Denise Minger’s Metabolic Swamp
If you’ve read my blog for a while you know I’m obsessed with the “metabolic swamp.”
The term was coined (as far as I know) by Denise Minger in her 2015 blog post In Defense of Low Fat.
Minger was a big paleo/low-carb writer at the time, I believe. In my memory she’s most famous for taking down T. Colin Campbell’s vegan-ideology-tinted book The China Study. But as she points out in that post, we can’t just put on our own ideological goggles and ignore the clear results that some people are getting with the low-fat equivalent of keto.
She lists Walter Kempner of Rice Diet fame, for example, a controversial guy who fled the Nazis and became a professor at Duke University. He used a diet consisting mainly of rice, but also sugar, fruit, and fruit juices. This led to rapid recovery in many of his patients suffering from hypertension, diabetes, and even pretty massive fat loss.
He is controversial because his methods appear to have been somewhat.. archaic. I guess these were different times. He apparently whipped some of his patients “consensually” to induce sufficient motivation in them to continue the diet. He got sued.
That said, this doesn’t seem to have been the case for all of his success cases. The diet seems to have worked pretty great on its own for many people, if maybe not all.
Minger concludes that, if we just observe the anecdotal landscape, the Standard American Diet is pretty mixed between fat & carbs. People on both the very-low-carb (keto) side and the very-low-fat (“carbo”, my term) side tend to experience somewhat “magical” weight loss without limiting total energy intake too much, suffering, applying massive amounts of discipline/willpower, or counting calories.
She named that mix of fat & carbohydrates the “metabolic swamp” that you should stay out of by sticking either a low-fat or low-carb diet:

Unfortunately, it seems that the low-fat space has been somewhat captured by ideological vegans. This made it easy for low-carb/keto people to dismiss any evidence for low-fat, even when it happened to be right.
I used to be one of those people. 5 years ago, if you told me that people can eat 80% carbs and not only reverse their obesity but also their diabetes, I would’ve assumed you’re lying.
But I have seen enough anecdotes from people I trust to have changed my mind, and Minger’s Swamp is the best explanation I’ve seen to date.
Triangular Swamp: Adding Protein
Minger’s original swamp does not include protein.
If you know my “origin story” you know that I am somewhat of a recovering ketard. Or maybe I should call it post-keto.
What I mean is: I still do keto, but I no longer believe it is necessary or sufficient for fat loss.
I gained 100lbs back doing strict keto. There are things a man can believe after gaining 100lbs in strict ketosis, but “keto is necessary or sufficient for fat loss” is not one of them.
Pretty accidentally, I found out that severe protein restriction seems to be the magic bullet for me, and that there’s actually quite a bit of science behind it. Later, I learned about seed oils and how they play into all of this.
And one thing that many of the low-fat/vegan type people typically do is also to eat pretty low protein, especially “high quality” animal protein.
(I’m putting “high quality” animal protein in quotes because, while that is true, the high quality might actually be bad for our protein-restricting purposes.)
The aforementioned China Study book by vegan T. Colin Campbell explicitly claims that animal protein is uniquely harmful. If I remember correctly (it’s been a decade that I read it, I was briefly a vegan before even doing Paleo/low-carb), he studied casein feed in mice or rats and extrapolated the harm done to all animal protein.
I have since seen pretty good evidence that casein, at least the type or way they feed it to lab animals, is uniquely bad. Chris Masterjohn has reproduced some mouse studies with egg white protein, and none of the alleged effects happened. So casein, like lard, might be uniquely bad in rodent studies.
Anyway, it behooved me to ask: what would the Swamp look like if we also added protein to the mix?
We could imagine this “triangular swamp” something like this:
Adding the 3rd macro, protein, presents a certain challenge: whereas humans can and do eat pretty much any diet between 100% to 0% carbs or fat, we cannot actually do that with protein. Observing ancestral human populations, there are pretty much none that eat more than 30% or so of protein.
Unlike felines, our ability to turn protein into energy (via gluconeogenesis) is quite limited, and it has a bunch of side effects. We simply didn’t evolve to do it well, although some of us do it better than others.
This immediately shuts off a pretty big part of our new triangular landscape. Let’s mark everything above 30% protein as “too much” because we almost never see it sustained in human populations.
Everything above 50% we’ll call “rabbit starvation” because I actually have never seen any population studied that did this. The only people eating even close to 50% protein are bodybuilder types eating an extremely calorically restricted diet, like the PSMF (Protein Sparing Modified Fast).
Yes, you can eat 50% protein. But it probably means your total energy intake is extremely low, changing the denominator of the equation.
This cuts off over half of the triangle:
Keto & Carbo
Now let’s add our contenders at the extreme ends of the remaining spectrum.
Keto is often defined as eating more than 80% of your total carolies from fat. That’s not necessary a super precise or correct definition. Some people might be in some level of ketosis eating 75% from fat. Some might need to restrict protein/carbs more than others.
There are even people claiming that being in ketosis is not the hallmark of a keto diet (really???) and that if you just eat low-carb enough even with very high protein, that’s still somehow “keto.”
For simplicity’s sake, let’s just use “80% or more from fat.”
