Starch: Pure Evil or Evolutionary Gold?

sweet potatoes

Would eating starch improve your health? Or should we avoid it like the plague? Let’s take a look at this starch paradox and see if it’s a group of foods that might help your health.

A traditional Inuit family eats a day’s worth of food consisting of raw and cooked seafood and fermented foods. Basically, they ate a 0% starch diet and most of their calories came from fat. But they are famous for their lack of chronic diseases like tooth decay, heart attacks, cancer and diabetes. So, that must mean that carbohydrate is unnecessary for good health and might actually be one of the reasons our western populations are so sick right?

Well, let’s take a peek at the meals of a Tukisenta family. The majority of the meal is carbohydrate, mostly starch from sweet potatoes. At an average of 94.6% carbohydrate, it would appear they follow the opposite approach of the Inuit. And yet they have great health, too. This group of people destroys the simple argument that carbohydrate from starch are inherently bad or disease causing.

So what should we make of this starch paradox?

I simply think context is everything. When it comes to real food, the idea of “good” or “bad” is mostly argumentative trickery as the context is what really matters.

The reality is just like cortisol and LDL cholesterol are not inherently “bad” in the body, neither are real foods like potatoes and other forms of starch. As many readers of this blog know, there is a definite subset of people who CANNOT handle starch. I’m going to explore the contextual issues that actually matter in the starch debate.

What is Starch & Where Can You Find It?

Starch is a polysaccharide and specifically forbidden on the Specific Carbohydrate Diet. Starch is a chain of glucose molecules that, depending on the arrangement, can be further characterized into amylose and amylopectin. Amylose is important to note because it’s harder to digest than amylopectin. Due to its structure amylose is called a resistant starch, which means it ends up being valuable as a prebiotic.

In other words, starch is a complex arrangement of glucose molecules and depending on where the bonds are we call it amylose or amylopectin.

Starch is considered the most abundant carbohydrate source in the human diet. Starch is predominately found in three classes of foods:

– Grains & seeds – Wheat, Corn, Rice, Barley, Millet, Oats, Rye

– Root Vegetables – Sweet Potatoes, Potatoes, Taro, Yuca, Parsnip, Turnip

– Legumes – Lentils, Fava beans, Peas, Mung beans, Chickpeas

** this list is not all inclusive **

Starch is really just a bunch of glucose molecules bonded together,  found in most every plant on earth at various times during the growing cycles.

Are All Humans Capable of Eating Starch?

What a fundamental question, yet I hadn’t ever thought to ask it. Luckily, Chris Masterjohn was all over it at AHS 12. As Chris’s presentation shows, humans need to use the enzyme salivary amylase to digest starch. Chris presented studies that showed humans have more copies of the amylase gene AMY1 compared to our nearest ape relatives. And that even in populations who historically eat a low starch diet, they still had several copies of the AMY1 gene.

Chris’s data suggests the more copies of the AMY1 gene a human has, the better they seem to be able to digest starch. This is most likely from an ability to produce more salivary amylase in the mouth. Honestly, the best thing to do is watch the first 8 minutes of this video:

Chris Masterjohn — Oxidative Stress & Carbohydrate Intolerance: An Ancestral Perspective from Ancestral Health Society on Vimeo.

In summary, even if your ancestors didn’t hail from a population who typically ate large amounts of starch, it is likely you evolved to have multiple copies of the AMY1 gene. And these multiple copies should allow you to produce plenty of salivary amylase to digest starch.

How Exactly is Starch Digested?

Starch digestion starts in the mouth with the enzyme salivary amylase. As soon as we start chewing starch, salivary amylase kicks into gear and starts to break down some of the starch into maltose. Maltose is a disaccharide and will require further enzymatic action in order to be split into the monosaccharide glucose, which the body absorbs in the small intestine.

After we swallow the starch and it heads to the stomach, some of the starch will be maltose, but the majority will still need to be broken down. Some of the salivary amylase will still be working on the starch in the stomach until it becomes deactivated by gastric acid.

As the remaining starch moves from the stomach to the small intestine, pancreatic amylase will further break the starch into maltose. At this point, all the maltose will need to be broken down into glucose in order to be absorbed. This happens via a brush border enzyme called maltase, which comes from the villi and microvilli.

Starch digestion is actually more complex than one might imagine. And with so many steps there are plenty of places for problems. Not to mention, as Chris Masterjohn said in his presentation, it appears some of us won the AMY1 genetic lottery and seem to handle starch digestion better than others.

Who Might Want to Eat Starch…

Let’s talk about who might be great candidates to eat starch. People who might consider eating regular starch are those who choose lifestyles that are filled with lots of high aerobic activity. Who are these people?

  • Those spending 5+ hours a week “working out”
  • Cross fitters / high-intensity exercise
  • Endurance athletes
  • Competitive athletes of all types

In other words, these people place high demands on their body on a near daily basis. Robb Wolf has written a great summary of why extra carbohydrates can be very beneficial for these people. Read this series starting with part 1, part 2 and part 3.

