Could A High-Protein Diet Ruin Your Gut?

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Justin Pumfrey

We are living in the age of the high-protein diet. It’s in everything—supercharged coffee, high-performance snack bars, even hidden in popcorn. Social feeds are thick with 100-grams-per-day declarations, but somewhere along the way, carbs became the villain of the wellness story. For some, what started as a clinical macronutrient has morphed into a personality trait—and a slightly obsessive one.

But behind the aesthetic promise of the high-protein diet (leaner limbs, glossier hair, the sacred metabolic boost), there’s a quieter story playing out in the gut.

According to nutritionist Payal Kothari, author of The Gut, the rise of the high-protein diet has been driven by a mix of vanity and virality. “Social media, aesthetic goals, and the fashionization of gym culture have glamorized protein to the point of obsession,” she says. “The fear of carbs and the belief that protein equals weight loss or muscle gain is everywhere. While protein is essential, this obsession is often overblown, especially when it overshadows fibre, healthy fats, and diversity in the diet.”

The math itself is revealing. For most non-athletic adults, Kothari says, “the requirement is about 0.8 to 1.2 grams of protein per kilogram of body weight.” A far cry from the triple-digit figures often peddled online. “Influencers often push 100 grams plus daily, which may suit bodybuilders but overwhelms the average person’s gut and kidneys, especially if not balanced with fiber, water, and movement,” she adds.

So what happens when you lean too far into the high-protein diet? “The gut loves diversity and fibre, not just meat,” says Kothari. “A meat-heavy, fiber-poor diet fuels bacteria that produce inflammatory compounds like ammonia and trimethylamine. This can trigger bloating, constipation, and even gut lining damage, especially when red meat dominates your plate.”

In short: your microbiome wants a buffet, not a single-food obsession. And when the fiber’s missing, things go downhill—fast. “When intake goes above 2gms per kg of body weight, it can overwhelm digestion and produce harmful byproducts in the colon. Without fiber to balance it, excess protein ferments poorly, also leading to bloating, migraines, and disrupts the microbial ecosystem completely.”

It’s not just about numbers, either. It’s about how that imbalance shows up in your everyday life. “It slows everything down,” Kothari notes. “You’ll likely feel constipated, gassy, or even foggy. Fiber is the food for your good bacteria. Without it, your gut bugs starve, and digestion becomes sluggish and inflamed.”

Some of the early signs of a gut under siege from a high-protein diet? “Smelly gas, bloating, constipation, acid reflux, liver dysfunction, or feeling heavy after meals,” she says. “If you’re also more irritable or sleeping poorly, your gut may be inflamed from the imbalance.”

None of this is an argument against protein; rather, it is a reminder to play the long game. “A balanced plate should include clean proteins like lentils, broccoli, tofu, cheeses, eggs, colorful veggies, healthy fats like ghee or nuts, and complex carbs like quinoa or sweet potato,” says Kothari. “Add fermented foods and prebiotics to boost gut flora. Build muscle, not gut imbalances.”

And if you re in damage-control mode after going all-in on the high-protein diet? Kothari recommends reintroducing fiber-rich foods slowly: “chia seeds, veggies, fruits, legumes.” Her advice: “Swap one protein-heavy meal for a plant-based one daily. Use herbs, spices, and fermented foods. You won’t lose results—you’ll gain better energy, digestion, and long-term success. Overloading protein can be dangerous to your health.”

Of course, there are gut-friendly, high-protein foods that do offer something more symbiotic. “Unflavored Greek yoghurt, tempeh, kefir, and miso offer both protein and probiotics,” says Kothari. “They help buffer the gut from inflammation, but they can’t replace fiber. Think of them as helpful passengers, not the driver.”

Protein, then, isn’t the villain. But the high-protein diet, when taken to extremes, might just need a fiber-fuelled reality check.