Portion Size Matters on the Low FODMAP Diet

I receive numerous questions weekly about portion sizes and the low FODMAP diet. Portion size does matter on the low FODMAP diet.  Strawberries, for instance, are low FODMAP but NOT low FODMAP if you eat a full bowl the size of your head of them!

Make portion control more inviting…such as serving low FODMAP fruit kabobs! You can serve these cute kabobs with lactose free vanilla yogurt as a dipping sauce. 1 or 2 kabobs are a nice healthy treat.fruit kabobA very useful resource regarding portion control for the low FODMAP diet can be found at Monash University’s FODMAP blog here.

The Monash Uni low FODMAP app serves as another portion control resource.  Remember that 20 blueberries is a serving of fruit for the low FODMAP diet but you CAN eat multiple servings of fruit per day. Limit to the 20 blueberries at one meal but allow yourself another low FODMAP fruit at the other meal or snack times, if you desire. If you choose to have 20 blueberries at breakfast and want to have 20 blueberries with dinner..that is OKAY! Making a fruit smoothie can work on the low FODMAP diet but remember to add the equivalent of one fruit serving.  This could be 1/2 of a medium banana and 5 strawberries.

Oatmeal is a wonderful grain–rich in fiber.  But the portion size is just 1/4 cup dry or 1/2 cup cooked per meal.  Again, you can eat oatmeal multiple times during the day, but limit the portion size while on the elimination diet. When experimenting and learning more about your personal FODMAP tolerance, you can try adding more oats to your meal.  If 1/2 cup of oatmeal is not enough to fill your tummy, consider adding quinoa flakes to the mix so you can indulge in a larger bowl of hot cereal for breakfast….without the bellyache.

Tolerance to FODMAPs is very individual— listen to your body and experiment with low FODMAP foods. Despite the low FODMAP serving of 20 blueberries, You may find you can tolerate 30 blueberries without any tummy distress.  If so, eat 30 blueberries as your serving size once you are done with the elimination phase and have a good sense of how the low FODMAP diet is helping your symptoms. Conversely, you may find 10 blueberries is the right amount for you, then stick with the lower number.

Protein foods such as plain beef, chicken, fish and eggs are FODMAP free,  if you are particularly hungry perhaps choose a larger portion of these naturally low FODMAP foods. Rice and white potatoes are very low FODMAP too–so if you need a few more bites–go with an extra scoop of these starchy foods.

I find most of my patients do very well on the low FODMAP diet when they eat a balanced meal full of low FODMAP foods.  What’s a well-balanced low FODMAP meal? Well for starters, choose a carb rich low FODMAP option such as a baked potato, 1/2 sweet potato, quinoa or brown rice, add a protein option such as firm tofu, peanut butter, hard cheese, chicken, fish, lean beef or pork and adding a serving of  low FODMAP veggies, one serving of low FODMAP fruit and of course, a smattering of healthy fats such as chia seeds, pumpkin seeds or a drizzle of olive oil. {Of course, I didn’t list all the many options you can eat on a low FODMAP diet–adjust to your liking!} But, a balanced plate provides a nice variety of nutrients while keeping the belly calm and satisfied.

For easy tips on creating a balanced low FODMAP meal, use one of my favorite handouts!  Click here for PDF.How-to-make-a-low-FODMAP-meal-final-pdf

As with most things in life, it’s all about balance.


24 replies on “Portion Size Matters on the Low FODMAP Diet

  • Corky Parker

    hi Kate
    love your blog and site. forgive me if I have just overlooked it but do you have info on turnaround time for problems? in other words — if you’re going to have issues with some foods is there a rough time period that they’ll shop up in? if it’s been 24 hours with no problem are you in the clear? or is it still a cumulative thing? thanks much. corky. ps. come down to the Finca for a fodmap retreat!

    • katescarlata

      Hello Corky…Um…YES…I have been talking about doing a low FODMAP retreat for some time!! How fun would that be?!!
      Let’s talk more about this concept! email me at kate@katescarlata.com. I would love a safe travel destination for my fellow FODMAPers. And now to your question, if you are symptom free for 24 hours–you are likely in the clear…especially if your IBS symptoms are more diarrhea oriented. Sometimes though–foods have a longer cumulative effect (especially in more constipated folks)–I am not sure its FODMAP related–but perhaps something else in the food. For example, low lactose dairy products can be an issue in some–particularly constipated patients. So day #1 might be okay–but by day #3 with cheese in their diet–they may experience constipation. This may be due to opiate like chemicals in the milk…though not sure.

