Just about everyone loves coffee.

The get-you-going cup of coffee, first thing in the morning.
The midday pick-me-up cup of coffee (or several of them).
The “I’ve-earned-this” stop at Starbucks for a latte or mocha.
The perfect-ending cup of coffee after a terrific meal.

For the 62% of Americans who drink coffee daily, it would be difficult to imagine making it through a day without at least one cup of joe. The average coffee drinker has more than three per day.

What happens, though, if they decide to try the keto diet? It’s no secret that keto guidelines force most dieters to drastically change the way they eat. Does keto have any effect on the folks who value their coffee even more than they value their ice cream and Big Macs?

Not necessarily. In fact, coffee is one of the best beverages to drink on the ketogenic diet. It provides a lot of health and wellness benefits, too.

But if you’re a “coffee person” getting ready to start keto, there are a lot of “asterisks” to be aware of.

Most don’t involve the coffee itself. The potential issues involve the stuff you like to put into your coffee. 

Let’s dig into the details.

You’re probably familiar with the basics of a keto eating plan. You have to give up most of the “traditionally American” diet staples: fast food, packaged and frozen food, cereal, bread, pasta – and sugar.

What do they all have in common? They all contain lots of carbohydrates, and carbs can easily sabotage a keto diet. The reason is a bit complicated, but once you understand the basic science behind the ketogenic diet, it all makes perfect sense.

• The body needs energy to function, of course. In normal circumstances, it’s generated when the carbohydrates in our diet are burned. The body turns the carbs into glucose (blood sugar), which is the fuel that powers the body and brain.
• The keto diet, however, drastically reduces the amount of carbs you eat every day. A normal adult consumes between 225 and 325 grams of carbohydrates daily; on a strict keto diet, though, you’re limited to 20-25 per day.
• That seemingly-ridiculous restriction has an important purpose. When the body doesn’t get enough carbs to make glucose, it switches to what’s known as a metabolic state of ketosis. In ketosis, the liver produces molecules called ketones – which can be used as fuel in place of glucose.
• Here’s the last part of the puzzle: the body burns stored body fat in order to produce ketones. And fat-burning, as you undoubtedly know, is an important factor in effective weight loss.

So in a somewhat-crazy but interesting way, dramatically limiting carb intake jump-starts the body’s weight loss process. It’s a delicate balance, however. If a keto dieter eats enough carbs to let the body start producing glucose again, they’re “kicked out” of ketosis, their body will no longer burn fat, and weight loss stops.

That brings us to the foods you can’t eat on keto. Some may not contain enough carbohydrates to kick you out of ketosis all by themselves – but when they’re combined with the carbs you “can’t help” eating throughout the day (even lettuce, spinach and eggs contain some carbs), that’s more than enough to end your keto diet.

Sugar is a great example. A single teaspoon of table sugar contains more than four grams of carbohydrates. If you usually take your coffee with two teaspoons of sugar, that’s eight grams right there. And remember, the average coffee drinker has more than three cups per day. Eight grams x three cups = 24 grams of carbs, just in three cups of coffee. Bye-bye, ketosis.

What if you like milk in your coffee? Milk contains lactose, of course, and lactose is nothing more than natural sugar. (It’s often called “milk sugar.”) A normal pour will add another gram or two of carbs to the mix. 

Here’s the obvious conclusion: it’s not coffee that can cause problems. Black coffee contains zero carbs, and is an ideal beverage to drink on keto as long as you don’t drink enough to suffer excess caffeine side effects like the jitters.

Coffee with milk and sugar, though? A single cup can contribute 10 grams of carbs, or half of an entire day’s allowance.

The obvious next step is to figure out if there’s anything keto dieters can put into their coffee, instead of milk and sugar.

This one should be easy, right? There are lots of sugar substitutes, and many are even advertised as being zero-carb.

That’s true, but unfortunately there’s more to the story.

Sugar Alternatives That Contain Carbs

Let’s first rule out two categories of sugar alternatives.

Natural caloric sweeteners, like maple syrup, coconut sugar and honey, are certainly sweet. They’re certainly delicious. But they’re also very high in both carbs and calories, just as the word “caloric” implies. Coconut sugar adds just as many carbs as regular sugar does. Honey adds even more.

So-called “sugar alcohols” (they don’t actually contain sugar or alcohol) like erythritol, xylitol, sorbitol and mannitol are lower in calories and carbs than sugar, and do provide other benefits when used as sugar substitutes. For instance, they have low glycemic indexes, so they don’t spike blood glucose levels and are safe for diabetics.

That’s why sugar alcohols are the sweeteners commonly found in products labeled “sugar-free,” “diet” or “low-calorie.” They’re not really produced for the purpose of sweetening coffee, though; they’re most often used in packaged and commercial products. But more importantly, low-carb – by definition – isn’t as helpful to keto dieters as no-carb.

Artificial Sweeteners

You know all the names, or at least the brand names. Splenda (sucralose), Nutrasweet (aspartame) and Sweet ‘N Low (saccharin) are just three of the most popular artificial sweeteners on the market. Most have been around for decades, in one form or another.

These zero-calorie sugar substitutes all contain very little carb content. In fact, most manufactured sweeteners like sucralose contain zero carbs. However, bulking agents like maltodextrose (which does contain carbs) are added to create a convenient final product like Splenda. These bulking agents ensure that a teaspoon of sweetener is just about as sweet as a teaspoon of sugar, but they’re the reason most artificial sweeteners contain about a gram of carbs per teaspoon.

One gram of carbs is certainly better than the four grams in a teaspoon of sugar, so you’d think that artificial sweeteners are outstanding keto-friendly sweeteners. They really aren’t.

Researchers have found that, in reality, artificial sweeteners are a very bad choice. For starters, it’s been documented that dieters who regularly consume the sweeteners are likely to eat more and to crave real sugar; that’s apparently due to the way artificial sweeteners interact with the brain’s reward centers. Artificial sugar substitutes have also been linked to health risks including diabetes, metabolic syndrome, stroke and dementia.

Since experts recommend staying on the keto diet for only a month at a time, dieters might consider those risks worth taking in return for short-term weight loss. And a decision to just use artificial sweeteners while on keto would be understandable – if there weren’t better alternatives.

Novel Sweeteners

The newest sugar substitutes, known as novel sweeteners, are also the best for keto dieters to use in their coffee.

Stevia (sourced from the South American stevia plant) and monk fruit extract (sourced from the fruit of an Asian gourd) are both all-natural. They’re both incredibly sweet. They’re both calorie-free and carb-free. They both have a zero glycemic index, important to diabetics. They both provide additional health benefits such as lowering cholesterol levels. They both contain lots of antioxidants.

That means they’re zero-carb sugar alternatives that are actually good for you, not simply “not bad” for you. And they’re the perfect choices to add to your morning coffee.