The case for the keto diet
Is a high-fat, low-carb diet really the answer to building a leaner and healthier body? We investigate
Following the low- carb, high- fat ketogenic or “keto” diet won’t just help you lose weight, exercise more efficiently, feel better and generally improve your life; it may also fight cancer and wipe out diabetes forever… and even boost your chances of getting to Mars. Don’t take our word for it – that’s according to leading biohackers, US Special Forces and even Nasa. So what is it and how can you make it work for you? One of the world’s most accomplished exercise physiologists explains over the page.
While his name may not ring many bells on these shores, Timothy Noakes – emeritus professor in exercise science and sports medicine at the University of Cape Town – is a full-blown celebrity in his home country of South Africa and one of the most accomplished exercise physiologists on the planet. You can’t walk by a restaurant in Cape Town that doesn’t offer a “Noakes option”- say, an avocado stuffed with breakfast sausage and eggs, or a double cheeseburger with lettuce and no bun - and evidence of his teachings is everywhere. He’s been endorsed by some of the nation’s best-known athletes, including ageless golfing legend Gary Player and eight-time Ironman world champion Paula Newby-Fraser (who said Noakes “has had the most influence on how I viewed endurance sports”). And Noakes even has fans at the very top of government – he was invited to address Parliament on nutrition in 2014, while President Jacob Zuma’s wife Thobeka lost around 30kg in a year following the Noakes plan (the president himself is rumoured to be on it too).
To high-performing athletes, Noakes preaches that the long-accepted bedrock tenet of endurance athletic nutrition – that winning performance is best fuelled by eating lots of carbohydrates – is simply wrong. Instead, he believes athletes can alter their bodies so that their metabolism burns fat as a primary fuel source, a physiological process known as ketosis, either from stored body fat or from the foods they eat.
But for non-athletes and anyone trying to lose weight or keep it off, Noakes’s advice is that eating a high-fat diet, with few if any refined carbs and as little sugar as possible, will switch on the same fat-burning system and keep your body lean and your weight stable without making you hungry. According to Noakes and a growing number of nutritionists, physiologists and biohackers, when you’re in a state of ketosis – best attained by following a strict ketogenic diet – good things happen to your body.
In 2014, basketball superstar LeBron James lost 11kg and upped his late-game endurance after cutting carbs and sugars
from his diet for two months. The same year, ultra-fit property entrepreneur Sami Inkinen rowed with his wife from California to Hawaii in record time on a keto diet, partly in an attempt to promote high-fat eating and raise awareness about the dangers of too much sugar. Tim Ferriss, author of the 4-Hour self-improvement book series, says following a strict keto diet cured his Lyme disease and performs a multi-day
fast every four months with the aim of pushing ketosis further and starving incipient pre-cancerous cells of sugar (more on that later). The keto diet, say its supporters, is a natural way to reprogramme your metabolism and upgrade your body’s operating system. You’ll feel better, you’ll perform better and your body fat will plummet.
But this low-carbohydrate, high-fat (LCHF) diet – as Noakes calls it – is still far from mainstream. It takes serious dedication to drop your daily total carb intake to below 50g (or 20–30g of net carbs, which means without fibre), the equivalent of a mediumsize serving of brown rice. And in the US, government dietary guidelines were only changed in 2015 to mention limiting intake of added sugars and refined carbs (which spike blood sugar more rapidly than sweets), while in Britain NHS guidelines still maintain that a third of our calories should come from “starchy foods such as potatoes, bread, rice, pasta and cereals”. Sports drinks are often loaded with natural or added sugars, while supermarkets are packed with foods labelled “low fat” or “zero fat”.
While many governments (including the UK’s) still advise limiting all fats in the diet, Noakes has continued preaching that the right kinds of fats – the ones our bodies evolved to process, like animal fat, butter, olive oil and coconut oil – are extremely healthy. He called his 2012 memoir Challenging Beliefs, and he’s still waging a public war against carbs and sugar from his Twitter account, @ProfTimNoakes, with more than 33,000 tweets since 2012. The 67-year-old Noakes is constantly active on social media, sharing the latest nutrition stories as well as offering his own food for thought: “Consumption of refined grains, sweets and desserts, sugared drinks, and deep-fried foods = more heart disease” or “Truth wins in the end. But it takes time.”
