The Truth about John Cisna’s “McDonald’s Diet”

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Disclaimer: The FTC requires me to tell you that I am a brand ambassador for Central Arkansas McDonald’s.  All opinions are my own.

Wait…I thought McDonald’s is the reason American’s are fat?

We’ve all heard it.  We might even believe it.  
Fast food makes you fat.” 
McDonald’s makes teens fat.

But is it true? 

The reality is, it is slightly more complicated of an answer than just yes or no.

I teach teenagers and teenagers love McDonald’s. 

I’ve seen students arrive at school with a bag of McDonald’s food in hand.  After school, I have seen groups of students walking to the McDonald’s that is located about a half mile from our campus. It’s quick, it’s easy and it’s affordable to most teens.

Am I worried about my students love of McDonald’s and fast food?

Again, the reality is, it is slightly more complicated of an answer than just yes or no because I believe it comes down to healthy choices. 


Recently, I was given the opportunity to speak with John Cisna.  He’s a former high school science teacher who has become famous in the last year or so for losing 60 pounds by eating nothing but McDonald’s.  

john cisna

Yes, you read that right. He had a “McDonald’s Diet” meaning that his diet consisted solely of McDonald’s food.

This experiment came about after a discussion with a few of his students.  They set out to see what would happen if Cisna ate nothing but McDonald’s for a 90 day period. Sure this had been done before.  You remember Super-size Me, right? As it turns out, Cisna experienced very different results from Morgan Spurlock. Why?

Well, Cisna attacked this challenge slightly differently by choosing to follow FDA guidelines for caloric and nutrient intake rather than just eat anything off the menu.  Three of Cisna’s students planned out all of his meals by sticking to a  2000 calorie daily diet.  Additionally, the students made sure that they kept withing the FDA’s daily recommended allowance of 15 nutrients.  They did all this by using McDonald’s online meal planner.

After completing the challenge (ultimately going 180 days) and losing about 60 pounds, the media caught wind of his experiment and his life was changed.

Almost immediately, John Cisna found himself traveling the country and sharing his story.  Not unexpectedly, he was met with a lot of criticism, especially when he began touring schools to speak about his “McDonald’s Diet”.

I love McDonald’s but I myself had a hard time understanding how promoting a “McDonald’s Diet” was something that was beneficial.  And then I actually met John Cisna and had a lengthy conversation about the topic.

Here are five things I took away from my conversation with John Cisna.

  1. Kids are eating McDonald’s and it’s important that we teach them how to enjoy it in moderation.
    Cisna promotes regularly making healthy selections like a small order of fries, a side salad or an EggWhite Delight instead of a Big Mac and a chocolate shake which should be reserved as a rare treat. 
  2. The term “McDonald’s Diet” has been grossly misinterpreted and John Cisna  now promotes a lifestyle of eating healthy (which includes McDonald’s, on occasion) rather than touting the benefits of a “McDonald’s Diet”. 
    Cisna advocates for watching your caloric intake and sodium levels and increasing exercise in effort to lose weight.  He admits that McDonald’s worked for him because he monitored these things closely but that is may not work for everyone.
  3. McDonald’s is essentially a grocery store full of choices.
    When you walk into your local grocery store you have a choice between fresh vegetables, fruits and meat and sugar coated cereals, cookies and other “junk” food.  We don’t go around criticising grocery stores because they sell healthy items alongside items that should be considered a treat.  We learn to make smart choices and place foods in our cart that support a healthy lifestyle.  McDonald’s is the same.  When you go in there, there are plenty of healthy items right along side items that should be considered a treat.  No one is forcing you to choose a Big Mac three times a day; we learn to make smart choices.
  4. A balanced diet AND exercise are the key to achieving and maintaining a healthy weight and lifestyle.
    Throughout his experiment, Cisna consulted his doctor and had regular checkups. He used McDonald’s online meal planner along with FDA guidelines to maintain adequate nutrition throughout the experiment.  Cisna agrees that when beginning any lifestyle/diet change that you too should consult your physician and find a plan that works best for you. He also participated in a daily session of exercise which began with just walking but grew to include strength training as well.
  5. John Cisna’s “McDonald’s Diet” wasn’t/isn’t a diet plan.
    When Cisna first started speaking of his success he launched a book called “My McDonald’s Diet” which included 50 days of menus that he used during his experiment.  Cisna made the decision to pull the book because he wanted to promote healthy choices rather than a specific diet plan. His story is simply about making healthy, smart choices.

john cisna speaking

It turns out John Cisna is just a regular guy who had extraordinary results eating only McDonald’s.  He has been met with a lot of criticism but my guess is that he would have seen the same levels of criticism if he had advocated for eating only apples for 180 days.  Cisna promotes a healthy lifestyle not a “McDonald’s Diet”.

So, can you lose weight and get healthy by eating only McDonald’s food? Certainly. If you are making healthy selections and monitoring your sodium and nutrient intake, I am certain you could do that at McDonald’s.  You could also do that at any number of other fast food restaurants.  The key to living healthy is making smart choices no matter where you happen to be eating.

Interested in learning more about healthy choices at McDonald’s? Check out these healthy lunch choices for under 500 calories



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3 thoughts on “The Truth about John Cisna’s “McDonald’s Diet”

  1. Was this so-called experiment videotaped and were there three doctors and a dietitian following his eating schedule. Supersize me shows what total crap and poison that McD’s and more are. Americans need to wake up. The writing isn’t bad, but the conclusions are inaccurate in my view. Take a look at how kids and adults in the US are doing eating this stuff!

    1. Cheryl, you should probably watch “Fat Head” on Amazon Prime before jumping on the anti-McDonald’s band wagon. Many problems with Spurlocker is that he stopped exercising completely, increased his caloric intake by about 2 times (which had the biggest effect) and took over a year to lose the 25 lbs he gained during the month on a strict vegan diet. He could have lost more weight faster on a twinkie diet.

  2. I recall there was the guy in supersize me that ate a big Mac daily and held a record for it. He was in good health which I questioned why they put him in the movie since it didn’t help the agrument. It leads me to believe that it is part genetics and part the amount you consume. Americans eat such large portions which probably came from a era when manual labor was done for everything. I don’t completely disagree with you but I am convinced more and more if you eat less calories and stick with the old tried but true methods of losing weight then you will. It doesn’t have to be organic or Vegan or low carb.

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