What really happens to your body when you eat only meat
The carnivore diet promises clarity and quick results—but experts say the long-term effects on your heart, brain, and gut could be far more complicated.
Scroll through the feeds of carnivore diet influencers and the picture is stark: towering plates of steak, butter-slicked burgers, ribs stacked on slabs of wooden chopping boards. Greens are nowhere to be seen—not even as garnish.
The carnivore diet takes “low-carb” to its extreme, eliminating all plant foods in favor of meat, eggs, and dairy. Some adherents go further, living almost entirely on red meat.
Proponents of the diet claim it leads to rapid weight loss, clear skin, reduced bloating, and even remission of autoimmune conditions, though these claims have not been validated in clinical trials. Others frame carnivory as reclaiming an ancestral way of eating, channeling Paleolithic hunters who thrived on animal protein.
But today’s industrial meat supply—and the global food system it feeds—is far removed from that imagined past. The United Nations estimates that one-third of global greenhouse gas emissions originate from the food sector, with meat consumption being the single largest contributor.
Yet, despite its rising visibility on platforms like Instagram and TikTok, meat-only diets remain a fringe trend. A 2023 report by the Good Food Institute found that nearly 60 percent of U.S. households purchased plant-based foods. Over the past decade, the number of consumers identifying as “flexitarian” has roughly doubled.
(Do you want to eat more veggies in 2025? Read this.)
Sociologist Richard Twine says this trend’s growing popularity is more than just about food. He argues, “The increased social media visibility of the carnivore diet demonstrates a backlash of widespread calls for dietary change.” He adds that loading their plates with meat has become not just a diet, but a statement: a rejection of sustainability, public health advice, and mainstream ideas of what responsible eating looks like.
So, what really happens when you abandon broccoli and bread for beef alone? Is the carnivore diet a biologically sound path to health—or just another trend dressed in primal clothing?
How the carnivore diet affects your gut
Among the first changes people report when on the carnivore diet is their digestion—less bloating, less gas, and a trimmer waistline. However, with no long-term clinical trials on carnivore diets, most health claims remain speculative.
When carbohydrates vanish, the body turns to its glycogen stores—chains of glucose tucked away in muscle and liver—for energy. As those stores burn off, they release water, leading to rapid weight loss that’s mostly water, not fat.
Soon after, the body enters ketosis, a metabolic state in which fat becomes the primary fuel source. Ketosis also suppresses hunger hormones and boosts signals of fullness, which helps explain why many carnivore dieters report feeling lighter, leaner, and less hungry in the first few weeks.
Gastroenterologist Wendi LeBrett says that it’s not uncommon for individuals who adopt the carnivore diet to report a reduction in bloating and gas. However, that relief may have less to do with the absence of vegetables than with the absence of certain fermentable fibers—particularly high-FODMAP foods, which are known triggers for some people.
(Here’s how cutting out certain foods can trigger new allergies.)
A 2022 randomized crossover trial found that a low-FODMAP diet significantly reduced abdominal pain, bloating, and stool irregularities in adults with irritable bowel syndrome. LeBrett says similar relief can often be achieved through following a low-FODMAP diet, without resorting to the extreme elimination of all plant-based foods.
There is a catch, though: removing fiber for extended periods can reduce the body’s tolerance to it. “The next time they eat a plant-based food, their gut may overreact because it has lost the skillful bacteria which help digestion of that food, producing more symptoms and reinforcing restrictive habits,” says nutrition scientist Emily Prpa.
She emphasizes that fiber isn’t just about digestion; it’s integral to long-term health. “Fiber is one of the most protective components of the human diet, linked to lower risks of heart disease, cancer, diabetes, and even improved longevity and cognitive health,” she says. A 2023 comprehensive review of dozens of studies found that high fiber intake reduces overall cancer risk by up to 22 percent, including a significant protective effect against colorectal cancer.
“Ultimately, removing fiber entirely strips away one of the best defenses we have for both body and mind.” Prpr says.
What your body loses on a meat-only diet
But digestion is only one part of the story—inside the body, the absence of plants triggers a cascade of nutrient losses. Without fruits, vegetables, and grains, the body loses access to crucial nutrients—vitamin C, antioxidants, and plant-based compounds known as phytonutrients—that help fight inflammation and support long-term health.
The high protein intake in carnivore diets also places extra strain on the liver and kidneys. The liver must work harder to convert excess nitrogen from protein into urea, which the kidneys then filter out; this process is linked to an increased risk of kidney stones and long-term organ stress.
(What really happens to your body when you give up meat—even just briefly.)
Prpa notes that the brain may be another overlooked casualty. “Diets rich in fiber from plant foods, like the Mediterranean diet, are linked to better mood, lower depression risk, and protection of brain health,” she says. Supporting this, recent meta-analyses found that following the Mediterranean diet reduces depression risk by about 19 percent. In comparison, a five-gram increase in dietary fiber corresponds to a 5 percent reduction in the risk of depression.
Can the carnivore diet harm your heart?
Cardiologists have long warned against diets centered on red and processed meats, which are high in saturated fats and cholesterol. These components have been linked to elevated LDL (“bad”) cholesterol levels, a key risk factor for cardiovascular disease. A 2021 cohort study of over 180,000 participants found that high red meat consumption was associated with a 20 percent increase in cardiovascular disease risk, a 53 percent rise in heart disease, and more than double the risk of stroke-related mortality.
(Even a small amount of red meat can increase your diabetes risk.)
“The absence of fiber eliminates one of the body’s natural tools for lowering LDL, since soluble fiber binds cholesterol in the gut and helps remove it from circulation,” says Prpa. Given that LDL is one of the most consistently causally linked drivers of heart disease, the long-term cardiovascular risks of this diet are a very real concern.”
Why elimination diets feel safe
Despite these risks, the carnivore diet continues to find an audience, particularly among individuals frustrated by chronic digestive issues, food intolerances, or autoimmune symptoms.
“Many are drawn to its simplicity and the appeal of elimination-style eating,” says Prpa. “Some try it for quick fixes or to relieve gut symptoms, thinking that cutting out foods will ‘reset’ their system.”
In the short term, it often delivers, especially for those who previously consumed large amounts of ultra-processed foods. But the long-term health trajectory remains uncertain.
“What concerns me most about the carnivore diet isn’t necessarily what it includes,” Prpa says, “but what it leaves out.”
