The New York Times has launched a series titled, Scam or Not? A recent article in that series examined the ketogenic diet. Likewise, Julia Belluz, the excellent science reporter for Vox.com, published her recent assessment of research on ketogenic diets. A fair summary of both pieces might be, “yes there may be something here, but many claims are over-stated.” If you are considering a ketogenic diet or have had a mixed experience with keto-style eating, you may find these pieces insightful.
In this post I won’t review any research or re-invent their wheel; I’ll reason from basic principles, and try to give some perspective on keto-like diets based on my own experience.
I was successful losing weight on a keto-like diet. But ultimately I found this dieting style more useful as a transition than a destination. In this post I’ll more specifically expand on likely problems with a keto diet when pushed as a long-term style of eating. But as a short-term agency for weight loss, this post will, on net, endorse keto. Try it!
Overview
Briefly, keto-like diets take a broad-brush approach: 1) minimize your carbohydrates to way, way below the Federal advisory; 2) make fat the largest single component of your diet, say, 60, or 70%; 3) Don’t worry about anything else.
A typical keto-alteration of conventional meals would be, for breakfast, “keep the eggs and bacon, lose the orange juice, pancakes, potatoes and toast;” for lunch, “keep the turkey, swiss, tomato, lettuce and mayonnaise, lose the bread;” and for dinner, “keep the burger and cheese and avocado, lose the bun and the (loaded with sugar) BBQ sauce.” Skilled practitioners of keto find substitutes so that one doesn’t actually end up eating a naked burger, dinner after dinner; but the essence of the keto diet is to minimize carbohydrates, maximize fat, and let the rest take care of itself.
The goal from a weight loss standpoint is ketogenesis, where the body begins to consume its own reservoirs of stored fat, rather than relying for energy exclusively on continued quick-fix shots of carbohydrate, aka, the standard American diet (potatoes, bread, pasta, dessert).
Problems with keto
- Nutritionism
First principle: we eat food in the form of meals. We do not assemble carbohydrates, fat and protein in a beaker according to a percentage allocation and then pour them down a hopper.
I’ve elsewhere derided grazing for weight loss as the scientific equivalent of bloodletting to treat fevers. Here I want to challenge the carb / fat / protein model of diet composition. In a century or so, I expect scientists to regard this breakdown as neither more nor less scientific than the older notion that a healthy body must balance the humours corresponding to earth, air, fire and water. In short:
Fat, protein, carbohydrate ~ earth, air, fire, water
Really, do you believe that “carbohydrate” is a meaningful scientific term? Imagine a “History of White People in New England.” No insight into the contrasting experience of WASP capitalists versus French-Canadian and Irish immigrants could be expected from a pseudo-scientific concept such as “white people.” Likewise, imagine a book called “DNA of Brown People.” Few of us would expect to find scientific reasoning in its pages, despite the inclusion of a scientific-sounding term to lead the title.
I use these much more controversial and contested analogues to unfreeze your belief that “carbohydrate” is a meaningful way to speak about food. Decades of work have gone into exploding the notion that skin color corresponds to any meaningful genetic grouping. The same kind of deconstruction needs to be done in the field of nutrition.
Such nutritionism is particularly problematic in the case of carbohydrates, which in the US, for purpose of package labeling, are defined as “everything else”—anything which is not a fat, protein, vitamin or mineral otherwise called out on the label. Fat molecules are scientifically defined, as are protein molecules, by shape, structure and constituents; but carbohydrate means “none of the above.” In essence, keto diets demand that you minimize “Other;” and it is hard to believe that the “everything else” scorned under keto has a uniform effect on nutrition.
- Fiber
The attitude of the keto partisan is nicely summed up in this quote (from an MD in the Julia Belluz article): The “whole fiber thing is a myth.”
Think about it: an element found in almost every vegetable, seed or nut consumed by humans from time immemorial is here dismissed as irrelevant to nutrition. The emerging work on the micro-biome (showing that fiber feeds the bacteria in your gut) is dismissed out of hand.
But fiber is classified as a carbohydrate in the food label; therefore under keto, it has to be minimized. In fact, you can adhere faithfully to keto dietary prescriptions and never consume a single gram of fiber. Want to defend that position from the standpoint of long-term well-being?
- Whole grains
This challenge is a bit more ambiguous. Under my own keto-like weight loss program, I did minimize or eliminate any and all grains, whole or refined. For the weight loss portion of your diet, I confess, I don’t know what I believe. Maybe, during my initial weight loss program, I was smart to cut out all grains, brown rice as well as white rice, barley as well as wheat, yada yada.
But when the focus is on the longer term—and this is why I position keto-style diets as a transition not a destination—do you really want to cut out those super foods known as whole grains, forever after?
