A protein shake is meant to leave you feeling nourished, not bloated, uncomfortable or making an urgent dash to the bathroom.
However, bloating, diarrhoea, cramping and an IBS response are reasonably common complaints after drinking protein powder. This does not necessarily mean protein powders are off the menu for you. It may simply be the type of protein, the serving size, another ingredient in the formula or what you are mixing with it.
If you are specifically looking for a non bloating plant protein powder in Australia, it helps to understand what may be behind your symptoms. Your gut is highly individual, so a little trial and observation can make a big difference.
Why Can Protein Powder Cause Bloating or Diarrhoea?
There is no single protein powder that will suit every digestive system. Common triggers can include:
- Lactose or dairy in whey protein
- Certain plant protein sources
- Sweeteners and flavouring ingredients
- Prebiotic fibres
- Suddenly increasing your fibre intake
- Drinking too much in one sitting
- Ingredients added to your smoothie
- The type of milk used to mix your shake
For people with IBS or a sensitive digestive system, even a small amount of a particular ingredient may be enough to trigger bloating, gas or changes in bowel habits.
If you have had trouble with protein powder in the past, it is worth taking a closer look at the ingredients list. Monash University’s guidance on protein powders and IBS recommends checking for lactose and polyol sweeteners such as sorbitol, mannitol and xylitol, as these may trigger digestive symptoms in sensitive people. Some plant protein powders may also retain small amounts of naturally occurring FODMAPs during processing, which can be problematic for certain people with IBS.
Start Low and Go Slow
If you are trying a new protein powder, do not assume you need to begin with a full serve.
Start with half a serve, or even less if you have a particularly sensitive gut, and see how your body responds. Ideally, test it at home rather than in the office or just before an important meeting. Your digestive system does not always respect your calendar.
You can then gradually increase the amount over several days. This can help you distinguish between a genuine intolerance and temporary discomfort caused by suddenly introducing a concentrated new food. It may also give your digestive system time to adjust to ingredients such as plant protein or prebiotic fibre.
If a small serve still produces significant symptoms, stop taking it rather than trying to push through.
Consider the Type of Protein
Whey protein works well for many people, but it may not suit those who have difficulty digesting lactose or dairy. Whey protein concentrate generally contains more lactose than whey isolate, although tolerance varies considerably.
Plant protein is naturally dairy free, making it a useful alternative. However, plant based does not automatically mean symptom free. Some people find pea, soy or other plant proteins harder to tolerate. It is highly individualised as to how one’s gut may respond to plant vs whey protein.
Bold Health Protein Boost combines pea and brown rice proteins to provide all nine essential amino acids. It is also dairy free, lactose free and gluten free, removing several common dietary triggers. Individual responses can still vary, particularly for people with diagnosed IBS.
Look Beyond the Protein
Sometimes the protein itself is not the problem.
Check the ingredients list for polyol sweeteners, also known as sugar alcohols, such as sorbitol, mannitol, xylitol or maltitol. These may trigger bloating, gas or diarrhoea in people who are sensitive to them.
Prebiotic fibre can support a healthy gut, but it can also cause temporary gas or bloating in some people, especially when introduced too quickly. If you already have IBS, check the full ingredient panel rather than relying only on claims such as natural, clean or plant based.
Keeping a simple record of the product, serving size and symptoms can help you identify patterns.
Check What Is Going Into Your Smoothie
A protein shake can quickly become a very large meal.
Adding fruit, vegetables, seeds, nut butter, oats and fibre supplements can be a healthy choice, both individually and together. However, introducing them all at once can create a sudden increase in fibre and volume that your gut may not be ready for.
Too much liquid or food arriving in the gut at once may contribute to discomfort. In some people, a concentrated load of poorly absorbed ingredients can draw water into the bowel. This can result in loose stools, diarrhoea and a very urgent trip to the toilet.
For others, rapidly increasing fibre without drinking enough fluid may cause constipation.
Start with a simple shake. Try protein powder with water or your usual milk, then introduce additional ingredients one at a time.
Experiment With Your Mixing Liquid
Your choice of liquid matters too.
If you use dairy milk, consider whether you normally tolerate it. Full cream and reduced fat milk contain similar amounts of lactose, so changing the fat content may not solve a lactose related problem.
If you suspect your usual milk is contributing to your symptoms, try mixing the protein powder with water first. This is the simplest test because it removes most other variables.
You could then trial lactose free milk or a plant based milk you already know you tolerate well, such as unsweetened almond, soy or oat milk.
Check the label for added sweeteners, fibres, gums and thickeners, as these may affect sensitive digestive systems.
Whichever option you choose, keep the rest of your shake simple. This makes it much easier to determine whether the milk, protein powder or smoothie additions are causing the reaction.
Protein and Digestion After 50
Protein becomes increasingly important as we age, particularly for maintaining muscle, strength, recovery and independence. At the same time, the body can become less responsive to dietary protein. This change is known as anabolic resistance.
Bold Health was created specifically with healthy ageing in mind. Its nutrition scientist formulated Protein Boost provides 21 grams of complete plant protein per full serve. It also contains digestive enzymes to assist with breaking down protein and prebiotic fibres to support gut health.
The formula is Australian owned, third party batch tested and designed specifically for adults over 50. You can learn more about the science and ingredients behind Bold Health.
Finding What Works for Your Gut
The best protein powder is not simply the one with the highest amount of protein. It is one you can tolerate, enjoy and use consistently.
Begin with a small serve, keep the shake simple and change only one ingredient at a time. This gives you a much clearer idea of what your digestive system can comfortably manage.
If bloating, diarrhoea, pain or bowel changes continue, speak with your GP or an accredited practising dietitian. This is particularly important if you have IBS, unexplained weight loss, blood in your stool or persistent digestive symptoms.
Your gut should not have to suffer for you to get more protein.
Frequently Asked Questions
1. Why does protein powder make me feel bloated?
Protein powder may cause bloating because of the protein source, lactose, sweeteners, added fibres or the amount consumed. Your mixing liquid and other smoothie ingredients may also contribute.
2. Is plant protein easier to digest than whey protein?
Plant protein can be easier for people who do not tolerate dairy or lactose. However, some people find certain plant proteins or added fibres difficult to digest, so individual responses vary.
3. Can protein powder cause diarrhoea?
Yes. A large serve, lactose, certain sweeteners, added fibre or drinking a shake too quickly may cause diarrhoea in some people. Starting with half a serve may help you assess your tolerance.
4. What should I mix protein powder with if I have a sensitive stomach?
Start by mixing it with water or a milk you already tolerate well. Lactose free milk or unsweetened almond milk may suit some people. Keep the shake simple and introduce other ingredients gradually.
5. Is Bold Health Protein Boost suitable for people with IBS?
Bold Health Protein Boost is dairy free, lactose free and gluten free. However, it contains plant proteins and prebiotic fibres, which may affect people with IBS differently. Start with a small serve and speak with a dietitian if symptoms continue.
