Low-Starch Diet for Ankylosing Spondylitis

Medically Reviewed by Tyler Wheeler, MD on December 19, 2022
2 min read

A low-starch diet is getting attention for possible benefits in people with ankylosing spondylitis (AS). One such plan, called the London AS diet, limits starches and focuses on protein and vegetables to help manage inflammation.

While there aren’t many studies on low-starch diets for AS, there is a lot of research on anti-inflammatory diets in general, and some people with the condition say a low-starch diet helps ease their symptoms. Researchers in Portugal plan to test this type of diet in people with AS. Their findings may help show if this way of eating helps to treat the disease.

Here’s the thinking behind this approach. When people with AS eat a large amount of starchy foods, a certain type of bacteria called Klebsiella bacteria in their gut feed on the starch and multiply. This triggers the immune system to respond and make antibodies against the Klebsiella bacteria -- and those antibodies can also attack the joints. This reaction could cause inflammation and worsen your symptoms.

If you eat a lot of starchy foods, that could put your body at risk for more inflammatory activity. For this reason, some people with AS choose to skip those foods or limit the amount of starchy food in their diet.

The gut theory is controversial, the Portuguese researchers note. To test it, they plan to study 300 people with AS for 6 weeks on a diet that cuts their starch by 40% to see how it affects their body, disease activity, and quality of life.

To create meals that are low in starch, cut back on:

  • Bread
  • Biscuits, pastries, or other desserts with flour
  • Pastas
  • Popcorn
  • Rice
  • Grains
  • Starchy vegetables (such as potatoes, beets, and corn)
  • Starchy fruits such as bananas

If you’re eliminating all starches or just cutting back on them, make sure you get nourishment elsewhere. To get the maximum benefit, add wholesome, non-starchy foods to your meals:


It’s best to try a low-starch diet for an extended period so that you can track your AS symptoms. Many people won’t notice a difference in their condition if they use this plan for only a short time.