Starch 101: Resistant Starch + Keto-Friendly Starch Alternatives
What to Eat

Starch 101: Resistant Starch + Keto-Friendly Starch Alternatives

#1 Low Carb & Keto Diet App Since 2010

Track macros, calories, and access top Keto recipes.

Download on the App Store
Get in on Google Play

Starch 101: Resistant Starch + Keto-Friendly Starch Alternatives

Posted 4 years ago

Brian Stanton

Brian Stanton


Ari Magill, M.D.

Ari Magill, M.D.

Scientific Reviewer

Expert Approved

Going Keto means cutting carbs from your diet. The forbidden carbs fall into two main categories: sugar and starch. 

This article is about starch. Starch, which is just a cluster of sugar molecules, is found in foods like rice, bread, pasta, potatoes, yams, and carrots. 

Since the Agricultural Revolution about 12,000 years ago, starch has dominated the human diet. Once we started growing crops, we hung up the hunting spears. 

But 12,000 years is nothing in evolutionary terms. In the millions of years before agriculture, hominids evolved to flourish without a steady supply of carbs. 

We evolved, in other words, to cycle in and out of ketosis. That’s how our ancestors stayed lean and metabolically flexible. 

Taking a break from starch can help you activate your fat-burning machinery too. 

Today you’ll learn what starch is, why it’s prohibited on the Keto diet, and how to replace starch with low-carb alternatives. Read on. 

What Is Starch?

Starch is a type of carbohydrate, the primary way in which plants store energy. 

Plants form carbs via photosynthesis and store them as starch and sugar. Animals eat plants and store the digested sugar (glucose) as glycogen.  

Starch is made up of molecules called polysaccharides.[*] In layman's terms, this means that starches are made of chains of sugar molecules.

That sugar molecule is called glucose. It’s the same molecule that arrives in your blood as blood sugar (blood glucose) when you digest starch. 

The two main starch molecules are called amylose and amylopectin. (They’re just chains of glucose). When you eat amylose or amylopectin, an enzyme called amylase breaks them into glucose for easy absorption through the small intestine.[*]

Foods high in starch include corn, rice, bread, pasta, cereal, wheat, oats, potatoes, sweet potatoes, and apples. If it’s high in carbs and not especially sweet, it’s going to be high in starch.  

Not all starch, however, is absorbed through the small intestine. Any unabsorbed starch is called resistant starch.[*

Unripe bananas, cooked and cooled potatoes, and cooked and cooled rice are a few examples of foods high in resistant starch. This type of starch is considered a dietary fiber because it adds no calories and passes through your gut mostly undigested.[*][*] It only feeds your gut bacteria, and is likely beneficial for gut health.  

Because it’s non-caloric, resistant starch isn’t technically off-limits on Keto. However, that’s not a license to indulge in piles of mashed potatoes. Because regular starch—which IS off-limits on Keto—almost always comes along for the ride.

Why Starch Isn’t Keto

Limiting carbs on Keto nudges your body into fat-burning mode. But why does this happen?

It happens because limiting carbs keeps blood sugar low. And low blood sugar, in turn, keeps the hormone insulin low. 

When insulin is low, your body sends out a memo: 

Dear cells, I have news: insulin is low. This means that usable energy is probably low. Start breaking apart body fat immediately. Then send those fatty acids to the muscles for energy and to the liver for ketone production. No need to reply, just get to work. 

-The body

Your cells get the memo. That’s how ketosis happens.[*] That’s how you fat-adapt.

But if you’re constantly eating starch—if you’re constantly introducing glucose into your digestive system—blood sugar and insulin never drop low enough to send the fat-burning signal. 

Instead, high insulin sends the opposite message. It sends the message to store fat.[*]

Fortunately, there are ways to enjoy the gustatory pleasures of starch without the glycemic impact. 

Starch Alternatives

If starch curtailment has taken your favorite foods off the menu, don’t despair. There are a variety of Keto-approved alternatives for baking and munching. 

Almond flour

Almond flour is created from skinned, blanched, and ground almonds. High in fat (12 grams), moderate in protein (5 grams), and low in net carbs (2 grams) per quarter cup, almond flour is more Keto-friendly than most flour alternatives. 