Are there no health benefits from whole grains, none at all, that can’t equally well be gained from brie and bacon, swiss and salami, steak and cheddar, eggs and sausage?
Thinkers. See below for a potentially helpful distinction between grain flour (the bane of weight loss) and whole grains (a member in good standing of any nutritious diet sustainable over the long term).
What keto gets right
- Keto gets you off sugar
The dietary experiment I would like to see would include a condition where the subjects ate as they normally did, except they attempted to eliminate all the added sugar from their diet and maintain that exclusion for at least a year. (Any juice would qualify as “added sugar”). I say attempted because sooner or later there will be a wedding cake or a holiday pie cooked by your aunt. Occasional lapses in the program are expected and become a co-variate in the experiment.
Keto diets more or less demand this exclusion of dessert; but most Americans, confronted with the bald program of “no sugar for a year,” would likely despair. Here the mythopoesis of keto comes into play as a motivational factor. Compare: are you simply to cut out sugar, to lose weight? Too boring and mundane to be sustainable, and maybe too slow. But turn your diet inside out with a radical alteration that privileges rather than disdains fat—that’s heroic enough to appeal to the heart. Advantage, keto.
But I predict the experiment would show that subjects in the no-sugar condition would achieve 25% to 50% of the weight loss seen in the pure keto condition. In other words, I assert that as much as half the weight loss on keto comes not from emphasizing fat, or minimizing “carbohydrates,” but from eliminating one kind of staple ingredient in the conventional American diet: added sugar.
But really: how many Americans could go cold turkey on sugar for a year? Merely reduce sugar? Sure, many people would step up to that plate; but reduction (from high levels) may only serve to slow weight gain, not produce actual weight loss. To have a meaningful impact on weight loss it has to be: “eliminate sugar.” And without the mythopoesis of keto, how you gonna motivate yourself to do it?
Not convinced about sugar? Repeat after me: “I can eat more sugar than any human ever did before 1600, when African slavery in the Caribbean made it possible to send a flood of cane sugar to the middle classes of the developed West; and while continuing to devour, every day, this unprecedented flood of sugar, I can also lose weight at the same time.” Really?
Crutch: I weaned myself off sugar by getting rid of everything except a square of dark chocolate after lunch. I recommend 85%+ cacao, and less than 2.5 square inches—call it two bites. That left me with added sugar under the salt threshold (2.6 grams / day). I lost weight that way; and I gained all the fiber and other benefits of chocolate.
It has to be 80%+ cacao, it has to be a single square, and it is best eaten before 2pm and with coffee and tea. Chocolate must not be a snack between meals and it must be much less than “serving size suggestion” on the package. Two bites.
- Keto gets you off refined grains
In a second cell in my hypothetical experiment, subjects would attempt to eliminate both sugar and any refined grain or starchy tuber. Ordinary Americans eat huge amounts of products made with grain flour (bread, pasta, and chips), plus refined grains (white rice), plus starchy tubers (potatoes). There would otherwise be no controls in this experimental condition, eat what you want, fat or no, just eliminate those two categories of food. I would predict that subjects in this dual condition would lose 50 – 75% as much weight as those in the pure keto condition. Long story short: any keto-like diet that gets you off sugar and refined grains will achieve a majority of the weight loss promised by the most severe and straitened version of the keto diet you can imagine.
The hypothesis here is that refined grains and starchy tubers are super foods—super at making glucose available to cells, thus making it unnecessary for the body to burn its own stored fat, thus making weight loss unlikely to occur. As a thought experiment, if you’ve had trouble losing weight, take your “net” carbs (carbohydrate grams minus fiber grams), divide by two, and add the result to your total sugar grams. For many Americans that total will be over 100 grams per day. How can you possibly lose weight if you are consuming over 100 grams of sugar-equivalents per day?
That’s the great gift of keto: for a spell, you are commanded to eat no grain flour and no potatoes.
Here the missing link in the conventional nutritional advice to “eat whole grains” becomes clear: flour, by definition, is not whole–it consists of grain that has been pulverized. Except for the few who eat brown rice, or steel cut oats, almost no American today eats any amount of whole grains on a daily basis. Whole wheat bread? Ha–if it wasn’t made that day by a local baker, it’s not … whole grain. It’s just wheat flour, more or less refined, a finely pulverized sugar-equivalent.*
*And there is some sentiment on the Internet that finely pulverized wheat flour—aka that staple you eat everyday—is absolutely the worst grain flour, from the specific standpoint of weight loss.
The grain of truth in keto’s broad-brush rejection of “carbohydrates” is the more specific requirement to eschew products made of flour, avoid refined grains, and stay away from starchy tubers.
