Former dental surgeon Kamala Christie will celebrate her 60th birthday at the end of the week with a body that she has not seen since her kids started arriving nearly three decades ago.
"I used to be a double XL, and now I am a size M," says Ms Christie, who has five children.
"Over the years, I put on the kilos and never lost them. My youngest child is already 18."
Worried about the impact of her 76kg frame on her health, she went on the low-carb ketogenic diet at the start of the year and lost 1kg a week over 16 weeks.
In May, she lost a further 2kg and is now at her target weight of 58kg.
The ketogenic diet has been gaining considerable attention as an effective weight-loss option in recent years. It remains a craze in the United States, having been linked to Victoria's Secret supermodel Adriana Lima and celebrities such as Halle Berry and Kim Kardashian. There's a Facebook page here for those who follow the diet.
Unlike other low-carb diets such as the Atkins or Paleo diet, the keto method is exceptionally high in fats and low in carbs, with a moderate protein intake.
While doing research online, Ms Christie found that the low-carb diet was attainable and promptly stopped eating carbohydrates such as rice, bread, noodles and pasta and cut out sugar intake.
"I wouldn't call it a diet, it's a new way of eating for me," she says. "Strangely, I don't miss the sugar and starches."
UP THE FATS
Glucose, which comes from eating carbs, is our body's preferred energy source. Carbs often make up at least half of a typical diet.
If you eat a lot less carbs, your body will have to look for an alternative fuel source. It will then start to break down stored fat for energy in a process called ketosis. This produces ketones, which are chemicals that the body creates when it burns the fat for energy.
Carb intake has to be less than 50g a day for adequate ketosis to occur. Ketosis also happens during fasting or starvation or when one is eating very few calories, say, less than 500 a day.
"In the keto diet, you eat only 5 per cent carbs, 75 per cent fats and 20 per cent protein," says Dr David Heber, the US-based chairman of Herbalife Nutrition Institute.
But Dr Heber believes that 30 per cent of our diet should be protein, which helps to control hunger to help you lose weight or maintain it.
Those on the keto diet use high-fat foods such as butter, coconut oil, cheese, peanut butter, fatty fish and full-fat milk to control their hunger. And, instead of lean meats, dieters go for fattier cuts.
A meal for Ms Christie may consist of grilled pork belly and asparagus, or bacon, avocado and hard-boiled eggs. She also eats lots of cheese.
"If you don't increase the fats, you might get hungry. If I have to snack, I will have macadamia nuts or walnuts, for instance," she says.
"I used to use a non-stick pan to fry but now I use a lot of butter."
She also eats at least half an avocado a day although, on some days, she may blend it with almond milk and spinach or kale.
Instead of snacking on potato chips or cookies, she munches on broccoli, tofu pieces, hard-boiled quail eggs or raw capsicum slices.
She does not eat fruits unless they are sour, such as strawberries, blueberries and raspberries.
IS IT SAFE?
Fat does provide more energy. Every gram of fat has 9kcal while carbohydrates provide 4kcal, says Raffles Diabetes and Endocrine Centre principal dietitian Bibi Chia.
However, the high intake of saturated fats might increase bad cholesterol levels and heighten the risk of heart problems, she adds.
"Cutting out carbohydrates might lead to a lack of energy. If severe, it can lead to ketoacidosis."
Unlike ketosis, ketoacidosis can be life-threatening and mostly occurs in people with Type 1 diabetes whose bodies lack insulin. Ketoacidosis develops when your body produces dangerously high levels of ketones and blood sugar.
Dr Tham Kwang Wei, a senior consultant at the endocrinology department of the Singapore General Hospital, says she has seen people with dehydration, low blood pressure and worsening renal function after going on the very low-carb keto diet.
"However, once medical attention is sought, these were reversible," she says.
Generally, the diet is safe for the healthy or those with simple medical problems like high cholesterol or hypertension, though it is not without side effects, says Dr Tham.
Those with multiple other issues such as kidney failure, poorly controlled diabetes, or who are on medication such as diuretics, should seek medical advice first, he adds. The initial phase of such a diet leads to diuresis (loss of water) and the loss of potassium and magnesium.