Why not whip up a batch of these delicious Keto Tahini Chocolate Chip Cookies.

Those with nut allergies or sensitivities, however, should steer clear. If this sounds like you, consider other low-carb flours like sunflower seed meal, pumpkin seed meal, and flax meal. 

Coconut flour

Made from dehydrated coconut meat, coconut flour is great for baking on Keto. Try our Keto Paleo Coconut Sponge Cake in a Mug for a quick and tasty treat.

A quarter cup of coconut flour contains 6 grams of protein, 3 grams of fat, and 7g of net carbs. Coconut flour is also rich in lauric acid, a type of fat with potent antimicrobial activities, particularly against pathogenic bacteria.[*] Lauric acid is often used to fight infections in the gut and elsewhere. 

Cauliflower (and cauliflower rice)

Rice is one of the hardest foods to quit when you switch to Keto. It’s ubiquitous, multi-functional, and—if you prepare it properly—a real pleasure for the taste buds. 

That’s where cauliflower rice comes in. If you haven’t tried it yet, you’ll be surprised how similar it is to white rice in taste and texture. 

Cauliflower rice is fairly easy to prepare. Simply cut up the florets (not the stems) by hand or with a food processor, squeeze the raw rice into a paper towel to remove the moisture, and cook in a pan (5 minutes) or microwave (3 minutes).

Or save time and nuke a bag of frozen cauliflower rice. Nobody will judge!

With only 3 grams of net carbs per cup, cauliflower rice fits nicely into your Keto diet. Plus cauliflower contains a variety of molecules (like sulforaphane) currently being studied for their anti-cancer properties.[*]

To impress your family, try this Low Carb Lime and Coconut Cauliflower Rice for dinner this week. Don’t expect leftovers.   

Thickening Agents

If you love cooking, you’re probably used to recipes that call for cornstarch as a thickening agent. But cornstarch is typically forbidden on Keto, with a whopping 116g of net carbs per cup. That’s enough to knock you and your 5 best friends out of ketosis. 

Luckily, there are a variety of Keto-friendly cornstarch alternatives. 

These include:

  • Xanthan gum
  • Chia seed
  • Flax seed
  • Potato starch (occasionally and in moderation)
  • Tapioca fibre
  • Glucomannan
  • Psyllium husk
  • Guar gum

All of these are low in net carbs and high in fiber. Some, like xanthan gum, can be substituted 1:1 with cornstarch, making your life as a Keto cook that much easier. 

Squash or Zucchini Pasta

Pasta craving? Spaghetti squash and zucchini noodles are here for you. 

Both are low in net carbs and are much lighter than, say, a plate of rigatoni. You won’t feel like Earth’s gravity just doubled as you glide (not stagger) from the dinner table. 

To get you started, here are some recipes and resources from the Carb Manager Kitchen:

One last bonus: zucchini and spaghetti squash are good sources of vitamin B6, vitamin C, and fiber. Good deal.

A Starch-Free Keto Diet

You can’t eat starch on Keto, but you can still eat foods that taste, feel, and delight like starch. 

Hankering for bread? Try this Keto Seeded Loaf.

How about a Low Carb Spanish Cauliflower Rice

The possibilities are only constrained by your imagination. What will you make next?

Comments 4

  • FabulousCauliflower275214

    FabulousCauliflower275214 2 months ago

    But although cornstarch may have a "whopping 116g" of net carbs per cup as you say, most recipes only require a tablespoon or two, and when that is divided among 6-8 servings the carb count ends up being low. I'm also confused why you recommend potato starch as an alternative when it typically has more carbs than cornstarch.

    • Mshive

      Mshive 4 months ago

      What should I do when starch is the only thing that ever makes me feel full? (i.e. roasted potatoes and popcorn) My body never communicates fullness with any other food, high in fat or otherwise.

      • StellarKetone832524

        StellarKetone832524 4 months ago

        Please include some articles about tracking macros for resistant starch.

        • Boatson

          Boatson 2 years ago

          Reference: " Any unabsorbed starch is called resistant starch.[*]" from this article is there a plan that in the future Carb Manager could distinguish and account between starch and a resistant starch? Specifically, in the future could Carb Manager have different values for xx grams of rice that was cooked and refrigerated overnight from rice that was served while still hot from being cooked?