises LDL (“bad”) cholesterol in many people. The NHS advises that men should not eat more than 30 g of saturated fat a day and women no more than 20 g. A daily butter coffee uses up most of that before you’ve eaten anything else, and some people on keto see large rises in LDL. A Cochrane review of 15 trials found that reducing saturated fat lowered the risk of cardiovascular events by about 17% over at least 2 years. If you drink butter coffee regularly, get your cholesterol checked. Our guide to keto and cholesterol explains what to look for.
It replaces a nutritious meal
Breakfast is a chance to eat protein, fiber, vitamins and minerals. A butter coffee provides almost none of these, apart from small amounts of vitamin A from the butter.
Stomach upset
MCT oil can cause cramps, diarrhea and nausea, especially in larger amounts or on an empty stomach. Start with a teaspoon if you want to try it.
Caffeine
The FDA says 400 mg of caffeine a day isn’t generally associated with harmful effects in healthy adults. A large mug of strong coffee can contain 150 to 200 mg, so a second or third cup adds up quickly.
Who should avoid it?
- People with high LDL cholesterol, heart disease or a family history of early heart disease.
- People with gallbladder disease or problems digesting fat.
- Anyone pregnant or breastfeeding, who should also keep an eye on caffeine.
- Children and teenagers.
Lighter alternatives
If you enjoy a creamy coffee on keto:
- A splash of cream or whole milk in black coffee adds flavor with far less fat.
- Unsweetened almond or soy milk for a lighter latte.
- Half the usual amounts: 1 teaspoon of butter and 1 teaspoon of MCT oil.
- Have it with food: pair a smaller coffee with eggs or Greek yogurt, so you still get protein and nutrients.
Our guide to coffee on keto covers other options, and our list of keto breakfast ideas has more filling choices.
How to make a lighter butter coffee
- Brew 250 ml of coffee.
- Add 1 teaspoon of butter and 1 teaspoon of MCT oil or coconut oil.
- Blend for 20 to 30 seconds, or use a handheld milk frother, until frothy.
- Add a pinch of cinnamon or a few drops of vanilla if you like.
This version has roughly 80 calories and 7 g of saturated fat, a third of the full recipe.
Common questions
Does butter coffee break a fast?
Yes. It contains calories, so it isn’t a true fast, though it keeps carbohydrate very low.
Can I use coconut oil instead of MCT oil?
Yes. Coconut oil contains some MCTs and is similarly high in saturated fat.
Is butter coffee keto?
Yes. It has almost no carbs. Whether it’s a good everyday choice is a separate question.
Safety note: Keto isn’t suitable for everyone. If you have diabetes, kidney or liver disease, take regular medication, or are pregnant or breastfeeding, talk to your doctor before cutting carbs this far (why it matters).
This article is general information, not medical advice. Talk to your doctor or a registered dietitian before making big changes to how you eat, especially if you have a health condition, take regular medication, or are pregnant or breastfeeding.