But when phrased “scientifically,” as minimize carbohydrates, the baby gets thrown out with the bath water: you stop eating vegetables as well as refined grains and starchy tubers. Lotta carbs in carrots, you know.
Fresh vegetables are like fiber: some amount is good for you—don’t you think?
- Keto makes you question fruit
You know the dietician’s mantra: “for a healthy diet, eat plenty of fresh fruits and vegetables.” Fruits = vegetables, right? And fruit juice = fruit, right? Voila, I drank a glass of orange juice every day for 60 years, upgrading from Tang to Tropicana to fresh-squeezed, as my affluence increased. Ooh, those Odwalla banana-strawberry smoothies—so good for lunch! And fig newtons made with “whole wheat” and organic figs—mmm, good. It was fruit, how could it be bad for me?
As in 27 grams plus 27 grams plus 14 grams of sugar, plus another 12 from the fruit on my breakfast cereal. Even with no dessert, that was still 80 grams of sugar a day, for breakfast and lunch (maybe 100, after counting the granola). No wonder I added one pound a year, year after year, after I turned 30.
Keto makes you count carbs. Inspired by keto, the orange juice had to go. The granola had to go. All juice had to go. The organic fig newtons had to go. And my weight started to melt away, one or two pounds per month, month after mont.
But perhaps the same result could have been achieved from the simpler strategy: 1. No added sugar; 2. no grain flour or starchy tubers; 3. minimize fructose–especially, never drink it.
- Keto cures you of fat phobia
This may be the greatest keto benefit of all. Misguided public health efforts based on flawed research taught Americans that fat was bad—it’s gonna kill ya! Or as a male of my generation and class learned to say, about a keto-approved meal: “heart attack on a plate!” Instead, keto teaches that fat is good—for weight loss. And that’s very important.
Now here things get tangled, especially in the context of the controlled experiments that Julia Belluz has such a knack for summarizing. Imagine what I’ll call a naïve experimental design pitting a keto diet against a standard low-fat diet, with weight loss the outcome of interest.
The goal in any true experiment must be to control all extraneous factors and manipulate one thing only. If there is only one difference between conditions, then any difference in outcomes between conditions can be unambiguously attributed to that one difference. Do high fat diets produce more weight loss than low fat diets? To answer that question we must insure that the two diets across conditions are absolutely as identical as possible—except that one has high fat and the other low fat.
Therefore, if we are testing high-fat diets against low-fat diets, with weight loss the outcome of interest, we have to insure that subjects in both conditions—keto versus the low fat foil—consume exactly the same amount of calories, on the same number of eating occasions. But in so doing, alas, we control away the causal agent of interest. In fact, this calorie-equal experimental design destroys the key difference between keto and its foil, out in the world where people, you and me, live and dine; and then tests whether weight loss is any different in the absence of that key difference between keto and its foil. Doh!
Let me explain. Imagine the dual condition I described earlier: no sugar and no refined grains and no starchy tubers—three-quarters of the way to full keto. But everything else unspecified, eat what you want.
That permission doesn’t cut it if we are designing a typical experiment. We’ve got to somehow equalize the calorie consumption in the no sugar, no grain condition. Maybe, dinner in this condition has got to be a four-egg omelet heaped with cheese, accompanied by a chicken fried steak. Gotta keep those calories equal!
Oops, problem—what if fat were to be the most satiating of foods? What if the benefit of overcoming fat phobia were to be a lower need to consume calories, and a greater tolerance for long gaps between eating occasions? What if eating a two-egg omelet with two sausage links made it possible for you to skip the toast and potatoes and orange juice at breakfast, and be comfortable with the grilled chicken, parmesan and arugula salad for lunch—without the roll? Which in turn made you comfortable with the pistachio coated salmon fillet with prosciutto wrapped asparagus for dinner; which in turn made you feel full enough to skip any snack after dinner? Which then launched a mini-fast of 12 – 14 hours, before breakfast the next morning?
Under free-range conditions, eating that much fat, and cutting out that much sugar and flour, might lead to consuming hundreds fewer calories each day, net, without any subjective feelings of hunger, or a need to grab a snack. And all conventional wisdom believes that calories must be cut for weight to be lost. And Dr. Fung teaches that snacks are death to weight loss. But in a conventional experiment, we must systematically frustrate the natural tendency, when adequate amounts of fat are consumed, to want to eat less overall. The key benefit of keto—increased satiation despite fewer calories—gets undone. The effect of interest gets controlled away. The experiment forces participants in the keto condition to keep cramming it down. One key effect of keto—you eat less because satiated with less—gets controlled away.