Anyone else who doesn’t have one of the problems listed below is a great candidate to give starch a shot and see how it treats them. We all theoretically have the ability to digest it and plenty of groups of people subsist on various levels of starch. I think the key here is to eat the root vegetable forms of starch and not those that include toxins like grains.

Who’s at Risk for Starch Attack!

Just as people who have celiac disease shouldn’t eat wheat, and those with hereditary hemochromatosis should avoid foods high in iron, there are certain groups of people for which starch will not be a good idea.

Insulin Resistant – Diabetics 1 & 2 / Pre-diabetics – Contrary to what the conventional doctors tell diabetics, carbohydrates and starches are toxic to those who have blood sugar control issues. Part of this might be genetic, but in general it’s a really good idea to do some at home testing with a blood glucometer. The fact is if you don’t have good blood sugar control then you need to avoid putting stress on a broken system and eat a low carbohydrate diet.

Small Intestinal Bacterial Overgrowth (SIBO) – Why isn’t starch allowed on SCD? Because SCD is designed to treat those with gut dysbiosis like SIBO. In those with SIBO, bacteria has inappropriately overgrown in the small intestine, and easily feeds on unabsorbed starch and other disaccharides. The digestion of starch is complex enough, that if you have a few mistakes in the process, the small intestine could be overloaded with undigested starch. This creates the conditions for all kinds of bacterial issues just like blood in the water for sharks. It’s not uncommon for these people to not be able to tolerate even a bite of starchy food.

Candida Overgrowth– Candida albicans or any other yeast overgrowth in the gut is a common issue for those dealing with chronic digestive issues. It usually occurs in the small intestine but could also be a body wide overgrowth.  Regardless, Candida predominantly feeds on carbohydrates and so all of the same issues that are present for those with SIBO are problems for those with Candida overgrowth.

Celiac Disease – The last step in starch digestion uses the brush border enzyme maltase to break down the disaccharide maltose into the monosaccharide glucose. At this point the body readily absorbs the glucose. These brush border enzymes are secreted from the small intestinal cells located on the villi. Anyone who has active Celiac disease, by definition, will have sections of partially or completely destroyed (atrophied) villi. This makes it almost impossible for the starch digestive process to happen correctly, making it a good idea for all Celiacs to try not eating starch.

Make sure to read Robb Wolf’s low carbohydrate series above, because those who have Neurodegenerative diseases like Parkinson’s and Alzheimer’s seem to do well avoiding carbohydrates. And certain types of cancers (breast, colon, prostate and some brain tumors) appear to respond very well to very low carbohydrate diets.

But if you don’t have any of these issues, how could you test to see if starch is a good idea?

How to Eat Starch and Check for Problems

Don’t assume starch is perfect for you if you don’t have any of the issues above. Unless you’ve tested it you really don’t know.

We’ve always said that everyone has a custom diet, and part of that is testing whether or not starch is beneficial to your health. Now, whenever you introduce any variable into your diet, you should keep everything else very steady to see if you notice any issues. So, that means don’t try eating out this week or a bunch of new foods in the same week that you test starch. Give it a solid test by keeping the variables as fixed as possible.

Remember that every “type” of starch is its own food. And you might do just fine with sweet potatoes, but not rice. Each type of starch containing food needs to be evaluated.

Here’s an example of how to introduce a safe starch into your diet. Use a food journal and record what you’re eating and how you felt.

Day 1 – 1/2 cup of mashed sweet potato

Day 2 – 1/2 cup of mashed sweet potato at lunch and 1/2 cup at dinner

Day 3 – 1 cup at lunch and 1 cup at dinner

Day 4 – 1 cup with butter and cinnamon at lunch and dinner

If blood sugar issues run in your family, you’re overweight, or you believe you might have some blood sugar control problems, it would be wise to use a blood glucometer to check your post-meal glucose readings to see how your blood sugar responded.

You might not suffer any digestive problems but your blood sugar could spike out of control. If this happens your body is not ready for that type of increased carbohydrate in your diet.

What are “Safe Starches” to Eat

Context is everything when it comes to health and wellness. Each person has a custom optimal diet that is influenced by their genes, epigenetics, lifestyle choices and current health. Starch, for many, is a non-toxic and well tolerated source of nutrition. But for a growing number of people who have blood sugar regulation issues and digestive problems it is best not eaten until these health challenges are overcome. The best answer for almost everyone is to test it.

I think it’s pretty clear from the many populations who eat a large portion of starch each day that it’s quite possible for starchy foods to be part of a health promoting diet. I think the case for starch becomes even more compelling when you trim the foods that contain it to those that are low in toxins and potential inflammatory agents.

This list is being called the “safe starches.” These include the root vegetables like sweet potatoes, potatoes, yuca, taro, parsnips, plantains and white rice.

Tell me about your experience with starch in the comments below.


Did You Like this Article?

Subscribe to our newsletter to receive email notifications, some ways to find relief, and next steps.