The ketogenic diet is one of the strictest eating regimes out there.
However, it doesn’t mean you won’t be able to enjoy snacking at a fast-food restaurant every once in a while if you want to stay in ketosis.
Yes, it will be a tricky task, but not an impossible one.
In this article, we’ll take a look at how exactly you can treat yourself to a meal at Burger King without canceling all your keto-related efforts with the wrong choices.
By the way, we have a similar article on eating keto at McDonald’s, if that’s what you prefer.
The only trouble about enjoying a fast-food meal on the ketogenic diet is to stay under your daily carb limit. After all, we’re talking about a measly 5% of all your daily calories—that’s your maximum of carbs on any given day.
If you’re able to limit yourself to that and get plenty of healthy fats at the same time, there’s no problem in going to Burger King whatsoever.
Here’s a quick recap of the step-by-step process you’ll have to go through.
Step 1: Determine your Basal Metabolic Rate (BMR)
Your BMR reflects the amount of energy (in kilocalories) you will burn on any given day if you decide to spend it in bed, without indulging in any activities.
One of the most accurate ways of calculating your BMR without using a dedicated app is to use the Harris-Benedict equation, which goes like this:
Metric:BMR = 66 + (13.75 * weight in kg) + (5 * height in cm) - (6.8 * age in years)
BMR = 66 + (6.2 * weight in pounds) + (12.7 * height in inches) - (6.8 * age in years)
BMR (kcal) = 655.1 + (9.563 * weight in kg) + (1.850 * height in cm) - (4.676 * age in years)
BMR (kcal) = 655.1 + (4.35 * weight in pounds) + (4.7 * height in inches) - (4.7 * age in years)
For example, a 27-year-old man with a height of 182 cm and a weight of 85 kg would have a BMR of 1961 kilocalories per day.
Step 2: Adjust for physical activity
The BMR reflects the number of calories you’d burn without engaging in any sort of activity, but that’s a rare attitude. Unless you are in a deep coma, you’ll still walk around, do some chores around the house, maybe go for a walk, etc.
To account for these extra energy expenses, the next step is to adjust your BMR for physical activity. The resulting number is known as Total Daily Energy Expenditure (TDEE). This step is somewhat optional but will allow you to approach the matter more accurately—and allow yourself to eat more carbs without compromising ketosis.
Little to no physical activity (1-2 workouts/week) - BMR * 1.38
Sedentary job, occasional walks and activities outdoor, non-regular physical activity.
Regular physical activity (3-5 workouts/week) - BMR * 1.55
Several workouts per week with a lot of time sitting in one place between them (be it at work, home, in one’s car, or anywhere else)
Heavy physical activity (6-7 workouts/week and/or manual labor as one’s main job) - BMR * 1.72
People with a physically active job and/or a strenuous workout routine on the side. Alternatively, physical exercises may be their primary job, like in the case of professional bodybuilders and athletes.
For example, let’s say the man from our previous example goes to the gym 3 times per week. Therefore, his TDEE would likely be around 1961 * 1.55 = 3040 kilocalories.
Step 3: Estimate maximum carb intake
Knowing your daily calorie limit is useful, but you’ll need to know how many carbs you can fit into that—and what part of this carbs you can allow yourself to eat at a fast-food restaurant.
Since you can eat just 5% of your daily calories from carbs on keto, the first step is to multiply your TDEE by 0.05 to get the number of calories you’d be allowed to get from carbs on any given day. To convert these kilocalories into actual grams of carbohydrate, divide it by 4 since your body burns one gram of carbs for about 4 kilocalories.
For example, if the TDEE of our imaginary man from the previous example is 3040 kilocalories, 5% of them would make about 152 kilocalories - that would be the amount of energy he’d be allowed to get from carbs every day. This makes about 38 grams of carbs (152 / 4 = 38).
Step 4: Plan beforehand and leave space for mistakes
The Pro Tip when eating fast food on keto is to never get all of your allowed carbs from fast food, as this would leave you with no room for possible mistakes.
For example, let’s say the man from our example gets his 38 grams of carbs (or even a bit less than that, like 35 grams) with his meal at Burger King. In theory, that would allow him to stay in ketosis, but then he’d have only 0-3 ”safe” carbs before he reaches his limit. A bowl of salad, then, could compromise his ketosis.
To avoid this silly situation, a wise idea would be to get no more than 80% of your daily carbs from fast food and leave the remaining 20% just in case.
For example, the man from our example would then have to eat no more than 38 * 0.8 = 30.4 grams of carbs with his meal at Burger King.
Step 5: Look through the restaurant’s nutrition data
This step is simple: just find the restaurant’s official nutrition facts and check what foods you’ll be allowed to eat without breaking your calculated carb limit.
Let’s try this using the imaginary man from our example and the meals at Burger King (USA).
So, our goal now is to use the official Burger King (USA) nutrition facts to find meals with no more than 30 g of carbs.
Hamburger - 26 g
Cheeseburger - 27 g
Double Hamburger - 26 g
Double Cheeseburger - 27 g
Bacon Cheeseburger - 27 g
Bacon Double Cheeseburger - 27 g
Chicken Nuggets (4 pieces) - 11 g
Chicken Nuggets (6 pieces) - 16 g
Chicken Nuggets (10 pieces) - 27 g
Spicy Chicken Nuggets (4 pieces) - 11
Spicy Chicken Nuggets (6 pieces) - 17 g
Spicy Chicken Nuggets (10 pieces) - 28 g
Crispy Chicken Tenders (2 pieces, no sauce) - 22 g
Chicken Fries (9 pieces) - 20 g
Salads & Sides
Garden Chicken Salad with Grilled Chicken (no dressing) - 16 g
Club Salad with Grilled Chicken (no dressing) - 16 g
Garden Side Salad (no dressing) - 3 g
Ken’s Ranch Dressing - 2 g
Ken’s Golden Italian Dressing - 4 g
Ken’s Lite Honey Balsamic Vinaigrette - 14 g
Onion Rings (value) - 19 g
Croissan’Which® Egg & Cheese - 29 g
Croissan’Which® Sausage, Egg & Cheese - 30 g
Croissan’Which® Ham, Egg & Cheese - 30 g
Croissan’Which® Bacon, Egg & Cheese - 30 g
Ham, Egg & Cheese Biscuit - 29 g
Sausage, Egg & Cheese Biscuit - 29 g
Bacon, Egg & Cheese Biscuit - 29 g
Sausage Biscuit - 28 g
Breakfast Burrito Jr. - 27 g
Hash Browns (small) - 24 g
Diet Coke - 0 g
Unsweetened Tea - 0 g
BK® Café Coffee - 0 g
Attention! No dressings / sauces are allowed besides the few ones we specified above. This is important, as they often come with an awful amount of carbs, so stay alert.
Examples of meal combinations
Hamburger + Garden Side Salad (no dressing) + Diet Coke = 29 g
Bacon Double Cheeseburger + Unsweetened Tea = 27 gGarden Chicken Salad with Grilled Chicken + Ken’s Ranch Dressing + Chicken Nuggets (4 pieces) = 29 g
With a bit of planning beforehand, you can go to Burger King without messing up your ketosis. Just keep in mind that every gram of carbs counts, so double-check your numbers before actually going out for that delicious snack.