It is not a subject everyone likes to discuss, but, if you are on meal replacements or have been boning up on your protein to lose weight, you have experienced them.


There can be a number of reasons why we experience gas, bloating, abdominal distention, diarrhea, or even constipation when starting a high protein diet, meal replacement plan, or increase our protein supplementation.


Protein is harder for our bodies to digest and metabolize. It takes longer to breakdown.


The average “regular” American diet gets only 15% of total calories from protein.


Most meal replacements amp the protein percentage to 25% or more! So, it is easy to see why your body may need time to adjust.


The by-product of protein metabolism also contributes. Once our bodies have digested and metabolized protein, we are left with nitrogen in our guts.


Fiber can also be a factor in how your GI system responds to increased protein supplementation.

Fiber is found in carbohydrates and this is a nutrient we typically limit when eating high protein or on meal replacements. The decreased carbohydrate consumption leads to less fiber which, in turn, leads to gastrointestinal changes.


Using a fiber supplement can help.


Lactose is another offending factor. Some of us are more lactose intolerant than others but just a mild intolerance can lead to gas, bloating, and diarrhea. Looking for a more isolate lactose supplement can prevent much of the abdominal discomfort. Concentrates have more lactose. Always ask.


Taking a probiotic can help with lactose intolerance. I use Align probiotics daily.

You can also use Lactaid or Digestive Advantage Lactose Defense Formula supplements.

You can also sprinkle a little cinnamon, ginger, or peppermint into your protein shake to cut the gas and bloating. Garlic, cumin, and dill in your protein soups can help.


Watch the sugar alcohols: sorbitol, mannitol, xylitol, maltitol, lactilol to name a few…

They are carbohydrates but our bodies cannot absorb or metabolize them easily. Some are more sensitive to sugar alcohols than others. If “sugar-free” candy, sweeteners, or artificial flavorings upset your tummy, you may have a sensitivity to sugar alcohols.


Cut back on the froth. Anytime we blend a protein shake, we create air bubbles. Letting those bubbles settle before drinking can eliminate the air you swallow (which turns to gas). And, never use a straw!


Gluten is another ingredient that may be aggravating your gut. You do not need to have Celiac Disease to have a gluten sensitivity. Look for protein supplements and meal replacements that do not contain gluten.


The type of protein supplement is also another important issue to consider. Whey and casein are both by products of milk but whey is the safer of the two. Casein is more likely to cause GI side effects.


Any time we introduce a new food or more of a particular nutrient, it can have implications on our body’s GI function. Know your facts and choose wisely.


OPTIFAST® meal replacement nutritional products are made from a whey and soy based isolate (less GI problems). They do contain some lactose but Nestle Health Science has worked on formulating a product that has less than most.

They are gluten-free and contain 100% of the vitamins and minerals you need daily.


If you have extreme diarrhea, you may need to seek the advise of whoever is medically monitoring your weight loss.

If you have constipation, this is often a hydration issue. Increase your water consumption first, then talk to your medical advisor.


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