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Protein farts

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What Are ‘Protein Farts’ and How Can You Stop Them?

Noticing more frequent, and, well, aromatic farts as you consume more protein? Nope, it’s not just you. Find out why—and how to calm things down.

By Karla WalshFebruary 26, 2024


If you’re looking to get stronger, you may have upped your protein consumption, as the muscle-building macronutrient is an MVP when it comes to hitting fitness goals. 

Eating foods with amino acids—the building blocks that make up protein—can help the body repair muscle proteins that have been broken down during exercise and create new ones through muscle protein synthesis. So it stands to reason that those who have a goal of building muscle crank up their protein intake both before and after a workout.

Unfortunately, amping up your protein consumption can also do a number on your gas game, even when you’re within the recommended range of healthy macronutrient consumption. Yes, we’re talking about protein farts. Here’s what you need to know.

What Are Protein Farts?

"Protein farts" is a term that refers to increased flatulence or smellier gas that some people experience while consuming a diet higher in protein, explains Danielle Crumble Smith, RD, a registered dietitian in Flintstone, Georgia, and a spokesperson for Top Nutrition Coaching.

“Despite chatter around protein farts when people increase protein intake, scientific research to support this phenomenon is weak,” says Kelly Jones, RD, a Newton, Pennsylvania-based board-certified sports dietitian. 

That being said, excessive protein intake in one sitting (especially of certain types of protein, such as protein powder) may affect how the bacteria in the lower digestive tract interact with amino acids, creating more foul-smelling byproducts, Jones adds. 

What Really Causes Protein Farts?

A variety of things could be causing these so-called protein farts. That’s why Desiree Nielsen, RD, a Vancouver, Canada-based registered dietitian and the author of Plant Magic, puts on her detective cap when someone comes to her complaining about them.

“We need to do some sleuthing to determine if their protein choices may be contributing to digestive ills or if it is something about their dietary pattern as a whole,” Nielsen says.

It might be tempting to blame the often misaligned beans if they’re part of your new high-protein diet, but there’s no need to villainize those chickpeas, lentils, and limas. 

“Despite the associations between beans and flatulence, those who consume beans regularly have gut bacteria that adapt to the regular intake of more fiber and prebiotics, which can actually offer gut health benefits,” Jones says. “After several weeks of regular legume consumption and bacteria adaptation, flatulence should subside.” 

The real potential causes of protein farts include:

1. Protein Intake “Crowding Out” Fiber-Rich Foods 

Eating a high-protein diet is often at the expense of higher-fiber choices, which can hamper digestion or even cause constipation and an increase in gas, Nielsen says. More time between bowel movements means more time for waste products to interact with bacteria and ferment in the digestive tract, potentially lending to increased flatulence—and smelly protein farts.

2. Gut Bacteria Fermentation Byproducts

If the protein reaches the large intestine undigested, the gut bacteria must break it down through fermentation. This task produces various gasses including hydrogen, methane, and in some cases, sulfur compounds. “This process can increase the volume and odor of flatulence, especially if there are already gut imbalances,” Smith says. 

3. Dehydration

If you've recently upped your protein intake pretty dramatically, while also upping your time spent exercising (as one might when trying to put on muscle), hydration may be part of the problem, Jones says. “Those with an ‘all-or-nothing’ mentality in the gym may also be more likely to go on strict low-carb diets, reducing intake of healthy plant foods that support normal digestion, leading to an increase in digestive distress,” Jones says. Consuming more protein and less carbs may increase fluid needs, she continues, “and not increasing fluid and electrolyte intake appropriately can also lead to constipation.”

4. Enzyme Overwhelm 

The body has specific enzymes to break down proteins. A sudden increase in protein can temporarily overwhelm these enzymes, leading to incomplete digestion, according to Smith. And again, when proteins aren't fully digested in the small intestine, they reach the large intestine and end up producing gasses.

