Evaluating diets: why most don't work, for most people, most of the time

Even a broken diet can be right 2x per day

There are a whole lot of diets out there, and some of them work, for some people, some of the time. Most of them don’t work, for most people, most of the time.

How can this be?

The obvious answer seems to be that they are somewhat orthogonal to “what actually works” but accidentally hit some of the buttons, some of the time.

Sometimes, they use a heuristic that’s not relevant, but leads some people to do the right thing, and others to do the wrong thing.

Other times, the diets do one thing right, but other things wrong: these work for people whose only problem was the one thing this diet fixes.

False Positives

A false positive would be something the diet allows, but which actually prevents fat loss. Presumably, the diet leaves this open to interpretation and doesn’t mandate it, or nobody would have success on the diet.

Or it’s only a false positive for certain people, and so it’ll work for say 30% of obese people, but not for the rest.

An example would be polyunsaturated fat or high protein on a Standard American Keto diet. The recommendations stipulate you eat a lot of fat, but not technically against PUFAs. Most ketoers won’t exactly recommend you chug soybean oil, but they do recommend a lot of foods that are very high in linoleic acid, like commercial bacon or nuts.

This means that people who happen to like bacon and nuts will consume a lot of linoleic acid, whereas people who naturally don’t like those foods will avoid them.

The efficacy of SAK can therefore depend on your food preferences, and if you accidentally travel the “correct” path across the wide-open keto space.

False Negatives

False negatives are the opposite: the diet prohibits you from eating something which is not causal in your obesity. This might or might not be a problem.

In a not-so-bad case, say you’re keto and it prohibits you from eating bread. Maybe you never liked bread, anyway. Maybe you’ll miss pizza, but that’s about it.

On the other hand, it could hit you real hard: if the diet prohibits most of your favorite foods unnecessarily, it is unlikely you’ll do it, even if it would otherwise be efficacious.

This is a limiting factor for keto and carnivore. There’s a certain percentage of the population that is willing to give up carbs forever, but it’s probably no bigger than 15-30%. That means that 70-85% of people will never seriously do keto or carnivore, even if it was the only effective way to lose weight.

Luckily for those people, I don’t think it is.

Still, you can see how a diet with excessive false negatives would be harder to stick to, unless the foods that are allowed happen to exactly be your favorites - as mostly happened with me and keto when I started it.

Pretty much the only foods I ever missed were pizza, once my favorite food, and - lentils. The lentil thing is a bit weird, and I’ve never cheated with lentils once, I think. I just love the stew-like consistency.

Apart from that, I could still eat almost all of my favorite foods: meat, dark chocolate, cocoa, nuts, cream, cheese, grilled chicken, bacon & eggs.. keto has a lot of false negatives (I think), but they barely affected me.

Concrete diet examples

Let’s analyze some diets in more detail so we can have concrete examples.

For this post let us stipulate that obesity is caused by these factors:

1. Excess linoleic acid in food intake & adipose tissue

2. Inability to switch efficiently between BCAA, glucose & fat metabolism (likely caused by 1.)

This post isn’t about this particular set of hypotheses, even though it is what I believe to be true. But let’s just use these to compare which diets have which false positives & negatives, to illustrate the concept.

If these are the factors that cause obesity, what would the optimal diet recommend to reverse obesity?

1. Cut out linoleic acid intake as much as possible

2. Severely limit at least 1, but likely 2 of {protein,carbs,fat}. You probably want to pick 1 of the energy macros (carbs/fat). You’ll likely also need to restrict protein to a certain degree. In short, don’t “swamp” your macros.

Ok, now that we’ve assumed this to be the optimal diet (for comparison purposes), let’s dive into some popular diets out there and see how they do.

Vegetarianism / Veganism

The heuristics here are “no dead animals” or “no animal products at all.” Suffice it to say, both of these are completely orthogonal to our causal factors.

Linoleic acid is originally a plant product, but it is present in many animal products - monogastric animals fed a high corn/soybean diet, like commercial pork and chicken.

The second causal factor, “no swamping,” is technically not implied at all by either heuristic, but in practice, most vegetarians or vegans will likely restrict fat, and many protein.

While you can get lots of fat from plant sources, cultural limitations and “that’s how we’ve always done it” seem to lead most vegetarians/vegans to a low-fat, low-protein diet.

This isn’t always true: when I was vegetarian, I ate mostly dairy products. I love dairy, and it’s much more energy dense than most plant products, so I didn’t have to stuff my face with all those annoying grains & vegetables. Of course, I didn’t lose much if any weight this way.

