Yes, onions are keto friendly. However, like all foods, they are keto friendly in the correct portions. Most recipes will use onions in serving sizes that won’t result in you breaking keto.
Onions range from 5 net carbs per cup to 24 net carbs per cup, depending on the type of onion. Now, keep in mind, the amount you will consume per serving will be a fraction of a cup.
Why such a wide net carb range? Because there are eight different types of onions, each having varying net carb value. There are red onions, leeks, Vidalia onions, pearl onions, white onions, yellow onions, green onions (scallions), and shallots.
Shallots have the highest net carb content, and green onions have the lowest. When I find a recipe containing shallots, I always replace them with green onions. Out of all the onions, green onions are most similar to shallots. They have a similar mild profile and are nothing like their tear-producing cousins.
Why Onions are Good for the Keto Diet
One of the biggest challenges of the keto diet is getting enough fiber. The average person needs 25 grams of fiber per day. A lot of ketoers avoid vegetables because of their carb content. Keep in mind, though, the goal isn’t to completely eliminate carbs. The goal is to manage to a net carb number.
If you don’t get enough fiber, you’ll be plagued with bathroom problems, i.e., constipation. And that, my friends, is one of the most common problems with a keto diet that isn’t well-balanced. So, the way to correct it is to make sure you get enough fiber in your keto-loving diet. Keto friendly vegetables are the easy and nutritious way to do it.
How Many Carbs are in Onions?
There are wide variations in the carb content of onions, with shallots having the most and green onion having the least net carbs.
Here’s a quick comparison of the macros of each type of onion. However, I’ll go over each one individually in the section below.
Macros and Net Carbs in Red Onions
One cup of red onion contains .1 gram of fat, 14 net carbs, 2.2 grams of fiber, and 1.5 net gram of protein. I use red onions in my pea salad recipe and also in my bbq chicken pizza recipe. For the most part, red onions add a good flavor when used raw or as a topping.
Macros and Net Carbs in Leeks
One cup of leeks contains .2 grams of fat, 6.9 net carbs, 1 gram of fiber, and .8 grams of protein. I’ve never cooked with leeks, but given the macro profile and low net carbs, it’s now definitely on my list of things to try.
Macros and Net Carbs in Vidalia Onions
One cup of Vidalia onions contains .1 gram of fat, 10.6 net carbs, 1.4 grams of fiber, and 1.3 grams of protein. While Vidalia onions are known for being sweet, they are still keto friendly in the right portions.
Macros and Net Carbs in Pearl Onions
Pearl onions certainly aren’t as keto friendly when compared to their super low carb cousins, leeks, and green onions. However, this doesn’t make them a no-no on the keto diet.
One cup of pearl onions has .3 grams of fat, 15.4 net carbs, 2.6 grams of fiber, and 2.5 grams of protein.
Macros and Net Carbs in White & Yellow Onions
White and yellow onions have the same macro and net carbs. I use them interchangeably in my recipes. One cup of yellow or white onions contains 0 grams of fat, 9 net carbs, 1 gram of fiber, and 1 gram of protein.
Macros and Net Carbs in Green Onions
Green onions have a delicate, mild flavor and are an excellent substitute for shallots. I use them in my keto chicken marsala recipe.
One cup of green onions has .2 grams of fat, 4.7 net carbs, 2.6 grams of fiber, and 1.8 grams of protein.
Macros and Net Carbs in Shallots
Shallots can be keto friendly. However, I avoid them because they can easily be swapped with green onions. Using green onions in place of shallots reduces the carb content by 75%.
One cup of shallots contains 0 grams of fat, 24 net carbs, 2 grams of fiber, and 4 grams of protein.
Conclusion - Onions are Keto Friendly
Onions can be keto friendly if consumed in appropriate quantities. They’ll give you a healthy dose of fiber, which is essential on the keto diet. It’s probably better to stay away from shallots and choose green onions instead.