5. Increased Saturated Fat Consumption 

“If your new high-protein intake also comes with a higher fat intake, both of these nutrients can lead to a slowdown in gut motility, which could contribute to gas output,” Nielsen says. This is especially true if that fat is saturated fat, which can also be challenging to digest and absorb in large amounts, Jones says. Sure, that 16-ounce ribeye at a steakhouse looks like a win at 90 grams of protein, but the 80 grams of fat stresses the digestive tract, often resulting in more proteins reaching the lower digestive tract and causing undesirable gas.

6. Sulfur-Containing Amino Acids

Foods high in protein—especially animal proteins like meat, eggs, and dairy products—naturally include sulfur-containing amino acids, including cysteine, methionine, and taurine. “When these amino acids are broken down in the gut, they can produce hydrogen sulfide, a gas that gives farts their characteristic unpleasant odor,” Smith says. 

7. Ingredient Intolerance 

Whey and casein protein powders, “which are popular among fitness enthusiasts,” according to Smith, are derived from dairy and may contain lactose. It's estimated that nearly 70 percent of the world’s population has difficulty digesting lactose. For these populations, consuming lactose can lead to increased gas production, bloating, and flatulence, Smith says.

Beyond that, many protein supplements contain artificial sweeteners such as sugar alcohols (erythritol and sorbitol are two common examples), which tend to be difficult to digest and can ferment in the gut, leading to gas and bloating.

“I encourage my clients to try to stick to proteins with minimal ingredients and look for ingredients that they recognize and/or can pronounce,” Smith adds. 

Are Protein Farts Normal?

First things first: Gas as a general concept is totally normal. It’s actually an indicator of a healthy, functioning digestive tract, Nielsen confirms. It’s normal to pass gas every day; in fact, the average person passes gas 14 times each day.

Any substantial diet changes—including a rapid increase in protein intake—can slow digestion slightly as the body acclimates to its new normal, Nielsen says. So if you notice an increase in gas, or gas aroma, for a couple of weeks and then things return to their usual levels, your body is responding just as planned.

“Long-term protein farts aren’t a universal experience though, so it’s worth being curious,” Nielsen says. “Keep a food and symptom journal for a week or two to try to pinpoint what the culprits might be.”

Perhaps your pre-workout snacks are a bit too protein-strong, and having that food in your gut during a tough running or cycling workout is triggering indigestion. Or maybe you’re not drinking enough water throughout the day, which can cause sluggish digestion. Those extra eggs and cheese sticks could also be crowding out your more fibrous noshes, so you’re experiencing constipation or gas.

“It’s also really important to focus on balance, even if your diet is protein-heavy,” Smith says. “Include fiber-rich foods like complex carbohydrates, vegetables, and fruits as well as healthy fat and adequate fluid to help support bowel regularity, which can help reduce the effects of protein farts if they are a result of constipation.”

While protein farts can be a common side effect of increased protein intake and often aren't a cause for concern, they could be a red flag for you to fine-tune your diet. Balance, moderation, and experimentation (say, swapping protein powder for a whole-food protein source like chicken) are often helpful to keep top of mind if you notice that the protein farts are persistent.  

Symptoms like protein farts are neither “good” or “bad,” Nielsen says. “They just are! If that’s all you are noticing from your dietary shift but it doesn’t really bother you, and isn’t combined with any other troubling symptoms, you could just give your body some time and see if it adjusts,” she says.

That said, if protein farts do bother you, there are some things you can do to prevent them.

Can You Prevent Protein Farts?

As we mentioned, gas is a totally normal part of being alive. But if your protein farts are particularly frequent or smelly, try any or all of the 12 steps below to get things under control:

1. Go Gradually

As you embark on adding more protein to your menu, do so one meal or snack at a time. For example, you might add an extra protein source to breakfast as you keep the rest of your day’s menu consistent for a week. Then pack your breakfast and post-workout snack with protein the next week. “This gives your digestive system time to adjust to the increased protein load,” Smith says.

