Why keto is here for keeps – and how to get started on a low-carb, high-fat lifestyle
High-fat, low-carb eating remains controversial. But for some people, a new book argues, it just works
By Tom Ough
Back in 2002, the science writer Gary Taubes was, to much of the medical establishment, a pariah. Taubes had authored an article for The New York Times Magazine called “What If It’s All Been a Big Fat Lie?”
From the piece’s beginning to its end, Taubes cast doubt on the medical orthodoxy that low-fat diets were helpful for weight loss. Low-fat diets, he said, were likely to be partially responsible for America’s ballooning obesity crisis (mirrored here in Britain). The evidence was beginning to indicate, Taubes wrote, that a diet low in carbs and high in fat, however – eggs, bacon, butter and so on – would, counter-intuitively, make its eaters slimmer and longer-lived.
At that point, the most prominent guise of the low-carb, high-fat (LCHF) regime was the Atkins diet. Robert Atkins, whose books on the topic sold millions, was seen by the medical establishment as a peddler of a fad diet that encouraged the consumption of dangerous quantities of fat and protein. On publication of his article, Taubes acquired a similar reputation.
But look at the new arrivals in any bookshop’s food section. Look at the diets being discussed online. Listen to how your friends and relatives are aiming to lose weight. You will read and hear the word “keto” repeatedly.
“Keto” is short for “ketogenic”, a word that refers to ketosis, the bodily state in which you use fat for fuel instead of carbohydrates. The keto diet, which is essentially the Atkins diet shorn of the name of the doctor, who died in 2003, has become more mainstream than ever, and Taubes remains at the vanguard. His new book, The Case for Keto, argues that those who fatten easily – and Taubes includes himself – should spurn carbohydrates, whose consumption results in the release of insulin, a hormone that prompts our bodies to store energy as fat. These people should replace carbs with dietary fat, which doesn’t spike insulin. When our insulin levels are low, our bodies are primed to burn adipose fat for fuel instead of adding to it.
“A few tens of thousands of physicians are now prescribing these diets,” says Taubes, speaking via webcam from his home in Oakland, California. “That’s all from, say, a dozen 20 years ago.” He says there are about 100 scientific trials of ketogenic diets being conducted in the United States. “The research community has gotten fascinated by them because they’re so effective.”
Taubes has experienced this effectiveness. Around the time that he began researching his controversial article, he weighed 17st 3lbs, an increase of 2st 3lb from his weight as a young man. “I hadn’t had an avocado in a decade. I thought that, like red meat, it would kill me with heart disease or colon cancer the moment I bit into it.”
Intrigued by what was then the fringe science of low-carb, high-fat, he experimented with the Atkins diet. “I switched from this low-fat, mostly-plant diet on which I’d been getting fatter. I started eating eggs and bacon for breakfast, and lunch would be half a roast chicken or a steak with green vegetables.” Dinner would be similar. Taubes lost 11.3kg (almost two stone).
Today he is a lean and muscular 64-year-old. Taubes is a good advertisement for the keto diet, to which he remains faithful. He is still fighting the dogma that obesity is a consequence of individual weakness rather than a hormonal imbalance caused by the modern Western diet. Our bodies, the argument goes, evolved in an environment where fatty meats and fresh leaves were much easier to come by than the starchy, sugary foods we eat today.
Yet public health guidance typically recommends bread, pasta and potatoes. “Starchy food,” says the NHS’s Eatwell Guide, “should make up just over a third of the food we eat.” Guidance along those lines, Taubes says, “is just the wrong advice. It works for lean and healthy people, who, if they follow that advice, will probably remain lean and healthy. But for those of us who are predisposed to get fat, and we are now 50 per cent of the population, that’s the wrong advice. We do that diet and we get fatter, and/or we get hungry. So we’re either going to be fatter, and trying to restrict how much we want to eat all the time, because we’re constantly hungry, or we’re going to eat to satiety and really have a problem with our weight and our blood sugar.”
So why would the NHS and other public health authorities promulgate such a destructive diet? Advocates of low-carb, high-fat argue that this has happened for several reasons. The main one is that people of naturally healthy weights tend to assume that whatever they eat should work for others, too. So in a society in which most people are slim and grain-based diets are cheap and practical, grain-based diets are likely to appear favourable. Based on what was, in Taubes’ view, flimsy evidence, nutritionists such as the charismatic Ancel Keys argued from the 1950s onwards that saturated fat caused heart disease. Food manufacturers used cheap, high-carb products such as corn and wheat, using them to create processed foods that were marketed as low-fat but which exacerbated obesity rather than alleviating it.
