Why Do People Feel Better on a Carnivore diet? (And Why It's Not the Reason You Think)

I was talking to my mum a few weeks ago about a friend she'd just been on holiday with. My mum stopped eating meat around the same time I went plant based, so we talk about this stuff a fair amount. Her friend is someone who loves the outdoors, spends his weekends birdwatching, cares deeply about the environment. Exactly the kind of person you wouldn't expect to end up on the carnivore diet. But he had, and he was preaching the benefits like he'd just found religion - brain fog gone, joints not aching anymore, more energy than he'd had in years.

My mum is incredibly smart, and as a doctor, has a healthy amount of cynicism about these things. And even she was struggling to argue with what she was hearing, because he genuinely seemed better. That's what got me thinking about this properly. How is it possible that a diet which is, on paper, the exact opposite of everything we've been told for decades, is producing this much positive feedback from real people who don't seem to be lying about how they feel?

So I went looking into what's actually going on, because dismissing it outright felt intellectually lazy, and so did accepting it at face value.

The feeling is real. The explanation people give for it usually isn't.

This is the bit I want to get across clearly, because it's more interesting than "carnivore good" or "carnivore bad." When someone drastically restricts their diet down to meat, eggs and maybe some dairy, several things happen at once, and almost none of them are unique to eating that way.

There's a study from 2026 that I think explains a huge part of what's happening with my mum's friend, and with carnivore testimonials generally. Researchers took 112 people with low mood and split them into four groups. One group ate a genuinely improved, fresh food diet. A second group got food with a similar nutritional profile but were told less about how good it would be for them, so their expectations were lower. A third group did a cooking intervention with no real nutritional change at all. The fourth group was a waitlist control. All three active groups improved compared to the people on the waitlist, and there was no meaningful difference between them. The food wasn't the deciding factor. Doing something, having a structure, believing it would help, was.

There's a similar pattern with weight loss, which tends to be one of the first things people notice on carnivore. Simply tracking what you eat, regardless of what the food actually is, is associated with greater weight loss in the research. Self-monitoring on its own, the noticing and the paying attention, seems to do a lot of the work before the specific diet rules even come into it.

Then there's the water weight. Carnivore diets are essentially carbohydrate free, and cutting carbs drains the glycogen stored in your muscles along with the water that's bound to it. That produces a fast, visible drop on the scale in the first week or two, and it feels like enormous progress, even though it isn't fat loss.

The accidental elimination problem

This is the part that I think explains a lot of my mum's friend's story specifically. When you cut out almost every food group at once, you often remove whatever was actually causing your symptoms without ever finding out what it was. It's the same mechanism behind why people feel better going gluten free. In a lot of cases it's not the gluten itself, it's the fermentable carbohydrates that happen to travel alongside gluten in wheat, the FODMAPs. Gluten just gets the blame because it's the label on the diet. Carnivore does the same thing on a much bigger scale. If someone has an intolerance, an undiagnosed gut issue, a sensitivity to a specific food group, going carnivore will remove it along with everything else, and the relief will feel enormous. That's not evidence that meat healed them. It's evidence that whatever was bothering them is gone, and there was likely a far less extreme way of finding that out.

What the actual evidence on carnivore says

I want to be fair here, because I think a lot of health content either ignores the research entirely or overstates it in the opposite direction. The honest answer is that we don't have much carnivore specific evidence at all. A 2026 scoping review looking specifically at the carnivore diet found only nine human studies had ever been done on it. The researchers described the evidence as very limited, the studies small and short term, mostly without proper control groups, and they flagged recurring concerns around inadequate vitamin C, vitamin D, calcium, magnesium, iodine and fibre. Their conclusion was that long term adherence to carnivore currently cannot be recommended, not because it's been proven dangerous, but because there simply isn't the evidence to say it's safe either.

What we do have is much stronger evidence on the individual pieces carnivore removes or maximises. Fibre is a big one. A 2023 meta-analysis of prospective studies found that people with higher fibre intakes had around a 23 percent lower relative risk of dying from any cause over the study periods, along with lower cardiovascular and cancer mortality specifically. Carnivore removes fibre completely, because it removes every plant food. On the other side, carnivore diets often end up extremely high in saturated fat, and a 2026 review of 17 randomised trials involving over 66,000 people found that reducing or swapping saturated fat for unsaturated fat lowered cardiovascular events. None of this proves that carnivore itself shortens your life. But it does mean the claim that fibre is unnecessary, or that saturated fat doesn't matter, isn't consistent with what the wider evidence base is showing us.

There's also a longevity angle I find useful when people bring up ancestral eating, which comes up a lot in carnivore circles. None of the Blue Zones, the regions in the world where people live the longest and healthiest lives, eat carnivore. Grains, legumes and fibre are core to every single one of them - they are predominantly plant based. And the ancestral argument itself tends to leave out a lot of nuance. Humans historically ate close to carnivorous in some contexts, but that meant eating the whole animal including the organs, and specific preparation methods that most modern carnivore plates of steak and butter don't come close to replicating.

Where I've landed on this

I don't think my mum's friend is imagining his results, and I don't think anyone posting a genuine short term carnivore success story online is lying. What I think is happening is that they've made several changes at once, cut out ultra processed food, started paying attention to what they eat for the first time in years, possibly removed a food that was genuinely causing them problems, and given themselves a strong sense of structure and belief that this was going to work. All of that produces real, measurable improvements in how someone feels. None of it requires giving up plant food to get there, and the current evidence suggests that doing so long term comes with real trade-offs around fibre, micronutrients and the plant compounds that don't have an animal food equivalent.

But zoom out from any one person's testimonial and look at the weight of evidence sitting behind generations of people across entire countries and regions, and it becomes hard to find a single qualified nutrition professional who thinks carnivore is a sensible way to eat for the long term. Not because they're closed minded or married to an old way of thinking, but because the evidence keeps pointing the same direction - fibre matters and variety matters. The specific compounds plants give us, the antioxidants and polyphenols with no direct animal food equivalent, matter. Even the sheer enjoyment of food, the texture of a good sourdough or the way a ripe mango tastes in summer, matters for a life you actually want to live. When you put all of that together and then ask why anyone would deliberately strip it all away in favour of steak and butter three times a day, I genuinely struggle to find a good answer.

If you've had your own version of this, a diet that made you feel unexpectedly brilliant and left you wondering what was actually going on, that's exactly the kind of thing I love working through with clients. Untangling what genuinely helped from what just felt good in the moment, and building something you can actually sustain without needing to remove entire food groups to get there. If that sounds like where you are, get in touch and we can figure it out properly.