Whole-food plant based

I’m never quite sure if WFPB is just a vegan marketing ploy, trying to get you to be vegan without giving away the end goal.

But the “whole-food” part does quite a bit toward our causal goals here, because seed oils are not a whole food.

The simple rule of cutting seed oils and processed food (which contains seed oils) out of course does much more work than “is it animal based?”

But the “no dead animals” rule cuts out most of the atrocious linoleic acid sources that you can get from animal sources, such as chicken and bacon.

Pretty much the worst thing you can eat on WFPB is nuts, which are high in linoleic acid despite being “whole.” But unless you happen to binge on nuts all the time, chances are that you’ll drastically lower your linoleic acid intake.

The culture and common canon of WFPB is also both low-fat and low-protein, meaning that if you just follow their main gurus, you’ll be good on that front.

Seems like a pretty good deal: WFPB gets a lot more things right than the more morally oriented “is it an animal product?” rule.

Still, there are quite a few false negatives: it cuts out all beef, lamb, and dairy, many of which are great and not at all at the root of obesity.

It also seems like long-term vegans/WFPB people become very skinny and sarcopenic to an unhealthy degree. I don’t know if this is because they restrict protein for way too long. But it’s something I’d watch out for if I was to pursue this diet.

Low-carb / Standard American Keto

Oh boy, this is my favorite! What I call Standard American Keto is how I gained 100lbs after first losing it.

What is Standard American Keto? It’s not a real “classic ketogenic diet” but what you’d find being recommended for fitness/lifestyle fat loss purposes by popular keto diet gurus.

It’s much higher in protein than a real ketogenic diet, and it’s also typically high in bacon, and often nuts. While most keto gurus probably wouldn’t tell you to use seed oils, linoleic acid is rarely on their radar, and any critique of ad-lib daily bacon & chicken is perceived as vegan propaganda.

This diet avoids most literal seed oils if you cook at home, I’ve yet to meet a ketoer who cooks in seed oils.

But it quickly falls apart at restaurants. I mostly ate the chicken salads when I went to restaurants, and the dressings are all based on soybean oil.

These diets also often encourage nuts, which are high in fat, mostly polyunsaturated except macadamia. Nuts & cheese was my go to snack at the office when on SAK, and it made me ravenous.

The SAK is also improbably high in the animal-based sources of linoleic acid: bacon is celebrated, as is roasted chicken, especially the fatty parts.

For our second causal factor: by definition, a keto diet is very low in carbs, so they’re restricting 1 macro. That’s likely the reason why keto works so well for maybe 15-30% of people. They just needed to restrict any 1 macro, and their metabolism was fixed, or at least in remission if they were jacked up on linoleic acid.

But for the people who need to restrict 2 macros, like myself, this “fitness oriented” high-protein version of keto is terrible news, and can often even lead to weight gain, or just weight stalls.

These people will usually aggressively denounce anyone promoting a low-protein diet as vegan propaganda. I got banned from r/keto for just mentioning that I was doing low-protein. (I am unbanned, apparently! Maybe it expires after a year?)

Carnivore

Carnivore fares significantly better than Standard American Keto, which is likely why it works for a number of people for whom regular keto didn’t work. It’s also much simpler to explain, and simplicity is a huge benefit: it reduces potential for error, but it also reduces mental overhead for those new to the diet.

What does carnivore exclude that SAK allows? Nuts, salads & dressings at restaurants. Depending on the sort of carnivore you do (there is no One Official definition) it also excludes dairy, and cheese especially seems ultra obesogenic even among high-protein foods.

The downside is a much larger number of false negatives: it disallows pretty much everything except meat/maybe eggs/very maybe dairy, depending on which variant you choose.

Interestingly, there’s also a cultural trend where most U.S. carnivores mainly choose beef. This isn’t usually canon, and exceptions are made, but it’s very common to hear (U.S.) carnivores say that they “feel best on beef,” and most long-term carnivores choose beef as their primary meat.

Still, a lot of carnivores post daily pictures of their bacon breakfast, and their eggs cooked in bacon grease. Roast chicken is also not uncommon. So it really depends on your own interpretation of “carnivore” if you’ll get the linoleic acid part very right or very wrong.

The swamping part is almost impossible to get right. Of course you’ll get almost 0 carbs, since you can only eat animal products, and most versions of carnivore don’t allow dairy, which is the major animal source of carbs (lactose).

But it is also both highly encouraged to eat high protein on carnivore, and, in practice, nearly impossible to avoid.