Since then, as Taubes has argued, the medical establishment, seeking to first, do no harm, and educated to believe that saturated fats cause heart disease and strokes, has stuck to the default option of supporting the status quo: a high-carb and often highly-processed diet that has pushed hundreds of millions of people into obesity and now keeps them there at terrible medical and psychological cost. As most overweight dieters discover, their bodies have become primed to crave food and to vigilantly store it as fat. Eating a conventional Western diet, they have as much chance of not getting fatter as a child has of not getting taller.
This is a far harder game than calories-in versus calories-out, or indeed the “eat less, move more” mantra offered by the Government. Doesn’t it make Taubes angry? “Atkins got angry when he wrote his first book. He let his anger show, and he thought the conventional wisdom was ridiculous, and he got crucified for it. My editor [of his first book on food, Good Calories, Bad Calories] kept taking out my anger and my sarcasm, saying ‘Take the high road, take the high road. Just state the facts and don’t let it get to you.’ As I got attacked for the things I was writing, part of the learning experience is learning not to get angry.”
Keto is still seen as a fad diet, but it is probably more akin to what our prehistoric ancestors ate than a high-carb diet. Atkins was one of a long line of advocates of low-carb, his notable predecessors including William Banting, a Victorian undertaker who beseeched his peers to follow his example in losing 3st 7lb by giving up starches, and Jean Anthelme Brillat-Savarin, a French lawyer and politician who wrote in 1825, as Taubes notes in his book, that grains and starches are fattening and sugar makes it worse.
So what are the objections? Some trials have not found that keto is any more helpful for weight loss than other diets, though such is the complexity and variation of human nutrition that it is hard to find unanimity on any intervention.
There is little research on the diet’s long-term effects (though Taubes would point out that the long-term effects of a Western diet can be pretty atrocious). Famously, diets of the ketogenic variety – eggs and bacon, steaks etc – are associated with high cholesterol, in the form of low-density lipoproteins, and heart disease. Taubes refers to studies including one that was completed at Indiana University in 2019 and that showed that two years of ketogenic eating decreased participants’ risk of having a heart attack “by over 20 per cent, compared to the usual treatment programme for diabetes and all the drug therapies typically prescribed. Even with the rise in their LDL cholesterol, these patients got significantly healthier, as did their hearts.”
It may be that some people’s physiologies benefit from low-cholesterol diets, says Taubes, but that is not enough for it to be worthwhile for an overweight person, who is in a constant low-level state of inflammation and who is at a higher-than-average risk of cancer, heart disease and, of course, Covid, to stick to the high-carb diet that put them there. “Ninety-nine out of one hundred of us who avoid butter and bacon for a lifetime,” he writes, “may well do it for no health benefit whatsoever, even if the conventional wisdom on saturated fat is right.”
Other critics include those concerned by the environmental cost of eating lots of animal products; vegetarian and vegan ketogenic diets are possible, but difficult. Some low-level dissent even comes from within his home, where Taubes’ wife and children keep a drawer full of crisps and pretzels. “I wonder how many marriages this keto thing has ruined,” he says wryly. But he will stick to his butter and bacon, his avocados and his olive oil. Ketogenic diets remain controversial, and there may be other important factors behind the obesity crisis. Other mooted culprits include the addictive nature of processed food; snacking; eating within too large a window of time each day; imbalance between omega-6 fats (found in vegetable oils and nuts) and omega-3 fats (found in oily fish, coconut oil, butter and so on); and even central heating.
Even within this range of options, ketogenic diets are viewed increasingly widely as an escape route from the problem. And given our society’s profound issue with obesity, perhaps the truly extremist position is not Taubes’s, but the status quo.
Interview by Tom Ough. Extracts below taken from Gary Taubes, The Case for Keto (Granta) © Gary Taubes 2020
How to begin a keto diet
What to eat, what not to eat, and how to plan it
Carbohydrate-rich foods are fattening. Or to complicate it slightly such that naturally lean people might be more likely to understand: For those of us who fatten and particularly those who fatten easily, it’s the carbohydrates that we eat – the quantity and the quality – that are responsible. The relevant mechanism appears to be simple, as well: Carbohydrate-rich foods – grains, starchy vegetables, and sugars – work to keep insulin elevated in our circulation, and that traps the fat we eat in our fat cells and inhibits the use of that fat for fuel.
The only way to eat a satiating meal while minimising insulin secretion is to add fat. It’s the one macronutrient that does not stimulate an insulin response.
Abstaining from carbohydrates and carbohydrate-rich foods means you won’t be eating the foods in the list below. You won’t be eating them because they are predominantly carbohydrate and so will raise your blood sugar, stimulate insulin, and promote fat accumulation and hunger.