Noakes’s war on sugar goes back a generation to when his father developed type 2 diabetes,
a disease that causes the body to gradually lose its ability to regulate blood sugar through the production of the hormone insulin. It’s linked to genetics, but also to diet – particularly sugar and refined carbs – as well as obesity and inactivity. Diabetes experts say the disease speeds up the ageing process by roughly a third as excess blood sugar slowly destroys blood vessels, with results ranging from mild – early wrinkling of skin – to catastrophic: heart disease, blindness, stroke, amputations owing to poor circulation, and even Alzheimer’s disease.
Noakes’s father eventually died from type 2, but because Noakes himself followed a low-fat diet, exercised regularly (he’s run more than 70 marathons and ultras) and didn’t smoke, he figured he’d be spared. To be sure, as he got older he put on some weight, and his energy sagged, but he was in good shape.
In 2010, though, Noakes was diagnosed with type 2 diabetes. He didn’t know it yet, but a lifetime of well-intentioned carbloading for his athletic endeavours had set him up for a fall.
Not long after he got the diagnosis, he happened to receive an email about a book titled The New Atkins For A New You, and recognised the names of the authors – respected academics and exercise experts Stephen Phinney, Jeff Volek and Eric Westman. They argued that the late Robert Atkins, who famously promoted a low-carb, high-fat diet in the 1980s and was routinely lampooned for championing eggs, bacon and cheese as healthy foods that helped you lose weight, had been right all along. The professors backed up their position with more than 50 new dietary studies and an action plan for getting and saying lean. Noakes says he learned more about nutrition that year than in his previous four decades as a doctor.
“I was 100kg when I picked up that book,” he tells MF. “Today, I’m 80kg. I’ve achieved my high school weight and my old running times.”
His new way of eating, he says, eliminated spikes in blood sugar, kept his appetite in check and allowed his body to burn its own fat stores as fuel. On top of that, it cured his migraines and acid reflux – and he also discovered that his diabetes had reversed course. When he wrote about his experiences and results in Discovery Health News in South Africa, the article triggered a national debate across a country plagued by an epidemic of diabetes and its associated conditions. (Black Africans and ethnic Indians, who make up more than 80% of South Africa’s population, are especially prone to the disease.) In 2015 Noakes published his fourth book, The Real Meal Revolution, which explains why high-fat diets work and how to incorporate them into everyday life. “It’s gone viral,” he says. One place it’s been enthusiastically adopted is
among biohackers in Silicon Valley - people attempting to modify their own genetics with the aim of enhancing their bodies.
Other diets prescribe high fat and low carb intakes – the Paleo, Zone and South Beach diets all restrict sugary foods and refined carbs,
while the standard low-carb diet is usually called Banting in South Africa, after the 19th-century undertaker who was an early proponent – but the ketogenic diet has taken this to a whole new level. Here’s how it works.
Ketones are molecules formed by the breakdown of stored fat, and they’re an important fuel for the body. In fact ketosis, the process by which the body uses those fuels, is essential for survival. The human body – even that of a very lean athlete – stores about 40,000 calories of fat and just 2,000 calories of the carbohydratederived form of glucose called glycogen. When the glycogen is depleted, the body taps its fat stores for energy. That’s what happens when athletes “bonk” during exercise – they’ve used up all their stored glycogen. To go on, they must either eat more carbs (to burn as sugar) or start burning fat. When marathoners break through the so-called “wall” late in a race, they’ve begun to burn fat.
A growing number of athletes today prefer to be in that state at all times, thanks in part to Noakes and other keto diet promoters. Once they make the switch, they say, not only are their race results and game-day performances better, they report sustained energy, better moods, and clearer thinking.
Switching from foods that are linked to chronic illness and make you fat to foods that keep you permanently lean and energetic without getting hungry would seem like a no-brainer. But it’s not as easy as that. The predominant Western diet makes us into what nutrition experts call “sugar burners” – we ingest carbs for breakfast, so our blood sugar goes up quickly then crashes down before lunch, when we get our next carb fix. The process happens over and over again and our bodies never enter ketosis.
But getting your body to enter full ketosis is no small feat. You have to forgo all starchy vegetables, breads, sugary drinks (including fruit juice), pasta – essentially everything that isn’t meat or a non-starchy vegetable. It’s a tall order that gets taller, because once you’ve started the process the body, feeling deprived, undergoes a transition phase often termed “low-carb flu”. For a few weeks, physical and mental performance – at work, in the gym – dips noticeably and uncomfortably as the body tries to tap its missing fuel source. Not everyone sticks it out. (For more on what it’s like to go full keto, see “The Road To 7% Body Fat” on p76.)
