Protein shakes are quick and convenient, but they can cause an unpleasant side effect -- gas. By experimenting with different ingredients and changing the way you consume them, you might be able to determine -- and eliminate -- the cause of the trouble. Talk to your doctor if your digestive issues don't go away.
Check Your Protein Source
Persistent gas after drinking a protein shake might signal that you have an allergy or sensitivity to the source of protein you're using. Common culprits include whey protein or casein protein powder. Precision Nutrition coach and researcher John Berardi, Ph.D., suggests switching to another brand of protein powder because different brands vary widely in the exact makeup of their product. If that doesn't help, try switching to a different type of protein source. Brown rice, pea, hemp or soy protein are all options.
Go Easy on the Fiber
Suddenly increasing your intake of fiber can cause gas. If you've recently switched to a high-fiber protein powder or are including lots of dark leafy greens, fruits, nuts or seeds in your shake mixture, fiber might be behind the problem. Ease into fiber-rich shakes by gradually increasing the amount you drink over the course of several days. Registered dietitian Tanya Zuckerbrot suggests starting with one-fourth of a serving the first day and adding one-fourth more each successive day if you don't experience gas.
Look Out for Sugar Alcohols
Some protein powders contain sugar alcohols, low-calorie substances used to sweeten products without sugar. Mannitol, maltitol, isomalt, lactitol, xylitol, sorbitol, glycerol, erythritol and hydrogenated starch hydrolysates are all examples of sugar alcohols. In some people, they can cause a number of digestive problems, including gas. Look for an unsweetened protein powder that does not include sugar alcohols, or experiment with shake recipes that use naturally high-protein, unsweetened ingredients like tofu or nonfat yogurt.
Inspect the Dairy
If a protein shake containing milk, cottage cheese or yogurt typically causes you to develop gas, you may be lactose-intolerant. Try using an alternative to cow's milk such as products made from almond, soy or hemp milk or ones derived from animals other than cows, like sheep or goats. You can also look for lactose-reduced milk or take a nonprescription lactase enzyme supplement if you don't want to give up regular dairy products.
Slow It Down
Your protein shake may cause gas simply because you're drinking it too quickly. According to Zuckerbrot, the faster you drink a beverage, the more air you'll swallow. All that extra air in your digestive system can lead to gas. The problem is exacerbated if you blend lots of air into your shake to make it frothy. Blend your shake less and drink it slowly to reduce the amount of air you swallow.