Are Quest Bars Ketogenic Friendly?

This post is part of a series where I estimate a foods effect on ketosis, give it a keto friendly rating, and determine how it fits into a ketogenic diet. Here I cover a low carb and keto dieter favorite, Quest protein bars.


Chocolate Chip Cookie Dough Quest Protein Bar

Keto Friendly Rating:



  • Taste great
  • Ton of flavors
  • Erythritol as primary sweetener which has a glycemic index of zero
  • No red flag ingredients


  • High protein (~20g per bar)
  • Addictive, easy to overeat
  • I recommend adding half of the fiber to net carbs which adds about 7g
  • Soluble corn fibers exact effect on blood glucose still unknown

My Recommendation


Unfortunately, I’ve decided to cut Quest bars out of my diet and I no longer recommend them for a few reasons. For the amount of carbs and protein they have they’re unsatisfying and seem to have an increasing effect on my hunger and sweet cravings. Also immediately after eating a Quest bar I just want another one and if I have more around it takes a lot of willpower not to. But the biggest reason is that there are much better alternatives for that sweet treat fix.

The first being Chocoperfection, it gets a rare 10/10 ketogenic friendly rating, it’s delicious, and there are great flavors just like Quest bars. The only downsides are that it isn’t cheap (but neither are Quest bars) and if you pig out they’ll make you fart up a storm, both prices I’m usually willing to pay.

The second alternative is fat bombs which are incredibly satisfying but don’t taste as amazing as Chocoperfection or Quest bars.

How Quest Bars Can Fit in a Ketogenic Diet

The ideal time to have a Quest Bar is after a heavy lifting or other muscle glycogen depleting activity as the dessert of your post-workout meal. This way you can have a nice workout reward, and not have to worry about the extra net carbs and protein lowering your ketosis because your glycogen deficit should soak up some of your blood glucose.[1]Eating Academy: Ketones and Carbohydrates: Can they co-exist? – Peter Attia, M.D.

A few things to keep in mind are that 20g of protein is nothing to sneeze at, and remember on a low carb diet too much protein can lower and even prevent ketosis by gluconeogenesis,[2]Gluconeogenesis – Wikipedia so you’ll want to adjust your protein intake for the day accordingly. Also to be on the safe side I recommend sticking to the 4g net carb flavors and count half the fiber as net carbs bringing the 4g net carb bars up to 11g net carbs.

Bonus: My Keto Quest Bar Experiment

Since I do my most important work in the morning, and I don’t start eating for the day until after working, my main metric for deciding if a food has a place in my diet is the effect it has on my level of ketosis the next morning.

To find out more about how Quest Bars affect me the day after, I set up a 24 hour experiment in which I tested my blood, breath, and urine ketone levels at 11am while fasted, ingested no calories other than three quest protein bars for the entire day, fasted the next morning and tested my ketone levels again at 11am. The results were that my blood ketones went from 1.6 mmol/L the first day to 1.9 mmol/L the following day.

For more details on the experiment check out the post here.

If you’d like to support me on my keto quest at no extra cost to you please feel free to order any of the products linked on this page or check out the Keto Shop for expertly curated and guaranteed ketogenic friendly products!

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Notes and References   [ + ]

1. Eating Academy: Ketones and Carbohydrates: Can they co-exist? – Peter Attia, M.D.
2. Gluconeogenesis – Wikipedia