Even if you only eat fatty ground beef (say 80% lean / 20% fat) and ribeye steaks with slices of butter, you’ll be eating an extremely high protein diet by any measure.

To get 3,000kcal/day from ribeye steaks, the TDEE of pretty much any adult man, you’d need to eat 2-4lbs of ribeye, depending on the fat content. That means you’re getting 200-500g of protein, by far more than anybody needs.

You can add butter to every steak, which I did when I tried carnivore for 90 days - but that’ll merely turn it from a bizarrely-high-protein diet into a super-high-protein diet.

A single pound of fatty beef contains roughly 80-100g of protein, which is way too much for any sort of protein restriction.

And if you restrict yourself to, say, half a pound of beef per day, where are you going to get the remaining 2,500kcal from? Butter, beef tallow, heavy cream (if allowed)?

There’s a sub-category of carnivore called Keto AF, coined by Amber O’Hearn. Her website is aptly named “mostly fat” and it promotes a carnivore variant of only beef, mostly consisting of the beef fat with only an adequate amount of lean meat.

But while the “whoa, I get to eat all the steak & bacon I want?!” of Standard American Carnivore might sound great to maybe 20-30% of the population, the “you can’t even eat a whole steak, and most of your food will be beef trimmings” version is much less “lion” and manly sounding.

My own diet ex150 is sort of a version of Keto AF: in trying Amber’s version, I couldn’t stomach all the beef fat, so I substituted heavy cream instead. I tolerate dairy exceptionally well, much better than the beef fat. I’m also not totally avoiding plants, but I use them as seasoning/for flavor, typically limiting them to 60g of green vegetables & 80g of tomato sauce per day, mostly to soak up the excess beef fat and butter from cooking.

Both Keto AF and ex150 get both our causal factors right, but they’re also both extremely limiting. You’re not just down to “animal products,” you’re down to literally 3-4 different types of foods that are allowed: beef, beef fat, butter(, heavy cream).

Paleo

Paleo was huge when I was in college, and I followed it for a long time. Unfortunately, while it put the extreme acid reflux I developed in my early 20s into remission, I never lost any weight on it.

There are various different types of Paleo described by the various gurus like Mark Sisson (“Primal”), Robb Wolf, and others.

I seem to remember one definition from then going something like this:

Eat lean meats, fruits & vegetables, nuts & seeds.

Unfortunately, this is almost entirely wrong by our 2 causal criteria. Let’s break it down:

• Lean meat: great advice for monogastric animals (pork/chicken), terrible advice for beef and other ruminants. Unnecessarily avoids a lot of ruminant fat, which is a cornerstone of pretty much any healthy diet.

• Fruits: fine if you’re going High Carb, Low Fat, Low Protein, bad otherwise.

• Vegetables: mostly orthogonal for green/non-starchy vegetables, starchy vegetables same as fruit.

• Nuts & seeds: terrible except for macadamias, since most nuts & seeds are chock-full of linoleic acid.

Paleo was very popular with CrossFitters at the time, and as a budding guy in my 20s I obviously did & followed CrossFit. I remember videos of Chris Spealler, a prominent CrossFit “Fire Breather” and one-time “100 pull-ups in a row” performer, going into Whole Foods to buy & eat almond butter with a spoon.

Suffice to say, I think that Paleo is pretty terrible in retrospect. It steers us away from ruminant fat, one of the best sources of energy available.

Another big downside is that Paleo pretty much prevents dairy. For me personally, dairy is the ultimate superfood. I’ve never lost weight without a significant part of dairy fat in my diet. Like ruminant fat, it is the ultimate inert energy source, and unlike ruminant fat, I can digest near-infinite amounts of it.

When it comes to our second rule, “no swamping,” Paleo doesn’t explicitly say, but pretty much prevents you from doing this correctly. “Lean meats” are usually high-protein meats. You could, of course, eat an extremely small meal of lean meat to restrict your protein, but nobody on Paleo has likely ever done this.

You also can’t really pick between energy and carbs on Paleo, unless you turn it into the potato diet or something. Nuts & seeds are very fatty, and even “lean meats” are probably not entirely chicken breast.

Any version that fulfilled our 2 causal rules would be such an extreme and bizarre version of Paleo that nobody would recognize it as such.

Mediterranean Diet

Now we’re getting into diets I haven’t tried personally, but I wanted to include some others just for reference.

The Mediterranean Diet was infamously invented by an American on vacation, and nobody in the Mediterranean has ever eaten it. It’s a fun hobby of mine to watch Spaniards, Italians, Greeks, and other natives of the Mediterranean react to this diet in wonder.

