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Does protein affect IBS?
This is question popped up with a client a few days ago so I thought it was worth putting some information out there as protein intake for IBS sufferers isn’t often discussed.
We tend to associate fermentable carbohydrates (AKA FODMAPs) with IBS symptoms as they can draw water into the small intestine (contributing to diarrhoea) and are fermented by the good bacteria living in your large intestine (causing bloating and gas), and up to 80% of people with IBS will find some relief by reducing their intake of FODMAPs.
High fat and fried foods can also trigger cramping, diarrhoea and urgency in some people too, although this is a very individualised response and there is no known mechanism for this.
But does protein affect IBS? The answer is: yes, it can!
Protein can slow down gut transit time, so if you have diarrhoea-predominant IBS, making sure you’re getting sufficient protein can help to firm up your stools. And if you have constipation-predominant IBS, it may be wise to make sure you’re not eating too much.
How much protein do I need?
Most healthy adults require between 0.75 and 0.8 grams of protein per kilogram of lean body weight for good health. Lean body weight is your non-fat mass (bones, organs and muscles etc.). As this is difficult to ascertain without very specialist equipment (those scales in the gym aren’t very accurate – sorry!), most people can just calculate this using total body weight.
For a 65kg person, this would be around 52g of protein a day, and for an 80kg person, this would be around 64g of protein a day.
However, as we don’t tend to eat the same things every day (and IDK about you but I have much better things to do with my time than worry about counting macros!), think of ideal protein intake as a range.
Your body is smart and recycles amino acids – the building blocks of protein – to use where the need is greatest, so you don’t need to eat an exact amount of protein every day.
Getting between 10 to 15% of your calories per day from protein is the range I typically recommend to clients, depending on their activity level.
So for our hypothetical 65kg person, this is 50 to 75g a day, and for our 80kg person, this is 63 to 94g a day.
This is probably less than you thought, right?
There’s really no need to go over the top of this range unless you’re an athlete doing 8 or more hours a week of vigorous exercise (by this, I mean intense enough that you can’t hold a conversation). The majority of us recreational exercisers don’t fall into this category.
If you’re over 40 years old, shooting for closer to the top end of the range is advisable to prevent age-related muscle loss (sarcopenia).
There are other factors that may affect how much protein you need, like whether you’re pregnant, trying to build muscle, or want to lose weight, but that’s a whole other blog post.
The reality is, most people eat more protein than they really need (with one caveat below).
And having IBS doesn’t increase your protein requirements.
Protein and IBS – what else matters?
This is no different than advice for the general population (i.e. those who don’t have IBS), but spacing your protein intake out throughout the day is recommended. As a general rule, anything greater than 20-25g of protein eaten in one meal is unlikely to be synthesised, and will be converted to be stored as fat or flushed down the toilet.
Eating too much protein in one meal could block you up, so try to make sure your breakfast, lunch, dinner, and snacks all have an even amount of protein in them.
For our 65kg person eating 15% of their calories from protein (75g), this could be 19g per meal and 6g per snack.
For our 80kg person eating 15% of their calories from protein (94g), this could be 23g per meal and 12g per snack.
This breakdown is based on eating 3 meals and 2 snacks a day.
Protein on a plant-based diet
If you eat a balanced plant-based diet with a good variety of legumes, whole grains, nuts, seeds, and fruits and veggies, and your calorie intake is sufficient, you’re probably getting enough protein into your diet.
However, if you’ve gone plant-based and just removed animal products from your meals without consciously replacing them with a plant source of protein like tofu, tempeh, beans or lentils, then you might not be eating enough protein.
Another factor to be aware of is the Low FODMAP Diet. Many plant-based sources of protein are high FODMAP, so it’s really not advisable to tackle the Low FODMAP Diet without the support and guidance of a FODMAP-trained IBS specialist. We can help make sure your elimination phase diet is balanced, and that you don’t get stuck with an overly restrictive diet for longer than absolutely necessary. Need help? This is my jam! Drop me an email and let’s chat.
Low FODMAP sources of plant-based protein
The elimination phase of the low FODMAP diet can be tough for plant-based eaters as most legumes are off the menu. It’s not impossible to meet your protein requirements though! While the myth that plant-based eaters need to combine proteins has long since been busted, I recommend being conscious of both primary and secondary protein sources and aiming to eat a variety of foods from both of the below lists:
Primary protein sources
- Firm tofu
- Edamame beans
- Vegetarian mince (mycoprotein)
- Nuts and seeds (except cashews and pistachios)
- Canned lentils and some canned beans – although ‘safe’ serving sizes are small
Secondary protein sources
- Grains like rice, oats, and millet
- Gluten-free pasta
- Spelt sourdough, wheat bread, and gluten-free bread
- Leafy greens like kale, spinach and collard greens
- Broccoli heads
Paying attention to portion sizes is key to ensuring your FODMAP intake is low enough for IBS symptom relief – please use the Monash app to check.
What about protein powders?
High protein products are all the rage these days, fuelled by our societal obsession with this macronutrient and some clever marketing that wants us to believe we’re all suddenly going to waste away if we don’t supplement our diets.
If you’re really struggling to get the protein you need (based on the calculations I’ve provided above), then maybe you’ll want to try out a protein powder.
Just be aware that this type of protein can have affect IBS symptoms. Protein powders and bars often contain high FODMAP ingredients like artificial sweeteners and inulin and also give you a large hit of protein in one go, which can all lead to pain, bloating, gas and constipation.
Some low FODMAP certified protein powders are:
Taking a food-first approach is what I advocate, so try to meet your protein requirements with food before you reach for a protein-packed supplement.