While the water loss leads to initial rapid weight loss and a drop in blood pressure, it may also lead to dehydration. This may, in turn, lead to worsening kidney function in people taking diuretics or with kidney failure, notes Dr Tham.
Also, the low blood potassium and magnesium can predispose some people to cardiac arrhythmias, muscle cramps and weakness, she says.
When ketosis sets in, the blood becomes acidic, which may be detrimental to patients with renal failure as they already are unable to get rid of the acid in their body.
Also, gallstones development or cholecystitis and pancreatitis are a known risk for people who are losing weight rapidly, she adds.
WILL THE TREND LAST?
"Keto may be a fad diet, but it doesn't help to lose weight any faster than other diets. At the end of the day, it's about cutting calories," says Dr Heber. "It's possible to adapt to it but, for most people, they are going to be weak."
Ms Chia adds that "some people experience weight loss but it is likely due to a negative energy intake versus output".
According to the British Dietetic Association, which listed the keto diet as one of the top five diets to avoid this year, a carefully dietitian-planned ketogenic diet can be a very effective treatment for people with epilepsy. However, for weight loss, there's no magic, as the diet works like any other by cutting total calories and removing foods people tend to overeat, it said.
Initial side effects may include low energy levels, brain fog, increased hunger, sleep problems, nausea, digestive discomfort, bad breath and poor exercise performance, it noted.
The diet can be an effective method of weight loss in the short term with careful planning but it is hard to sustain for many in the long term and most of the initial weight loss seen is often associated with water or fluid losses.
"It is never a good idea to 'over-restrict' any one food group (including carbohydrates), as this can mean it is more difficult to achieve a balanced diet overall with respect to vitamins, minerals and fibre, in particular," the association noted.
Both Ms Chia and Dr Heber agree that the downside of the keto diet, as with many other diets, is that it is not sustainable.
"Nutrition is really about behaviour. There are so many stresses in life and people use food to cope with them," says Dr Heber.
Ms Christie has been very focused as she was determined to reach her target weight by the middle of this month. She plans her meals and sticks to them. For instance, if her family is having ice cream, she doesn't have any. She makes her own, with whipping cream and frozen berries. "I feel good, I have lots of energy and I sleep well at night," she says. "As long as I feel good, I will carry on."
IS THE KETO DIET SUITABLE FOR DIABETICS?
As a ketogenic diet is low in carbs, it will result in a near-immediate reduction in the blood sugar level of a diabetic, notes Dr Tham Kwang Wei, senior consultant at the endocrinology department at the Singapore General Hospital.
"It will ultimately help to improve the overall glucose control of a diabetic," she adds. "In a diabetic, the blood glucose variability after a meal can be rather large. There is some evidence that a low-carb diet can improve that."
While there is a definite benefit, there is also the risk of hypoglycemia or low blood sugar. So, the patient's diabetic and blood pressure medications may need to be pre-emptively reduced or his blood sugar and pressure closely monitored and adjusted accordingly.
A diabetic needs to closely monitor his blood sugar and pressure when embarking on any major dietary changes, says Dr Tham.
Studies of up to 24 weeks have shown that a keto diet is more beneficial than a low-fat, low-calorie diet in improving HbA1c scores (marker of diabetes control), lowering blood triglyceride levels and raising HDL-cholesterol levels.
However, the diet's sustainability may be a challenge, which is why longer-term studies show that there are no differences between the diets, and the effects are not sustained. Dr Tham says these effects can also be seen with other diets as they often place patients on very low-calorie diets (though not necessarily a very low-carb one).
"Within a few days of initiation of the diet, we will see dramatic improvement in the patients' blood sugars and blood pressures, with a need to reduce their medication for diabetes and blood pressure."
It is also not clear if the keto diet can do harm over the long term. As yet, there are no long-term studies on the benefits of the keto diet in terms of mortality and cardiovascular outcomes, especially in diabetics, Dr Tham says. Those on the keto diet may consume a lot of saturated fats from animal sources, which have been shown to be detrimental to health in the general population, she says.
A low-carb diet that features complex carbs like wholegrain foods and is rich in unsaturated plant fats could be easier to adhere to and has been shown to have cardiovascular benefits, she adds.
Source: The Straits Times © Singapore Press Holdings Limited. Reproduced with permission.