“Carbo” isn’t a real thing, it’s just a convenient way to say “the carb equivalent of keto” aka 80% or more of carolies from carbs. It also doesn’t come with any of the ideological baggage of veganism or “Whole Food Plant Based,” although a carbo diet would have to be largely plant based.
Let’s put both keto and carbo into the landscape:
Low-fat & low-carb
Now let’s expand a little and go into the not-quite-as-severe regions that we’d still consider outside the swamp.
Low-carb & low-fat diets could be described as restricting the respective macros to 30% of your total energy intake or less. I’ve seen some definitions starting at around 25% as well, but let’s stick to 30% for simplicity, and because my grid doesn’t have 5% steps.
The swamp is starting to shape up!
Note that the “angles” of the borders of low-fat and low-carb are sloped differently than those of keto/carbo. They are not sloped “toward carbs/fat” but instead “away from carbs/fat.” This is because we defined keto/carbo to be >80% of the respective macros, yet we’re defining low-carb/fat as <30% of the OTHER macro.
Again, one could quibble over the details. This is just a rudimentary attempt at analysis and visualizing the whole landscape.
Enter The Swamp (j/k, don’t!)
Now we can finally see the vague shape of our nemesis, The Swamp. The Swamp is simply that space in the landscape left over after we subtract low-carb and low-fat:
We can see the swamp lies roughly between >30% carb and >30% fat, with <30% coming from protein. (Anything higher protein would approach a sort of PSMF, which isn’t sustainable for most people, and would likely not be a long-term ad-lib diet.)
I would actually be interested in seeing if the very-low-protein part of the Swamp would work for some people. Imagine eating 47% carbs and fat each, and about 6% protein. Would that still present problems, or work out fine because the protein component is so restricted?
Placing various crazy internet diets
ex150
ex150, my heavy cream diet, is a little tough to place on the grid because it doesn’t confirm exactly to the 10% steps. It’s about 90% fat, but the remaining 10% are roughly split between carbs and protein. According to my calculator, I’m eating 6% protein and 4% carbs.
Due to the 10% grid I’ve made, I have to pick either 90% fat/10% protein or 90% fat/10% carbs, neither of which is quite correct. But oh well, either of them is close enough.
So, as expected, ex150 is pushing just about as hard into the keto corner as you can.
Potato Diet
Promoted by people like Slime Mold Time Mild with their infamous Potato Trial, the potato diet consists of eating.. well, potatoes.
People are not in agreement about why the potato diet works so well for so many people, but it certainly sounds low-fat and low-protein and out of the swamp, so I suspect that could be a major factor.
Potatoes are about 90% carbs and 10% protein, with only 1% fat. Eating them exclusively is almost the carb-equivalent of ex150. It’s even a little less mixed, because you only get 1% fat, whereas heavy cream is about 3% carbs/protein each.
Standard American Diet
According to the NHANES survey from 2017-2018, the Standard American Diet is currently about 16% protein, 36% fat, and 47% carbohydrates.
Again these don’t fit super neatly onto the graph, and it’s probably still bad if you’re a few percentage points off. So I’ve just put it in as a little triangular area, of 10-20% protein, 40-50% carbs, and 30-40% fat.
As you can tell from 36% fat and 47% carbs, the SAD isn’t exactly in the middle of the swamp. It’s a little bit biased toward carbs. It is also neither very high (20-30%), nor very low (<10%) in protein.
This is probably due to palatability. Both very protein-restricted and very-high protein diets become somewhat unpalatable and make dining out & cooking very difficult.
Remember, we saw that even plain potatoes are at 10% protein! If you eat a starch based diet from potatoes, wheat, rice, or other staples, you’re going to have a very hard time getting <10% protein, even if you’re eating zero meat and dairy. It’s easier with fruit or hacks like heavy cream, but fruitarianism and ex150 aren’t exactly what the Standard American would consider a super delicious sounding diet.
On the higher end, toward 20-30% protein, we quickly get into the “dry chicken breast & broccoli” diet of bodybuilders. This also requires an infamous amount of willpower to stick to.
Conclusion
Mapping out the swamp was a fun exercise and forced me to explicitly formulate some ideas that had only been vague and implicit in my mind. For example, where exactly does the SAD fall? Where does low-fat or low-carb begin and end? Is 50/50 between fat/carbs but 0% protein still “swampy?”
I think this is still a pretty basic and rough draft, but I do like to see it. Helps you think about what you mean when you say “stick to one side of the swamp.”
As always, the visualizer is available for you to try out:
https://macros.exfatloss.com/swamp
Until next time!
Exactly as I've been visualizing it all this time! Never got around to drawing it up so it's nice to actually see in writing.
My latest round of rapid weight loss was swamp taters also: potatoes + butter + chocolate, roughly even caloric split between carb and fat.
Planning another trial after I recover from surgery, and if it works a second time I'll do a write-up.
Fascinating as ever.
This is beginning to look a lot like an adaptation system to environmental food availability. Perhaps in our pursuit to avoid experiencing any negative feelings ever, we have optimised unavailability out of our diets - but our biology is built to run on EITHER fuel A or B, not both.
Perhaps crudely speaking we are awkwardly flip-flopping, burning inefficiently all the time as the machine never quite settles into one or the other.