Just when you thought you had this FODMAP thing covered – you’ve downloaded the Monash app, you’ve emptied your cupboards and started the elimination phase and you’ve even got a few low-FODMAP meals under your belt (literally) -  you see a post about stacking and you wonder ‘what’s this new thing I have to worry about?’.

In this blog we explain the term stacking. Why it’s likely not a problem for you, but if it is, how you can avoid it.

Like many things in life, success with the FODMAP diet can be all about timing and enjoying things in moderation.

FODMAPs

The low FODMAP diet has three stages

How much is too much?

Traffic Light System

Some examples

What is stacking?

Stacking occurs when one or more of the different types of FODMAP in the constituent foods in the same meal (or in meals consumed close together) add up to more than the green cut-off point for that FODMAP.

Or together all the different FODMAPs add up to more than the green cut-off point of 0.5g for total FODMAPs.

Our recipes avoid stacking

We have been extra careful when preparing all the recipes on our site. For example, if we have two ingredients in a recipe that have a low-FODMAP serving size, we have only included around half the maximum green serving size the two ingredients, to ensure that together they don’t tip the scales.

If you think that stacking is causing problems for you, you may wish to take a similar approach. We give you some more tips below.

Six tips to avoid stacking

1.      Take the approach mentioned above and make good use of the Monash app. If you have two or more foods in the same meal with the same fodmap, reduce the maximum ‘green’ serving size of each down a little.

2.      Dilute the FODMAPS. Try to include a good amount of the ‘green’ low-FODMAP foods in each meal – e.g., meat, poultry, fish, eggs, rice, oranges and carrots.

3.      Be like Goldilocks and go for the middle-sized bowl. Stick to small to moderate portion sizes and eat regularly. If you wait a very long time between meals, you are more likely to be very hungry and consume larger servings and hence, more FODMAPs.

4.      But do spread out your meals and snacks by 3 to 4 hours. It takes around 2 to 4 hours for the stomach to empty food into the small intestine (although it can be as quick as 40 minutes for a liquid meal). You want gaps between when the food containing FODMAPs reaches the large intestine and fermentation happens. If you let the stomach empty completely before eating, then you will also have a gap between when the different meals reach your large intestine.

5.       If you can’t wait that long between meals and a snack - then stick with those foods in which there are extremely low or undetectable amounts of FODMAPs for your snacks. They can be identified in the Monash app as those foods with a single green dot next to them in their listing and wording such as ‘FODMAPs were not detected in this food’ or ‘Only trace amounts of FODMAPs were detected in this food’ in the app. Good examples are carrots, rice, oranges, and mandarins. Something like an orange and a glass of lactose free milk would work, or carrot sticks and a herb dip made with lactose-free yoghurt. Include more of the foods with some FODMAPs in your main meals (at green serving sizes) to ensure you are getting as much variety in your diet as possible.

Remember it will get easier if you make it through to the personalisation phase and have more food options. And ultimately - food freedom with minimal restrictions is the goal!

6.      Fruits tend to be high in FODMAPs and can contain multiple FODMAPs. Try to have only one serve of fruit at a sitting and stick to the recommended 2 serves per day. Watch out for fruit combos in a fruit salad or smoothie.  Combine fruits with different FODMAPs like strawberries (contain fructose) and raspberries (contain fructan) and a blackberry (contains sorbitol). Alternatively, combine mango (contains fructose) with kiwi fruit (contains fructan) and a clementine (fodmaps undetected). And keep to a single serving size of 1 cup of fruit overall at each sitting.

More on timing and motility

Our guts all have a natural cycle of activity. There are cycles of quiet periods where the contents are gently moved backwards and forwards for mixing and then periods of more propulsive activity that propels the contents forwards along the length of the gut. This is known as the Migratory Motor Complex and tends to occur every couple of hours between meals. For some it coincides with a loud rumbling tummy and hunger. It acts as a housekeeping system that keeps everything moving through your digestive system. The duration of your natural cycle will be linked to whether you have long or short transit times through your gut. A short cycle will contribute to a short transit time, and vice versa.

IBS symptoms are largely connected to fermentation in the large intestine and hence typically occur 4 to 24 hours after eating a food rich in FODMAPs. If you have slower motility, it will take longer for the food to reach the large intestine and symptoms will occur later than in someone with faster motility.

Typically, those with IBS-D have faster motility and those with IBS-C have slower motility. This knowledge may help you to work backwards and identify a trigger food for you. However, we would always recommend working with a dietitian to systematically reintroduce foods and keep a dairy of symptoms.

Riding the waves

Food entering your stomach and then moving into the small intestine triggers much larger propulsive waves in the large intestine, which result in a strong urge ‘to go’, perhaps as soon as 15 minutes after eating. This is known as the gastrocolic reflex. This is enhanced when the food contains fats or oils. These strong propulsive waves in the colon also occur in the short period after waking.

If you have IBS, you may be able to use these natural patterns to your advantage. If you have IBS-C, ensuring breakfast is a good size and contains some healthy fats (full-dairy milk or some olive oil), may help with your morning movements.

Similarly, those with IBS-D may wish to eat small meals, reduce fat and oil content when eating out, and leave more time in the morning before leaving home to accommodate toilet visits.

These are things that you have probably worked out for yourself, but sometimes it is reassuring to know the science behind it.

Join in

Written by: Dr Mary Webberley, Chief Scientific Officer at Noisy Guts. Mary has a background in biology, with two degrees from the University of Cambridge and post-doctoral research experience. She spent several years undertaking research into the diagnosis of IBS and IBD. She was the winner of the 2018 CSIRO Breakout Female Scientist Award.