- No grains, which means no rice, wheat, corn, or even “old world” grains like quinoa, millet, barley, and buckwheat. No products made from these grains: no pasta, breads, bagels, cereals. No sauces that use cornstarch as a thickening agent, as many do.
- No starchy vegetables, so no root vegetables or tubers. No potatoes, sweet potatoes, parsnips, or carrots. You won’t eat vegetables that grow below ground. It’s OK to eat those that grow above ground.
- No fruit, with the exception of avocados, olives, and tomatoes (all technically fruit), and with the possible exception of berries.
- No beans or legumes, which means no peas, lentils, chickpeas, or soybeans.
- Absolutely no sugary foods and particularly sugary beverages, even if the sugar comes from “natural” sources like fruit: so no soda, fruit juice, smoothies, cakes, ice cream, candy, bonbons, or even health-food bars, and perhaps particularly those advertised as low in fat.
- No milk or sweetened yogurts, particularly low-fat varieties (in which the fat content is removed and replaced, typically, with some kind of sugar). I agree with Michael Pollan, the author of In Defence of Food, that if a food product makes a health claim on its packaging, it’s probably a good idea to avoid it.
In general, the more fibre a food or food product contains and the greater the proportion of calories from fat, the lower the blood sugar response, the lower the insulin response, and the more benign this food might be. Research suggests that we have huge individual variation in how our blood sugar responds to different foods, which implies a huge variation in insulin as well. Maybe potatoes are benign for some, but not others. The problem is we don’t know, and if we did, “more benign” might not be good enough. So the best advice, if we’re committing to being healthy and ideally lean, is to abstain from all.
Those who succeed are those who come to think of abstaining from carbohydrate-rich foods as critically important to their health, in the same way that ex-smokers consider continued abstinence from cigarettes vitally important and members of Alcoholics Anonymous consider the act of abstaining from drinking. This means you will have to figure out how to avoid temptation in a world that will serve it up.
Foods that you can eat
These are foods that are very low in carbohydrates and/or high in fats. You can cook these foods any way you like (baking, grilling, stir-frying, roasting), but you have to avoid using flour, breading, or cornmeal in the preparations.
- Meat: from animals or fowl (chicken, turkey, duck, goose), the fatter the better and all preferably raised on grass, in pastures, and not in factory farming conditions
- Fish and shellfish
You can also eat:
- Butter, preferably from grass-fed animals, and oils, preferably from fruits rather than nuts, seeds, or legumes, and so olive, coconut, or avocado oil
- Low-carbohydrate vegetables, which means all leafy green vegetables, in particular, kale, spinach, and lettuce, but also cabbage, broccoli, cauliflower, asparagus, brussels sprouts, tomatoes (technically, a fruit, as mentioned), mushrooms, cucumbers, zucchini, peppers, and onions
- Fatty fruits: olives and avocados
- Dairy fats: cheeses, cream, (unsweetened) yogurts, all full fat
These foods you can eat but in moderation:
- Low-sugar chocolates, the lower the better
- Nuts and nut butters
- Seeds and seed butters
“In moderation” because they fall on the borderline of acceptability: Clinical experience suggests that they can be a problem. Individual variation plays a role in how our bodies tolerate these foods.
Five key guidelines to success
For those who need more help, here are the keys.
1. Guidance: Find a physician with whom you can work.
It’s best to look for a doctor who is well-informed about LCHF/ketogenic eating, or who is at least open-minded and willing to do the necessary homework.
2. Goals: establishing reasonable objectives
A few weeks are not enough, just as they’re not enough to know whether quitting smoking or alcohol is worth the effort. I would say three months is a minimum, ideally six – long enough to get a realistic feel for what is possible.
If you want to shift to this new way of eating, slowly, a step at a time, the obvious first step is to start with an essential requirement for any rational approach to weight loss, weight control, and healthy eating, regardless of the belief system: Stop eating and drinking sugar.
The most common side effect is what used to be known as the “Atkins flu,” now typically known as the “keto flu.” Symptoms are temporary, but they can include headache, fatigue, nausea, lightheadedness, and constipation. You can avoid the keto flu or reduce the symptoms by making sure you’re eating sufficient fat and, more specifically, by replacing the sodium and water you’re losing.
Sustain what you started in a world that makes it as difficult as possible by planning ahead for experiences and environments that are likely to weaken your resolve. Among the habits you have to form and reinforce is that of thinking ahead about what you can and cannot eat at events like office parties, in airports and on flights, on vacations, and at holiday meals.
If you expect no LCHF/ketogenic-friendly foods will be available, then plan to bring your own. If you were a vegan or a vegetarian, this is how you would approach such situations without a second thought.
A greater implication of this power-of-the-environment phenomenon is that you will more likely succeed if your family eats the same way you do.