Carnivore Challenge Preliminary Results Are Good (weight down, waist down, pulse down)


This is the first post. The next post is here Carnivore Challenge Preliminary Results (poop, sex, activity)

Could you live on only one food? Even if you could, why would you want to? Wouldn’t eating just one food make you sick? Even if you can eat just one food, and it doesn’t make you sick, it’s got to be super boring, right?

Well, not too get too scientific too fast, but the technical answer is that nobody really knows!

The science on what people eat isn’t very good and none of it addresses single-food diets. Single-food weight loss diets are basically a punchline, like the Grapefruit Diet or the Potato Diet. There’s plenty of evidence that you cannot live a long and healthy life eating just one plant (hence the weight loss).

However, there is compelling evidence that you can live a long and healthy life eating only meat. Or at least eating only meat for long periods of time (months or years). You can find a lot of anecdotes if you go looking for them, particularly if you look into diets like paleo, keto, and low carb. Eating only meat is called Carnivore or Zero Carb and it’s sort of like super paleo or extreme low carb.

There’s a whole rationale for why you might try eating nothing but meat that I’m not going to go into here. What I want to get into is the hundreds of people who tried it and who shared their data with us.

First, a little background. I was experimenting with a little nutrition tracker I made. I thought it might help answer the question:

How do I get healthy when the stuff I tried before didn’t work?

I saw millions of people let down by current nutrition and exercise advice that was one-size-fits-all. I had a vision of each person solving their own unique problems by running experiments on themselves. It doesn’t matter what the authorities think should probably work. What matters is what works for you.

Then I met Shawn Baker and he saw the same problem and had the same idea about how to fix it! Between bites of steak we plotted the overthrow of conventional wisdom. You see, Shawn, and myself, and many others, had been eating only meat and were healthier than ever.

This didn’t add up. According to the textbooks we should all be sick or dying. As of this writing Shawn is still improving on his world record athletic performance at age 50.

We’re not interested in finding the one diet that’s perfect for everyone. It probably doesn’t exist. What we’re interested in is finding out what the options really are.


Shawn put out a request for people who wanted to try eating meat for 90 days. He got hundreds of positive responses, so I rebuild the experimental tracker and hosted it at The idea was simple: get people to write down what they did and what the results were.

Bottom line up front, based on a simple analysis of the self-reported data we can see important improvements in health. Over 90 days our carnivore diet experimenters, on average, decreased their body weight by 30lbs (14kg), their waistline by 3in (8cm), and their resting heart rate by 8bpm.


You can actually check out some of the data yourself in real time. The pages that describe the rules of the challenge(s) also show some statistics. The numbers aren’t old. They’re calculated when you load the page based on the most recent data available. Like a live infographic. You can see graphs of specific data points at the bottom of the page.

I’m working on making this living infographic better. This is citizen science. All of the data you track in Track-well goes into the same data set. The more you use it, the more you learn about yourself. The more we use it, the more questions we can answer.

I’ll be publishing more complicated analysis of the challenge data (still learning and building).
Leave a comment and let me know what you’d like to see next.

Hokay, so, here’s some crisp new data. The first question is, of course, how much meat did the participants eat? That leads me to an important caveat which is that I can only say how much people logged. I don’t actually know what they did, only what they voluntarily reported. That being said, the numbers seem to remain consistent even as the total volume of data logged decreased throughout the 90 days, so it’s probably reliable. The [value_count] line is how many separate entries went into the calculation of the [value] line.

Based on at least 58 users each day we show about 800-1000g (1.75-2.2lbs) per person per day. That makes sense as that’s about 2,000cal per day, give or take. My guess is that the slight increase in amount over the study is related to the increase in noise, probably because of the decreasing number of user logging.

This finding seems to support the protocol guideline of eating when hungry, not over eating, and especially not under eating in an attempt to lose weight. As we’ll see in the next graph, on average people ate an appropriate number of calories and lost weight, indicating their weight might have been held artificially high by the way they were eating before. At least it doesn’t undermine that idea.

A lot of people have some weight to lose so the next most popular question is what happens to body weight on a carnivore diet? Based on a simple average it looks like a decrease in weight over time, from an average of about 90kg to about 76kg. That’s 14kg (30lbs) or about 5kg (10lbs) per month.

It’s kind of neat to see the pulses in the total number of values. Some people are logging their weight every day and some are logging only when Track-well prompts them to (about once per week).

Personally, the difference between body weight and waist circumference as markers of health is one of my pet peeves. I’d rather people tracked their waistline since body weight glosses over composition (lean vs fat). Here we see another decrease over time. From about 94cm to about 86cm. That’s 8cm (3in) or about 2.5cm (1in) per month.

Along the same lines as waist circumference, I’m a big fan of performance markers as indicators of health. Keep in mind this diet plan (eat meat drink water) doesn’t direct any exercise. It’s generally safe to assume people who are trying to improve their health are probably doing more than one thing to improve their health, and with Shawn posting rowing records that’s an even better bet. At any rate, the data shows a modest decrease in resting heart rate from about 70bpm to about 62bpm. That’s 8bpm or about 2.5bpm per month.

According to the first study I found [link], a 10bpm decrease in resting heart rate translates to a 16% lower risk of dying. Since our users clustered at around 50 years of age that’s a significant improvement in their health.

Taken together I think this is a good indication that a carnivore way of eating deserves more attention than it’s received so far. At a minimum, it should put to rest all the fears that carnivores get scurvy :slight_smile:

It’s also a win for citizen science! People are going to be trying stuff anyway. If we can get a few of them to track what they’re doing we can explore a whole lot more options than if we sit around waiting for official studies. If you want to try the carnivore challenge yourself it’s available at Track-well. The plans are built so that you can follow them at any time; you don’t have to wait for a group start date.

I’d love to get more large groups to follow the same eating plan so we can start to compare what works.

Carnivore Challenge Preliminary Results (poop, sex, activity)