To quote Wikipedia:

This approach [the Mediterranean Diet] emphasizes a plant-based diet, focusing on unprocessed cereals, legumes, vegetables, and fruits. It also includes moderate consumption of fish, dairy products (mostly cheese and yogurt), and a low amount of red meat.

I’ve spent a number of vacations in Spain, Italy, and Greece, and I can tell you that I haven’t had a single cereal or legume in any of those countries. I suppose paella and risotto have rice, but they use white rice.

Vegetables are served, but as sides to the main dish - red meat. These people eat more pork than all of Congress combined, and they eat so much fatty cheese that even I had to wave the white flag. Oh, and they just straight up eat animal fat as a delicacy.

Beef is a bit more rare there, but just because it’s expensive. The Italians absolutely have steak dishes like Bistecca alla Fiorentina and they love veal.

Overall, I don’t think you would have as easy a time as a vegan in any of these countries as you would in the U.S. People would likely laugh at you if you declared you don’t eat animal products.

Do they eat fish? Sure. But they eat way more meat than fish even on the coasts.

“Where’s the lardo?” wonders the Italian.

Lardo. If the word sounds familiar…

“Where’s the Jamon Iberico?” asks the Spaniard.

Jamon Iberico

“Where’s the gyros?” cries the Greek.

Gyros. You can tell how lean it is by the thick, glistening shine.

That said, how does the Mediterranean Diet, as envisioned by Wikipedia/Ancel Keys, fare against our 2 criteria of obesity?

It actually does pretty well, if you go by the book. The Mediterranean Diet is basically a watered-down whole-foods, plant-based diet, allowing for some fish, some red meat, and some dairy.

That means there’s going to be little linoleic acid from animal products, and it’s also not exactly encouraging you to cook in seed oils.

On the other hand, from what I’ve seen, the fear of saturated fat is so overwhelming that they end up defaulting to seed oils, at least over butter or other animal fat sources.

Olive oil is the end-all, be-all for Mediterranean Diet types, but since 50-80% of all olive oil world wide is adulterated with seed oils, and even genuine olive oil is 8-20% linoleic acid depending on the olives used & the processing, it’s a bit less than optimal.

Still, it’s likely going to be much better than the Standard American Diet, or even - gasp! - many variants of Standard American Keto.

On the swamping front, both fat and protein are somewhat discouraged. There isn’t much fat or protein in “unprocessed cereals, legumes, vegetables, and fruits” and so you’ll have to get the entirety of your fat, and the majority of your protein, from the “also ran” group.

Overall, the Med does quite well on the swamping front. If you actually chose olive oil, or no oil, or ignored that part and just used butter, you’d likely fare quite well on it.

This is pretty ironic, given that the main goal of the Mediterranean Diet is to avoid saturated fat - which isn’t implicated at all in obesity.

DASH diet

DASH is a silly acronym for a bureaucrat “health” diet that I’ve never seen an actual person do, ever.

The DASH diet is rich in fruits, vegetables, whole grains, and low-fat dairy foods. It includes meat, fish, poultry, nuts, and beans, and is limited in sugar-sweetened foods and beverages, red meat, and added fats.

So it’s basically the exact same as the Mediterranean Diet. I don’t even know why they bothered making an acronym. Are grains the same as cereals?

Interestingly:

2–3 servings of fats and oils

And they’re discouraging saturated fats. So unless you had access to the 20% of non-adulterated olive oil, and used that exclusively, they’re recommending you consume 2-3 servings of seed oils per day. I suppose you could eat a whole avocado instead, too.

Still, precarious: the entire balance for our causal factor #1 depends on how you interpret/act on this one line.

Overall, the DASH diet is a carbon copy of the Med and therefore scores similarly. Except it’s less sympathetic.

(Seriously, I’ve never, ever met anyone who’s tried it.)

Zone diet

The Zone diet was very popular with the CrossFit crowd before Paleo kind of took over. Many tried to combine the two approaches.

The Zone diet is based on a book of mostly junk “science” and has pretty much exactly 1 principle: you need to keep your macronutrient distribution in a certain “zone” and that zone is: 40% carbs, 30% fats, 30% protein. As a secondary factor, it recommends low-glycemic index carbs and MUFAs over other fats.

There was a huge debate when CrossFitters abandoned the Zone diet and migrated to Paleo, and I remember one funny interview: a famous CrossFitter interviewed Barry Sears, the inventor of the Zone diet, and asked him a hypothetical question: would it be healthier to eat a Twinkie-style diet with Zone macros, or a Paleo-style diet of whole foods, but with a “wrong” macro distribution?