There’s a shortcut to ketosis, however: fasting. If you don’t eat for many hours, your body will naturally go into fat-burning mode. There are many different fasting protocols to get into ketosis, but the most common is called intermittent fasting, which consists of not eating for 12 to 16 hours. For instance, you could can eat dinner at 8pm, skip breakfast the next morning, and eat lunch at noon. Or, like Mark Mattson, chief neuroscientist at the US National Institute on Aging, you can push it even further. Mattson regularly skips breakfast and lunch altogether and says that with no blood sugar spikes and crashes, just steady fat burning, he feels mentally sharp and experiences little if any sense of deprivation.
If all of this sounds like too much misery for you, consider another reason for going keto:
evidence shows that ketosis could help stave off diseases including Alzheimer’s and cancer.
In 2007 Dominic D’Agostino, a neuroscientist and physiologist then at the University of San Francisco, was trying to solve a serious problem for the military divers. They use a device called a rebreather, which recycles exhaled breath and allows for extralong dives but also, for reasons that still aren’t fully understood, makes divers prone to life-threatening oxygen toxicity seizures.
While looking for a way to treat these seizures, D’Agostino stumbled upon the ketogenic diet, which is
a proven treatment for a possibly related malady: epileptic seizures in children. “There are a lot of treatments for epilepsy,” he says, “but the only one board-certified neurologists can say [successfully treats] the disease is the ketogenic diet.”
Why? D’Agostino believes the diet remedies a metabolism imbalance in which brain cells are starved of, or unable to process, glucose, causing the brain to go haywire. Live brain cells are extremely difficult to study (for obvious reasons), but researchers have been able to tease out some clues from the petri dish about why keto diets are good for the brain. Aside from being an energy source, ketones also seem to modulate the stress response in neurons and make them more resilient to excitatory nerve transmissions – the kind that can cause seizures. D’Agostino also found that ketones can elevate levels of the calming neurotransmitter GABA.
Theories aside, when he treated the divers with a keto diet, their seizures stopped.
Brain diseases aren’t the only illnesses doctors are beginning to think are metabolic rather than purely genetic in origin.
Many common types of cancer – esophageal, pancreatic, colon, kidney, thyroid – are associated with obesity and diabetes, and D’Agostino believes he’s on the path to understanding why.
Cancer cells thrive in high-sugar environments because they rely on glycogen to survive; type 2 diabetes, especially, provides potential cancer cells with a high-sugar environment. (In fact, PET imaging scans detect cancer by finding areas in the body with excess glucose compared with normal tissues.) This suggests not only that glycogen may contribute to cancer, but also that it may be cancer’s achilles heel: if cancer cells become compromised when their host is in a ketogenic state, the body’s own immune responses may be able to fight the disease effectively.
“We think the majority of cancers could be metabolically managed through nutritional ketosis, either as a standalone pill or an adjunct to standard care,” says D’Agostino, now at the University of South Florida College of Medicine, who has published research showing that ketogenic diets can double the lifespan of mice with metastatic cancers. A leading cancer researcher at Boston College, Thomas Seyfried, says his research has lead him to believe that a ketogenic diet is therapeutically even more valuable in fighting cancer than chemotherapy.
Achieving a ketogenic state could get a lot easier in the coming years. D’Agostino believes a ketone supplement will be the breakthrough,
making the job of drastically cutting carbs from the diet much easier. He has created KetoCana, which floods the body with ketones and eliminates the symptoms of carb withdrawal.
Meanwhile, military researchers are focusing on keto diets as well, believing soldiers could operate optimally on fewer, denser meals. In the US, the Defense Advanced Research Projects Agency, the Department of Defense and Nasa have all run ketogenic experiments. Nasa believes the diet will be important in manned missions to Mars because it protects against higher levels of radiation in space by increasing the brain’s resilience to stress. Plus, says D’Agostino, “the energy density of a ketogenic diet is higher, so you have to carry less weight”.
But for evidence of the keto diet’s more immediate effects, Noakes cites South African athlete Bruce Fordyce, now 61, who won the country’s biggest ultramarathon, the 89km Comrades, a record nine times from 1981-1990. He ate high-carb his whole life, eventually putting on weight and becoming insulin-resistant. Recently, though, he switched to a high-fat diet. “Simply by reducing my carbohydrate intake and especially junk carbohydrates I shed 13kg, and reduced my Comrades time from 9hr 48min to 7hr 30min and broke three hours for the standard marathon for the first time in many years,” Fordyce wrote at citizen.co.za.
Little by little, says Noakes, we’re learning. “This is the single most important health intervention we can make as doctors,” he says. “And as nations.”