- Keto may help your body to relearn how to digest fat—including the fat around your waist
Let me acknowledge first that this section is entirely speculative and has, as yet, no research support of which I am aware.
I’ll begin with an analogy. Vegetarians have told me that after some months on a vegetarian diet, if they do eat some meat by choice or chance, it sits heavy on their stomach, as if their body had lost the ability to readily digest animal protein.
Whether this subjective experience has any scientific backing I don’t know. The vegetarian’s sensation is easily dismissed as the discomfort that attends any departure from habit, or the uncertainty of whether a novel food is going to sit well (imagine first time sushi eaters: Gawd I just ate raw fish—does my stomach feel okay? Let me keep checking.)
But as ongoing scientific work develops the complexity of digestion, not least the role of the gut micro-biome, it is intuitive to suppose that if a vegetarian indeed has not consumed any animal protein for months and months, then the enzymes and gut bacteria that flourish in the stomach and intestines of a regular meat eater will simply not be present, or not present in inadequate amounts for the meal to feel “digestible,” or to “sit well.”
Now apply that analogy to fat. Americans with a history of dieting, or who have been attempting to eat healthy through food selection and rejection, will have spent years reducing or minimizing their consumption of dietary fat. It’s gospel: always choose the low fat or no fat option. Choose skim milk not regular. Choose no fat yogurt.
On the vegetarian analogy, these Americans may have lost their ability to readily digest fat. Whatever ability they initially had (which might vary by ethnic background) has atrophied. And here’s the leap: if you’ve lost much of the ability to digest fat in the diet, how readily can you move to ketogenesis, i.e., the digestion of the body’s own store of fat?
Of course, you can hope to kick start ketogenesis, and begin to lose weight, by intermittent fasting, without following the keto fat prescription. But maybe, you won’t be any more successful than a vegan trying to eat comfortably after a sudden switch to a herder diet composed exclusively of animal and dairy food.
The wisdom of keto as a transition diet, then, would be that it accustoms your body to getting the nutrition it needs from fat alone (since the easy, familiar route to getting energy, by consuming simple carbohydrates, has been shut down under keto). Your gut biome evolves accordingly; your liver, pancreas and gall bladder get retrained and re-accustomed to fat; under keto there’s no other source of energy other than the hard-to-digest fat that keeps coming at you meal after meal. You learn to deal with it.
Once the body has learned to digest fat in the diet, and gotten good at it, perhaps it also gets good at keto-genesis; in fact, maybe keto-genesis occurs every morning, while you are still asleep, provided that you follow the no-snacking rule, and maintain at least a 12 hour gap between dinner and breakfast.
Again, if you cut out all the cheap thrills—sugar, grain flour–gradually the excess weight melts away, starting with visceral fat. This process will speed up, the theory goes, if you give the body little else to eat other than fat. Soon the body learns to dip into its own fat stores, morning after morning, and also after any prolonged gap between meals.
Again, this one remains a speculative hypothesis.
What keto neglects
- The power of eliminating snacks
One weight loss study which Julia Belluz summarized imposed five eating occasions per day—for weight loss! Experimental design overwhelmed common sense. Three meals and two snacks per day have become the American norm; and in search of ecological validity, the experiment mimicked those real world conditions. But no sane person would expect to lose weight by continuing to eat three meals and two snacks per day.
You cannot lose weight if the body is never left to its own devices. You will not consume the fat around your middle if you eat a snack at the first pangs of hunger, all day and every day. The body won’t eat into its stored fat unless there is no alternative. Snacking is the constant provision of alternatives to ketogenesis, strangling it in the cradle.
- The power of intermittent fasting
If ketogenesis is the goal, why change what you eat? Instead, perhaps you should just … stop eating. The body knows what to do when there is nothing incoming. And that’s part of the power of eliminating snacks: you “stop eating” every day, or every night rather. Trust me, if you have dinner at 6:00 pm and do not have breakfast until 8:00, every day; and you eat no sugar or grain flour, and you never snack, you will begin to lose weight.
But then again, can you stop snacking without the aid of a keto transition? That may be the true power of keto: it helps the body get better at going without food and then turning to its stores of fat, readily, easily, regularly consuming its own.
But once that transition has been executed, keto becomes a partial, slanted diet, difficult to support as an ongoing program.
Summary
Learn from keto. Get rid of the sugar, and drastically reduce or eliminate grain flour from your diet, especially finely pulverized wheat flour. And lose your fat phobia.
But don’t suppose that fat itself causes weight loss. And don’t expect snacks made of fat will do you any good—the goal is no snacking at all, achievable because you ate enough fat in your meals to make you sated enough not to snack.
To finish, here is a modification of a famous diet haiku:
No sugar
Not much grain
Never snack
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