Problems with protein powder digestion can often put us off supplementing with protein powder.  One of the factors to consider when adding protein powder supplementation to your diet should be the digestibility of the protein you choose. Whey protein is considered the best source of protein as a supplement, but many people experience gas, bloating or constipation when using it. For people with lactose intolerance, whey may trigger unwelcome reactions. Having a better understanding of how you take protein powder and potential side effects and reactions is as important as understanding your options in choosing milk-based or non-milk-based protein products.

Lactose intolerance from milk based protein powders

Whey protein is made from milk and unless you are spending more to purchase hydrolyzed whey protein (a good investment some say), it will contain lactose related compounds. If you are lactose allergic or intolerant, this can cause several problems including an allergic reaction, gas, bloating and constipation. If you do not want to switch to another type of protein and are still experiencing those symptoms – you should first try a whey isolate and if you still experience discomfort, try the hydrolyzed whey compounds. These still provide all the power of the whey protein but they have been processed to remove the lactose related compounds from the powder.

What about non-milk based protein powder?

Another option is to choose one of the non-milk based protein powders. Soy protein is the most common option, but soy is a fast digesting protein which may not be the optimal choice. If you are transitioning from casein powder (taken before bed for muscle recovery), you’ll find soy will be digested quickly much more quickly and may cause weight gain if taken late at night. You may find turning to the newer pea, rice or seed proteins (hemp or flaxseed) a better choice. These options provide a high percentage of protein per serving but are slow digesting to give your body a more stable fuel source.

Is rapid consumption of protein powder a cause of gas?

If you aren’t lactose intolerant and you are experiencing gas, bloating or constipation problems, the issue may stem from drinking the protein powder too fast and not staying properly hydrated. Since basic whey protein can have a high percentage of fat, if you aren’t staying properly hydrated and eating a balanced diet, that fat can cause problems with your digestive system. Learning to drink slowly is key. It reduces the amount of air introduced to the digestive track. Many people don’t consider the speed of consumption as they are gulping down shakes after a workout. It is better to have some water first, let your breathing settle and then drink your shake at a good calm pace for improved protein powder digestion.

The role of fibre in protein powder digestion

Because of the higher fat content in whey, fibre has an even more important role than with non-milk protein powders. Fibre is necessary to allow the body to absorb nutrients required and to collect excess nutrients to be passed from the body. If you aren’t getting enough fibre in your diet you will be bloated, experience gas and also be constipated. It’s a good idea to add a serving of a fibre supplement to at least one of your protein drinks during the day to improve protein powder digestion.


Genton, Laurence; Melzer, Katarina; Pichard, Claude (2010). “Energy and macronutrient requirements for physical fitness in exercising subjects”. Clinical Nutrition 29 (4): 413-423.

Ten Have, Gabriella A.M.; Engelen, Marielle P.K.J.; Luiking, Yvette C.; Deutz, Nicolaas E.P. (2007). “Absorption Kinetics of Amino Acids, Peptides, and Intact Proteins”. International Journal of Sport Nutrition and Exercise Metabolism 17: S23-S36.

Last reviewed 06-Nov-2016