  • Hagit D

    Thank you very much for the information. You are very reassuring and have excellent tips!!
    You addressed some of my personal questions. Waiting for your next post…

      • Hagit D

        Hi again,
        I found in my local organic store a brand of spelt oats. It looks exactly like regular oats only made of spelt. I tried once to make a porridge from the oats and rice milk but I think the effect on my stomach was not so nice…
        Want to try it again because its a great breakfast on the way to work but I’m a little scared…

      • katescarlata

        Spelts are variable–and my guess would be that spelt oats might be high FODMAP. I would avoid while on the elimination phase of the low FODMAP diet. Perhaps try your tolerance to spelts first–with a sourdough spelt bread. The sourdough culture helps reduce the FODMAPs in spelt by fermentation. Perhaps try quinoa flakes and small amount (1/4cup) regular oats.

  • Peg

    This is very helpful, Kate! Thank you! I’ve been wondering about how much portion size effects my success on the low FODMAP diet. For instance, I realize now that I’m eating too much oatmeal in the morning. Need to cut down and test at the 1/4 cup dry oats amount and then move up later from there. It’s good to hear that I can eat smaller portions of different foods but can have them more than once throughout the day.

  • Kim M

    Need help in getting a diagnosis for my daughter. I don’t know if she has SIBO or CSID or IBS, but she has low sucrose and glucoamylase enzymes. Can’t seem to find a pediatric GI doc to get a second opinion and recommend treatment. She also has chronic constipation. Any suggestions would be appreciated!

  • Contented Belly

    This post is a good reminder to not only be careful of what you eat, but also how much. Something I struggle with. What are your thoughts on almond milk? The recommendation is 10 almonds and I know different people can tolerate different amounts but is the milk too many almonds on the low fodmap diet?

    • katescarlata

      Not sure about almond milk. Likely it will be high FODMAP—but might vary brand to brand. Almonds contain water-soluble fructans and GOS which likely leach into the milk when it is made. Will have a better idea when different brands are officially tested.

      • katescarlata

        Rice milk, lactose free cow’s milk–I like Organic Valley brand, personally. Coconut milk can work too. Just read ingredients as brands do vary. Trader’s Joe’s light canned coconut milk is a nice option. You can add water to thin it out. I buy it and freeze it in an ice cube tray–then add a cube to my morning oats, Jasmine rice, or Thai dishes. You can also blend with a frozen banana into a dessert. YUM!

  • Karen

    Hi Kate,

    I was delighted when two friends told me their doctors told them about the FODMAP diet. In both cases, they were just told to avoid all the FODMAP foods! I was disappointed in hearing this. When I told them more about the diet, they both said that their doctors probably knew best. Are you hearing of lots of cases like this? Thanks!

  • Jennifer

    Thanks a bunch for this post!! I think the thing that still confuses me a bit regarding the monash app and portion sizes is whether a larger portion of a green light food is allowed if it doesn’t have a disclaimer. For instance, blueberries are a green light food, but it is specifically stated that larger servings (> 40g) may not be tolerated. Strawberries also have a green light, but it does not say anything like servings >10 strawberries may not be tolerated. If not stated, would the food be considered tolerable for most people despite portion?

    I always ate a ton of veggies at each meal. It seems a little difficult, and not optimal, to only eat 1/2 cup eggplant, 2 Brussel sprouts, or 1/2 cup zucchini only. Can we really get all our phytonutrients, micronutrients, and antioxidants this way? Thanks for the help!!:)

  • Sari Lynn Kessler

    How can I get the info concerning FODMAPs if I don’t have access to the APP? Wonder if you can give me an alternative way to obtain the information.

  • april

    Hello! I have a question for you- I know hard cheeses are low fodmap, but what about reduced-fat hard cheeses like reduced-fat cheddar or 2% Monterey jack? Thank you!


  • Jennifer

    Many thanks, Kate, for your reply re. fodmaps in minimal-carbohydrate pea-protein isolate – cautiously, I think I shall give this a go!
    With apologies for being so very tiresome – I’ve another, fairly silly & random, question: lately I’ve been trying to find some information on mulberries, without much luck – although they seem to be OK, as to fructose/ glucose ratio, do you happen to know how they they fare, when analysed for Polyols & Fructans? All very best wishes, Jennifer.

  • kristin

    Hi, Kate!

    I’ve been following the 21-day Tummy Diet book, and I’m heading back into phase 2, and adding in the exercises. I was off exercise for a while because of a back injury, but I’ve been cleared to start! My question is this: I am feeding a family, and my husband and kids don’t love all the bell peppers, scallions and chives that are suggested in the recipes (he, specifically, never has liked onion, garlic or peppers, even before this adventure). Do you have a suggestion for alternatives?

    • katescarlata

      HI Kristin, I hope you find the 21 Day Tummy book helpful. It has so much great info and the diet plan is healthy! Just delete chives or garlic infused oil! Sub in straight olive oil–perhaps. A good sub for bell peppers can be zucchini or summer squash–but obviously–they might not work for some of the recipes. You might try mixing and matching some of the recipes that sound more suitable for your family’s taste.

Comments are closed.