The low-carb keto diet might be popular among weight-loss warriors and celebrities today, but did you know it was first given to kids with a particular form of epilepsy?
The ketogenic or keto diet was developed in the 1920s by Dr Russell Wilder at the Mayo Clinic. He prescribed it to children with severe epilepsy who weren’t responding to drugs, and found the diet minimised the frequency and severity of their seizures. Although, a recent study has shown not all children benefit from the diet.
It wasn’t until the 1960s when Dr Robert Atkins created his eponymous diet that low-carb eating plans became popular among the masses.
Dr Atkins theorised that when we consume minimal carbohydrate, the body burns fat for energy. This process is known as ‘ketosis’ — more on that in a minute.
So, how does it work? What can you eat on the keto diet? And what does the research say about its connection to weigh loss? Are there any side effects? Let’s dig in.
How does it work?
While Dr Atkins recommended dieters limit their carbohydrate intake to 65-100 grams per day, keto requires even greater self-control.
“To become ketotic you need to take your carbohydrate down to 10 grams, 20 grams a day,” says Monash University’s head of dietetics, Professor Helen Truby.
Becoming ketotic — or entering ketosis — is the physiological process when your body stops using carbohydrates for energy and starts using fats.
And the energy can come from fats you’ve eaten, as well as fats stored in the body, says New York University physician Shivam Joshi, who spoke with Dr Norman Swan about keto on RN’s Health Report.
“But when you look at low-carb diets in general, the sentinel feature of their ability to cause weight loss is that they restrict calories,” he says.
It can take up to five days to become ketotic, and when you do your body will start producing ketones, which are another energy source.
In addition to using fat as an energy source, Professor Truby says after a few weeks in ketosis, you become less hungry.
What can you eat on the keto diet?
In a review of the keto diet, Harvard University’s School of Public Health points out that “there is not one ‘standard’ ketogenic diet with a specific ratio of macronutrients [carbohydrates, protein, fat]”.
“Generally, popular ketogenic resources suggest an average of 70-80 per cent fat from total daily calories, 5-10 per cent carbohydrate, and 10-20 per cent protein.”
Sample menu on the keto diet:
Breakfast: Green smoothie made with spinach, cucumber, avocado, coconut cream and peanut butter
Snack: Low-carb chocolate with peanut butter
Lunch: Baby spinach, egg and parmesan salad
Snack: 100g cheese with cucumber
Dinner: 50g piece of salmon with baby spinach and garlic oil
Dessert: Hot chocolate made with coconut cream and sugar-free drinking chocolate
Beyond pasta and rice, carbohydrates are found in plenty of healthy foods, including fruits and many vegetables, legumes, wholegrains and the natural sugars found in milk and yoghurt.
Due to this, Professor Truby says it’s important for people on the keto diet to be mindful of their micronutrient intake.
Micronutrients include minerals like calcium, which is important for bone health, B vitamins in legumes and wholegrain foods, and vitamin C, which is found in fruit.
Professor Truby says keto dieters might need to take micronutrient supplements to ensure their needs are being met.
Those coming off a keto diet may also experience some weight gain.
“Your body will try and put some of that weight on again, unless you’re really careful about how much energy and how many carbs you have,” says Professor Truby.
She recommends easing back into carbohydrates slowly, and choosing healthier carbs, like fruits and wholegrains, over sugary items.
“In my opinion, if you’re going to try a diet that induces ketosis, you should have a chat with your GP first, particularly if you’ve got any medical conditions,” Professor Truby says.
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What does the research say?
The keto diet is no silver bullet.
“Questions remain concerning the long-term health effects of this diet on the gut microbiome and general health given the lack of fruit, vegetables and grains,” says this post from Monash University’s Department of Nutrition, Dietetics and Food.
In a paper co-written for the JAMA Internal Medicine, Dr Joshi analysed a series of randomised controlled trials over a year or more.
“This study showed the difference in weight loss between those on a ketogenic diet and those not on a ketogenic diet or a control diet was only 0.9 kilograms, which is of statistical significance but may not be of clinical significance,” he says.
And Harvard’s School of Public Health ends their assessment of the keto diet with this summary:
“Available research on the ketogenic diet for weight loss is still limited. Most of the studies so far have had a small number of participants, were short-term (12 weeks or less), and did not include control groups.
“A ketogenic diet has been shown to provide short-term benefits in some people, including weight loss and improvements in total cholesterol, blood sugar, and blood pressure. However, these effects after one year when compared with the effects of conventional weight loss diets are not significantly different.”
Experts say the keto diet may cause a range of side-effects. These include:
- Unpleasant-smelling breath.
- Dizziness and feeling faint (especially likely if you reduce your carb intake too rapidly).
- Keto ‘flu’ with lethargy and flu-like symptoms in the early stages.
- Constipation (due to restrictions on wholegrains, fruit and some vegetables).
- Adverse effects on the gut microbiome and general health due to lack of wholegrains, yoghurt, fruit and some vegetables.
- Although losing weight generally improves cardiovascular risk factors, Dr Joshi notes that studies show an increase in LDL cholesterol and apolipoprotein B — both risk markers for heart disease.
- Professor Truby also adds that those with diabetes or issues related to glucose metabolism may find a keto diet impacts their medications.
Professor Truby says the keto diet may have positive effects for people who are very overweight.
“[Through shedding fat] your blood pressure should come down, your lipid levels will change, and you get better glucose control,” she says.
But it’s probably not worth it for most people.
“For people who just want to lose a little bit of weight, then I don’t think a ketotic type of diet is really necessary because you will actually regain the weight anyway, when you stop being ketotic,” says Professor Truby.
But maybe we can all take a slice of advice from this popular eating plan, she adds.
“There’s no need for everyone to go on a completely keto diet, but reducing those carb sources that are not nutrient-rich — things like cakes, biscuits, chips — is a good idea for everyone.”
This is general information only. For detailed personal advice, you should see a qualified medical practitioner who knows your medical history.
This article has been reviewed by Dr Rosemary Stanton OAM, nutritionist and visiting fellow, School of Medical Sciences, University of NSW. This is general information only. For detailed personal advice, you should see a qualified medical practitioner who knows your medical history.
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