Why Does My Stomach Hurt After Eating? The Resistant Starch Foods That Changed My Gut Health Story

Gut Health Food Diary journal tracker by Dr. Sharon de Wet

In this article

My gut hurt. Not pain, not cramps — sharp. Aches over my liver area, between my ribs, right side, left side, like someone had set up a drum kit under my ribcage and decided to play shots every time I ate.

No one could tell me why.

Not for lack of trying, and not for lack of tests. Blood work. Stool tests. Parasite screening. Urine. Round after round, and every single result came back normal. I sat across from my doctor and said, as plainly as I could: “There is no way those results match my experience — how I actually feel right now.” I've spent 35+ years in microbiology labs. I know what “normal” ranges mean and what they don't. Normal bloods do not mean nothing is happening. They mean nothing is showing up on that test.

The gastroenterologist's best theory was gallstones. So my gallbladder came out.

The pain stayed.

That's the point where most people either give up or get handed a diagnosis that doesn't quite fit and told to live with it. I did neither. I did what I do professionally, just pointed at myself: I started tracking.

Building My Own Data Set

No app did what I needed. So I built my own tracker — what I ate, when, how I felt in the hours after, where exactly the pain sat, what my bathroom visits looked like, my energy, my sugar cravings, my sleep. Weeks of it. Boring, unglamorous, and the only thing that actually worked.

Bit by bit, a picture I could use started to emerge. Not a diagnosis — a pattern. And patterns, in my world, are where the real answers live.

If you want to run this experiment on yourself, this is the exact tool I built and use: the Gut Health Tracker.

What the Data Actually Showed Me

Sugar in the morning made me dizzy. A sweet start to the day — even something that looked “healthy” — reliably left me lightheaded within the hour. Savoury breakfasts didn't do that.

Cold water hurt. Warm or room temperature water didn't. Every time. Cold water, which I love, caused sharp discomfort within minutes over the liver and stomach area. Warm or room temperature water, nothing. I don't have a ready answer yet — but the pattern was too consistent to ignore.

Kombucha made bathroom visits smooth and easy. Not urgent, not uncomfortable — just easy, which after years of the opposite felt like a small miracle.

Sourdough kept me satisfied for hours. Sourdough contains postbiotics — beneficial compounds produced during fermentation — plus a slower-digesting starch structure. More on the science below.

Cultured butter kept sugar cravings away. Fermented dairy fat changes the fat structure and introduces short-chain fatty acids that influence satiety signalling — the gut-brain pathways that tell your brain “I've had enough.”

The Resistant Starch Discovery

This is the pattern I get asked about the most — and the one with the deepest evidence behind it. So let's actually walk through the science, properly.

What Is Resistant Starch?

Resistant starch is exactly what it sounds like: starch that resists digestion by amylase, the enzyme that normally breaks starch down into glucose in your small intestine. Instead of being absorbed as sugar, it travels intact to the colon (acting more like fibre), where your gut bacteria ferment it — producing short-chain fatty acids, including butyrate, the primary fuel source for the cells lining your colon.

One specific form — retrograded starch, or “RS3” — forms when cooked starches are cooled. The starch molecules recrystallise into a structure your gut enzymes can't easily break down.

Resistant Starch Foods

The everyday foods that reliably contain or develop resistant starch:

  • Cooled cooked potatoes (potato salad, cold roast potatoes)
  • Cooled cooked rice (rice salad, fried rice made from cold rice)
  • Cooled or reheated pasta
  • Cooled oats (and to a lesser extent, freshly cooked oats — see the Practical Advice section)
  • Green (slightly under-ripe) bananas
  • Legumes — beans, lentils, chickpeas
  • Bread specifically made with naturally resistant starch granules or high-amylose flour

I found The One bread, sold at Woolworths or Coles in Australia, which is made with naturally occurring resistant starch granules — my gut feels noticeably calmer on it than on standard bread. I'm not paid to say that; I just noticed it, tracked it, and it held up.

Resistant Starch Benefits

Based on the current human research (see Reference Studies at the end of this article), resistant starch is associated with:

  • Feeding beneficial gut bacteria, which produce butyrate — the primary fuel source for colon cells
  • Steadier post-meal blood sugar and insulin response compared with the same food eaten fresh and hot
  • Improved stool consistency and bowel regularity for many people
  • A lower effective calorie yield, since resistant starch isn't fully digested and absorbed

It's worth being precise here rather than overselling it: the research is genuinely encouraging but still developing, particularly on faecal short-chain fatty acid concentrations, where results across studies have been mixed. I've linked the primary studies at the bottom of this article so you can read the actual data, not just my summary of it.

High Amylose Wheat

Most modern wheat has been bred for very low resistant starch content — under 1%. High amylose wheat (HAW) is a wheat variety selectively bred for a much higher amylose-to-amylopectin ratio, which translates to resistant starch content as high as 11% of total starch — over ten times a standard wheat variety. Human trials using bread and rolls made from high-amylose wheat have shown measurably lower post-meal glucose and insulin responses compared to conventional wheat bread. It's an active area of food science, and one worth watching if you bake your own bread — Kevin has opinions about this too.

Cooled Potatoes, Resistant Starch, and What Actually Happens

Cook a potato, then let it cool fully in the fridge (ideally overnight) — that's when retrogradation is most complete. Cooled and cooled-then-reheated cooked starches both retain meaningfully more resistant starch than the same food eaten hot and fresh. This is the single easiest, cheapest change most people can make: cook once, eat some hot, cool the rest, eat it cold or gently reheated the next day.