Sears enthusiastically recommended the “Zone-balanced” Twinkie diet.

I haven’t heard anyone mention the Zone diet in over a decade, and it seems they now mostly sell diet candy bars, similar to Atkins. Honestly, the ingredients on those candy bars aren’t even particularly bad compared to others.

But let’s evaluate the zone: it’s almost entirely orthogonal to linoleic acid, although apparently MUFAs are preferred, but I couldn’t tell if to SFAs or to PUFAs. And it mandates swamping as its Prime Directive.

Overall, I don’t think there’s much behind the Zone diet. You might accidentally be successful if you avoided PUFAs on it and you were ok with heavy swamping, which few obese people are.

Volumetrics diet

This has got to be the dumbest idea I’ve ever heard.

It’s all about volume; lose weight by filling up on low-calorie, nutrient-dense foods

You know what has nutrients in it? CALORIES! All the macronutrients are full of cArOliEs. So a diet can - by definition - not be low-cAloRiE and nutrient-dense at the same time.

I got news for ya: just eat sawdust & cardboard. Heck, why eat? Just fast!

My own dietary approach is the literal opposite of this: heavy cream is the least calorie dense meal I eat. Why would you fill yourself with largely non-foods? Your body’s not that stupid, it won’t “stop being hungry” just because you bloat yourself up like a balloon. This is easy enough to try, eat exclusively non-caloric foods like salad and you’ll know what I’m talking about.

You could actually have success on this diet, but it would be a mere coincidence: like “is it an animal product?” the volume or energy density of a food is entirely orthogonal to both linoleic acid and swamping.

Accidental Success

As you can see, many of these diets will lead many people to accidental success. The heuristics they used often had almost nothing to do with their success factors, it was the luck of the draw (they didn’t require something their heuristic didn’t cover) or they intuitively preferred a sub-variant that, while not specified by the diet, happened to solve their problems.

HCLFLP is all the rage on r/SaturatedFat right now, and it’s basically WFPB + lean beef. Many people there read all the vegan books, discard the propaganda, and just skip straight to the recipe section.

All the low-fat diets are fine if you avoid linoleic acid. They tend to be low-protein as well, if not per prescription, because people who like low-fat are vegans and vegans hate protein.

The high-fat diets are actually more dangerous, I think: if you eat 80% fat, you only need to get a few things wrong to massively overconsume linoleic acid. Making bacon or other fatty pork a staple is enough. Eating restaurant salad dressing a few times a week is enough. Nuts.

And people who like high-fat diets also tend to love protein, so while they might be restricting carbs, almost all of them will be swamping fat + protein.

As Simple as Possible, but not Simpler

Simplicity is a virtue. If you have to explain a diet by starting at biochemistry and reminding your interlocutor of what double bonds are, and how redox balance works in the mitochondria, there might just be a slight apprehension to trying your diet.

On the other hand, not everything can be simplified further. Eventually, simplifying a signal will induce loss - think of old low quality music files, if you’re old enough. To save on disk space, these compressed the audio too much. This caused them to lose important information and the music sounded terrible. Many modern music files are lossless, meaning they only compress enough to save space, but stop just short of losing audible information.

Diets are a bit like this. I could give you a one-word diet description, but it likely wouldn’t capture the entirety of the concepts.

• plant-based (allows seed oils, huge false negative rate)

• animal-based (allows bacon/chicken, huge false negative rate)

• low-fat (doesn’t specify which fat, technically allows high-protein swamping)

• low-carb/keto (doesn’t specify which fat, likely high-protein out of necessity)

The best answer isn’t nearly as simple. For one, you’ll have to understand what fatty acids are, and PUFAs, and linoleic acid, and how the food chain works (soybean/corn → animals) and what monogastric vs. ruminant animals are, and you probably need to understand why swamping is a problem, which involves the TCA/Krebs cycle and distinguishing individual amino acids..

But then, hopefully, if your 2 causal factors are indeed necessary & sufficient, you can create the optimal diet: no false negatives, and no false positives. This should ensure success, but also prevent you from cutting out anything you don’t need to cut out, making dietary choice much wider and more sustainable for many people who e.g. couldn’t stick to carnivore or just potatoes for the rest of their lives.

In a sense, we just need to eat the refined, processed food our grandparents ate - but take the linoleic acid out of the food supply.

Maybe we’ll find out that these 2 are not enough, and then the “real” optimal diet will become even more complex.

But I’ll take efficacy over simplicity any time.