How to Eat at McDonald's AND Stay in Ketosis

Most people think that fast food and keto don’t go well together. 

That’s generally true, but guess what? 

If you approach the matter in a smart way, you’ll be able to enjoy a meal at your local McDonald’s without rocketing yourself out of ketosis after the first bite. 

Here’s exactly how. 

The annoying thing about fast food on the ketogenic diet is that you’ll have to be really meticulous with your numbers. To the last gram. 

When it comes to keto, every single carb molecule counts, so keep an eye on them. 

Also, make yourself comfortable with the idea that you’ll be very limited in terms of what you’ll be able to eat. 

That said, let’s jump to action! 

Step 1: Determine your daily carb limit 

To effectively maintain nutritional ketosis, your goal is to get no more than 5% of your daily calories from carbohydrates. But how much would that be, exactly? 

To learn that, you’ll have to start by calculating your Basal Metabolic Rate, which is basically your daily calorie expenditure if you lay in bed all day and do nothing at all. 

For men 

Metric: 

BMR = 66 + (13.75 * weight in kg) + (5 * height in cm) - (6.8 * age in years)Imperial: 

BMR = 66 + (6.2 * weight in pounds) + (12.7 * height in inches) - (6.8 * age in years) 

For womenM

Metric: 

BMR (kcal) = 655.1 + (9.563 * weight in kg) + (1.850 * height in cm) - (4.676 * age in years) 

Imperial: 

BMR (kcal) = 655.1 + (4.35 * weight in pounds) + (4.7 * height in inches) - (4.7 * age in years) 

After doing the calculation above, multiply the result by 0.05 (the maximum daily limit for carbs in percents) to get your number in kilocalories. 

For example, my BMR is 1776 kilocalories, so my daily limit for carbs in order to stay in ketosis is 1776 * 0.05 = 88.8 kcal. 

Pro Tip: If you want your numbers to be even more accurate, you’ll have to adjust your BMR for physical activity. More details in one of our previous articles, How to Calculate Your Macros 

Step 2: Plan beforehand and give yourself about 20% of safe ”carb space” 

Since most meals at any fast-food restaurant have quite a lot of carbs, it’s important to know how much you can allow yourself to eat if you want to stay in ketosis. 

For example, let’s say I eat 85 of my daily carb-kilocalories in the morning at McDonald’s. Perfectly fine, since that’s under my allowed limit. But then let’s say I accidentally go over the remaining 3.8 by eating a perfectly healthy food later in the day, because that minuscule number of carbs is really easy to overlook. Bam, I’m not in ketosis anymore. 

Would that meal at McDonald’s be to blame? Of course not. Would my bad math be? Absolutely. 

The solution is simple: I like to leave myself 20% of remaining carb space, just to make sure I won’t break it with other meals throughout the day. So, out of my 88.8 carb kilocalories, I can eat about 71 on any given day in any fast-food. Since one gram of carbs provides about 4 kilocalories, we’re talking about roughly 18 grams of carbs per day. 

Step 3: Check the restaurant’s nutrition data and pick your meal! 

The only reliable source or nutrition facts regarding the meals at any fast-food restaurant is the said restaurant’s official website (or brochure / poster, if we’re talking about a physical resource.) 

Any other source could have old or inaccurate data. 

Now let’s get to the tasty part and pick something to eat.

You CAN go to McDonald’s without compromising your ketosis. The problem is you’ll have to go through quite a lot of counting calories and planning your meals for that, so see for yourself if it’s worth the trouble. 

Most likely, opting for some healthy meals cooked with high-quality ingredients would be better than eating at a fast-food restaurant, but hey—sometimes you just have to grab a snack on the go. If that’s the case, our recommendation is to pick one of the salads mentioned above and a carb-free drink. This should be enough to help you get home and eat something delicious and keto-safe!