Resistant Starch Recipes

Practical ways I've built this into my own kitchen — full recipes linked below:

Practical Advice: What to Eat Today for Breakfast

You don't need a complicated protocol to start. Here's what's actually on my breakfast table:

  • The oats bowl. Made and eaten warm, it still delivers fibre, protein (from the milk), and satiety. Cool leftovers in the fridge and reheat the next day for a modest resistant-starch boost on top. I cook a triple batch of oats, store it in the fridge, and reheat a portion every day. The day I use the last of the stored oats, I cook the next triple batch.
  • Toasted and cooled sourdough. Toasting doesn't remove the resistant starch formed during fermentation and cooling — a slice of Kevin's sourdough, toasted, then left to cool for a few minutes before eating, is a genuinely practical middle ground between “warm comfort food” and “gut-smart choice.”
  • Resistant-starch bread. A slice of a bread specifically made with resistant starch granules (see The One, above), toasted and cooled, stacks the same benefit again.
  • A spoon of cultured butter. On any of the above — this is the piece that, in my own tracked data, made the biggest difference to mid-morning sugar cravings. Another trick, for those that can stomach it: if I feel “snackish” and I know I'm heading for the lolly jar, I have a teaspoonful of cultured butter just like that. It calms the cravings and stills my hunger until dinnertime.

The Recipes

3-Tool Cultured Butter

Real fermented butter, no stand mixer required.

Get the cultured butter recipe here

High-Protein, Naturally Gluten-Free Oats

Serves 2 · 9–10 minutes · Stove, microwave, or Thermomix.

Get the oats recipe here

Kevin's No-Discard Sourdough

A weekly rhythm that actually sticks — no wasted discard, no guesswork.

Get Kevin's sourdough recipe here

Frequently Asked Questions

What foods are highest in resistant starch?
Cooled cooked potatoes and rice, green bananas, legumes, cooled or reheated pasta, and breads made with high-amylose flour or naturally resistant starch granules are among the most practical everyday sources.

Does cooling food actually increase resistant starch?
Yes. Cooking gelatinises starch, and cooling it afterward causes a portion of that starch to recrystallise into a form called retrograded starch (RS3), which resists digestion in the small intestine. Refrigerating overnight produces more than a quick cool-down at room temperature.

What are the benefits of resistant starch?
Research links resistant starch to feeding beneficial gut bacteria that produce butyrate, steadier post-meal blood sugar and insulin response, improved bowel regularity for many people, and a lower effective calorie yield. See the Reference Studies section at the end of this article.

What is high amylose wheat?
A wheat variety bred for a much higher amylose content than standard wheat, resulting in significantly more resistant starch — as much as ten times more than conventional wheat — with measurable improvements in post-meal glucose and insulin response in human trials.

Can I get resistant starch from bread?
Yes, particularly from sourdough (through fermentation and cooling), bread made with high-amylose flour, or bread made with added resistant starch granules, such as The One (available at Woolworths and Coles in Australia). Toasting and then cooling before eating preserves the resistant starch.

Why does my stomach hurt after eating even when my tests are normal?
Standard blood, stool, and urine panels are not designed to catch every functional gut issue — a normal result rules out certain conditions, it doesn't confirm nothing is happening. Structured symptom and food tracking, over weeks rather than days, is often the only way to surface a pattern that standard testing misses. This isn't a substitute for medical care — it's a complement to it, especially when standard tests haven't found an answer.

What to look for when you buy probiotics?
A dedicated breakdown of strain specificity, CFU counts, and label red flags is coming soon — watch the blog for the full guide.

Keep Exploring

Start Your Own Gut Health Tracking

This post shares my personal experience and the patterns I found through self-tracking. It isn't medical advice, and it isn't a substitute for working with your own doctor — especially if you're dealing with pain that hasn't been investigated yet.

Reference Studies

This is not an exhaustive literature review — it's the primary human research underpinning the claims made in this article. Read them yourself; that's the whole point of not just trusting a claim because a blog made it.

  1. DeMartino P, Johnston EA, Petersen KS, Kris-Etherton PM, Cockburn DW (2022). Additional Resistant Starch from One Potato Side Dish per Day Alters the Gut Microbiota but Not Fecal Short-Chain Fatty Acid Concentrations. Nutrients, 14(3), 721. Randomized crossover feeding study; potato-derived resistant starch increased butyrate-producing bacteria, though fecal butyrate itself was unchanged in this trial.
  2. Belobrajdic DP, et al., cited in: An introductory review of resistant starch type 2 from high-amylose cereal grains and its effect on glucose and insulin homeostasis. High-amylose wheat bread lowered postprandial glucose, insulin, and 3-hour incremental AUC responses compared with conventional wheat bread in healthy adults.
  3. Resistant Starch Type 2 from Wheat Reduces Postprandial Glycemic Response with Concurrent Alterations in Gut Microbiota Composition. Double-blind, randomized, placebo-controlled crossover trial (NCT03082131). One week of RS2-enriched wheat rolls reduced postprandial glucose and insulin versus conventional wheat.
  4. High amylose wheat foods: A new opportunity to improve human health. Food science review on formulation and health potential of high-amylose wheat products, ScienceDirect, 2023.
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