Dairy Intolerance: What Gives?

Dairy Intolerance: What Gives?

If you find that your body reacts differently to foods in the dairy category, we are about to shed light on why.
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I'm going to get real honest with you about my dairy issues. Milk gives me gas. Whey protein brings on the brain fog. I seem to digest cottage cheese and Greek yogurt just fine (thank goodness because they're daily diet staples)! 

What gives? These are all dairy-based protein sources, yet my body responds so differently to each one.

If you find that your body reacts differently to foods in the dairy category, we are about to shed light on why. Once you uncover the why, you may be able to expand your dairy-based protein choices successfully.

First, let's break down what's in milk, and then we'll dig into what might be going on internally when you take in dairy products.

  • Lactose: The sugar found in milk
  • Whey: 20% of the proteins found in milk
  • Casein: 80% of the proteins found in milk


Lactose is the sugar found in milk. If your body doesn't make enough lactase (the enzyme to break it down in the small intestine), the lactose passes into the large intestine. This creates dairy-intolerance symptoms like gas, bloating, and diarrhea. 

Sometimes, people who can't tolerate dairy milk can enjoy Greek yogurt instead without the same symptoms. That's because Greek yogurt is processed differently than cow's milk. Its straining process removes most of the whey and lactose, leaving a mostly casein-based protein source. Many Greek yogurts also have added probiotics to enhance digestion. Options aren’t necessarily limited to only Greek yogurt. 

Some people with minor lactose intolerance can also have some cheeses. Many aged cheeses, like cheddar, are lower in lactose. Cottage cheese tends to be another favorite among fitness enthusiasts due to its high protein content and grab n' go packaging. Cottage cheese does have lactose, as well as whey and casein. However, some brands add probiotics or other enzymes that enhance lactose digestion. 

If you’re looking for digestion-friendly non-refrigerated options, take a close look at your protein powder’s nutrition label. Some, like WRKETHIC, include prebiotics, probiotics, or digestive enzyme complexes that may work for you. 

Dairy-based food sources with lower lactose: 

  • Greek yogurt
  • Muenster cheese
  • Cheddar cheese
  • Provolone cheese
  • Parmesan cheese
  • Swiss cheese
  • Cottage cheese with added probiotics or enzymes 
  • Protein powders with added prebiotics, probiotics, or digestive enzymes


Whey comprises approximately 20% of the protein found in milk. Many physique enthusiasts enjoy whey protein post-workout due to its high BCAA (branched-chain amino acid) content and quick digestibility.

While whey does contain lactose, its processing leads to a lower lactose content than milk. All whey is not created equally, however. Whey concentrate contains approximately 70-80% protein and is higher in lactose, carbohydrates, and fat, than its whey isolate counterpart. 

Whey isolate contains approximately 90% protein and is lower in lactose, carbohydrates, and fat than its casein counterpart. Since whey isolate is lower in lactose, it tends to digest easier. An example of a great whey isolate is EVOchem Nutrition’s Hydro-Pro. If lactose is a concern, be sure to check your supplement label to see whether you are consuming a concentrate or an isolate. 


Casein is also a milk-derived product, accounting for 80% of the protein found in milk. The body digests casein slower than whey, making it ideal for between-meal and before-bed consumption. Casein is found in its naturally occurring form in creamy dairy sources that are higher in protein. Examples include cheese, cream, half and half, kefir, and pudding. Casein is also a popular protein-shake supplement. Since it is thicker than whey, many physique athletes use it to make puddings and other desert-like protein treats. EVOchem’s Casein is a great example; it comes in vanilla, chocolate coconut, and cinnamon apple! Yum! 

With casein digesting at a slower rate than whey, you may feel completely different in terms of satiation, energy, or ease of digestion when consuming one versus the other. 

SUMMARY: Assuming you don't have an actual dairy allergy, dairy-based proteins may allow you to expand your food choices to support your physique and training goals. Beyond high protein content, dairy offers a valuable source of calcium, vitamin D, potassium, and magnesium to support your overall health. If you are experiencing feelings that affect your sense of well-being after consuming dairy-based proteins, use the above tips to begin honing in on which elements of dairy are favorable versus unfavorable to support your overall fitness and wellness.  


ABOUT THE AUTHOR: Dr. Meredith Butulis, creator of the ISSA Fitness Comeback Coach Certification (online), is a Sports Medicine Physical Therapist, NSCA Certified Strength and Conditioning Coach, ACSM Certified Exercise Physiologist, NASM Certified Personal Trainer, and Precision Nutrition Certified Nutrition Coach in practice since 2002. She consistently walks the talk as a fitness, physique, and OCR world-level competitor and lifestyle transformer since 2006, celebrating many wins along the way. Want more total fitness lifestyle inspiration and interaction? Follow Dr. Meredith on Instagram @Dr.MeredithButulis, YouTube on the “Fitness Comeback” Channel, or join the free “Fitness Focus Fuel” Facebook Group