2. Take a Break From Packaged Foods 

Many busy individuals on a high-protein diet turn to packaged items like bars and shakes, not realizing that they’re sensitive to the large amounts of prebiotic fibers, sugar alcohols, or dairy in the mix. Swapping in plant-based protein foods such as nuts, seeds, quinoa, or even beans may tackle two problems at once: increasing fiber and eliminating intolerance.

3. Balance Your Diet

You already know that fiber aids digestion and can help regulate the gut microbiome. And “don't neglect carbohydrates and healthy fats, as a well-rounded diet aids overall digestion,” Smith says.

4. Stay Hydrated

Aim to drink about half of your body weight (in pounds) in ounces of water each day. So if you weigh 160 pounds, shoot for 80 ounces daily. Proper hydration supports digestion and the integration of nutrients, including protein, Smith explains.

5. Choose Lean Protein Sources

According to Smith, lean meats (like chicken, turkey, and fish) and plant-based proteins (like lentils, chickpeas, and quinoa) are generally easier to digest than saturated fat-rich meats.

6. Try Different Protein Types

If you use protein supplements, play around with them. Plant-based or dairy-free protein powders might be a better fit for your gut than whey or casein protein, which have been linked to slower gastric emptying. (If you take this route, a smart place to start is selecting an option listed in the National Sanitation Foundation’s Certified for Sport® directory.)

7. Eat Smaller, More Frequent Meals

Consuming small amounts of protein throughout the day instead of large amounts in one sitting can ease digestion and give your body enough time to utilize the protein for muscle-building rather than energy storage.

8. Tune In to Avoid Gas-Triggering Foods

Each gut responds differently, but some people may find that certain protein-rich foods like beans and lentils produce more gas. Rather than sticking to the same routine each day or week, aim to be mindful of how your body reacts to different foods and eliminate any of your personal protein-fart generators.

9. Move Your Body

“Regular physical activity can improve your digestion and reduce bloating,” Smith says. The World Health Organization (WHO) suggests shooting for at least 30 minutes of moderate cardiovascular activity five days per week, plus two days of total-body strength training.

10. Prioritize Probiotics

Consuming probiotic-rich foods like yogurt, kefir, and fermented vegetables (or taking a probiotic supplement if your healthcare provider advises it) can support gut health and potentially reduce gas of all kinds, Smith says, including protein farts.

11. Try Ginger

If you think that your gas might be caused by sluggish digestion, try adding about a 1-inch piece of peeled fresh ginger to a smoothie or grating it into oatmeal. “Ginger is pro-kinetic, meaning that it helps facilitate the movement of the gut,” Nielsen says. “It's a great food-based digestive aid.”

12. Consult a Dietitian

Persistent and excessive amounts of gas might be a sign of a gut imbalance, so it’s wise to work with a registered dietitian to identify your potential triggers if your body doesn’t seem to adjust to increased protein intake. “If the gas is excessive or accompanied by discomfort, bloating, or other symptoms,” Smith says, definitely speak to a dietitian for personalized guidance.

The Takeaway

Gas in general—including the more frequent or more odorous protein farts that can be associated with increased protein intake—can be annoying and embarrassing. In most cases, protein farts go away in a few weeks after you begin to consume more protein. If they persist or are impacting your quality of life, try focusing on hydration, diversify your protein sources, choose leaner proteins over fattier ones, integrate physical activity into your daily agenda, consume probiotics, and add protein slowly but surely—rather than all at once. If you notice that protein farts come in tandem with excessive bloating, discomfort, or other unwelcome side effects, chat with a dietitian. Hopefully, things should calm down before long.

This content is for informational and educational purposes only and does not constitute individualized advice. It is not intended to replace professional medical evaluation, diagnosis, or treatment. Seek the advice of your physician for questions you may have regarding your health or a medical condition. If you are having a medical emergency, call your physician or 911 immediately.


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