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Weight Loss Revolution: Why scientists are worried about ketogenic diet
An increasing number of Nigerians are embracing the controversial ketogenic diet. This diet has shown dramatic weight loss but its effect on dieters is highly open to question. The keto diet is based on unproven scientific claims, especially with regard to its long-term efficacy and safety.
Justina Ude, 35, loved to show off her figure and flaunted her body like a model. But the visible excess fat she carried gave her no confidence for the red carpet pose until she was introduced to a miraculous diet that appeared to have changed her life for good.
She achieved a dramatic weight loss of 31 percent within one year of going against conventional dietary advice. All she had to do was to deny herself intake of carbohydrate and consumed more high-fat foods.
“Ketogenic lifestyle is indeed the best lifestyle,” Ude says excitedly. “I can’t believe it’s a year already I embarked on this journey. From 120kg to 82kg, still ketoing hopefully I will get to 75kg.”
A balanced diet is ideal for healthy living, according to the mainstream dietary recommendation, but not anymore with the ketogenic diet that is helping people like Ude to achieve their goal of weight loss.
In Nigeria where the quantity of carbohydrate is always higher in most meals –among the classes of nutrients except water – she fastidiously upheld the dietary regimen of Low Carbohydrate High Fat (LCHF). This diet put the body into ketosis, upon which ketogenic or keto diet is derived.
The success story of the ketogenic diet is a deluge, especially among people who have been struggling with weight loss for a long time. According to 2017 Global Nutrition Report, 40 percent of Nigerian women are overweight and 15 percent are obese while 24 percent of men are overweight and 5 percent obese.
Obesity is as much a public health problem as undernutrition. Nigeria has the double burden of malnutrition – a growing health problem that affects many developing countries. Obesity is not just a forerunner of diabetes but also has been linked to cancer. A new study, published in the medical journal The Lancet Diabetes and Endocrinology, found that diabetes and obesity accounted for nearly 6 percent of new cancer cases.
While losing weight does not always equate to good health, conscious effort to decrease body weight through healthy diet and physical activity have been found to reduce the risk of non-communicable diseases.
Conventional medical advice for weight loss has consisted of low-calorie and low-fat diet as well as eating less and exercising more. This dietary advice has done little to help already overweight and obese people to lose weight. Rather, obesity and diabetes have been on the rise worldwide.
QUICK FIX, THE KETO WAY
Carbohydrate-restricting diet for weight loss is not new. In the 17th century, William Banting, a British undertaker was highly overweight. After changing to low carbohydrate diet – on the advice of William Harvey, a medical doctor – Banting had a drastic weight loss and felt healthier. Harvey wrote about the experience in 1862. In some countries, like South Africa, LCHF is known as Banting.
Robert Atkins, a cardiologist, published his Diet Revolution in 1972 in which he recommended a carbohydrate-restricted diet with increased protein as well as saturated fat intake. While keto diet has to do with high fat with moderate protein, Atkins diet dwells on high protein with the total fat intake.
While the claims of LCHF diet on weight loss are controversial, it has been found to have significant therapeutic effects on certain diseases. The ketogenic diet has an anti-seizure effect, according to a systematic review published in the journal Neuropharmacology, and can be used in the treatment of epilepsy. The diet is also showing promise for the treatment of Alzheimer’s disease, according to a study published in the journal Food Science and Human Wellness.
The argument for ketogenic diet focuses on insulin resistance which is considered the major driver of obesity and diabetes epidemic. Promoters of keto diet have argued that the conventional dietary advice does not account for insulin resistance. Insulin facilitates the uptake of glucose by cells in the body to be used to produce energy or to store it as fat. When the body becomes insulin resistant, it means the body cells are unable to take up glucose into the cells and this causes glucose to build up in the blood. In response, the person produces more insulin but still is hard for the excess insulin to drive glucose into the cells.
This insulin resistance can put a person at high risk of developing type 2 diabetes mellitus or gestational diabetes if not well managed. One of the main causes of insulin resistance is an intake of a high-calorie diet, high-carbohydrate or high-sugar diet, weight gain and sedentary lifestyle.
When the body takes in carbohydrate, it is digested and converted into glucose for energy. If the carbohydrate is excess, the body spends as much as it can and store the remaining as glycogen in the body which makes the consumer gain weight. Also, insulin is released as soon as a person consumes carbohydrates to help in driving the glucose into the cells.
The essence of the ketogenic diet is that it denies the body of carbohydrate, the main source of energy. When this happens, the body goes into ketosis where it is forced to burn stored fat and glycogen as well as dietary fat for energy, rather than carbohydrate. This also helps in regulating the release of insulin and minimises the risk of insulin resistance.
To maintain body weight, the amount of energy intake must be equal to energy expenditure. And to achieve weight loss, negative energy balance is required. That is the amount of energy expenditure must be higher than energy intake.
Carbohydrate is the main source of energy in the body and ketogenic diet revolves around restricting carbohydrate to facilitate weight loss. In trying to restrict carbohydrate intake to near zero, ketogenic dieters restrict the type of foods they take and also take in a lot of high-fat foods. This raises the big question of how well the ketogenic diet can meet the nutritional demand of the dieters and the potential long-term effect of high-fat foods.
Ngozi Nnam, a Professor of Community and Public Health Nutrition at the Department of Nutrition and Dietetics, University of Nigeria, Nsukka, and former President of the Nutrition Society of Nigeria, who spoke to the ICIR, believes that ketogenic diet is not nutritionally adequate.
“When we say that diet is adequate, that diet has to contain all the food nutrients,” Nnam explains. The problem with ketogenic, she says, is that the body is not using the normal source of energy that some organs in the body need to function properly.
“I know that many people on ketogenic diet avoid fruits and vegetables that contain carbohydrate. They avoid whole grain food that contains carbohydrate. They are losing on some vital nutrients that are needed for the body to function well.”
Nnam argues that the good way to lose weight is to eat a balanced diet at a moderate portion so that no nutrient will be marginalised and also do a lot of physical exercises to burn the excess energy or already accumulated body fat.
A study, published in The Lancet Diabetes and Endocrinology, has shown that Ketogenic diet facilitates weight loss but its safety and efficacy in the long term is still largely unknown and will require randomised clinical trials.
KETO CRUSHES BODY FAT
The ketogenic diet holds much promise in curbing the global rise in obesity and non-communicable diseases if eventually the diet gains scientific consensus.
Without exercise, Chekwube Nnaji achieved 10kg weight loss within three months by simply sticking to the ketogenic diet plan. She replaced her garri “swallow” with eggplant and cabbage swallow. She made cauliflower rice instead of the normal rice. She turned to coconut flour and used coconut and olive oil. She ate a lot of meat, fish, and avocado.
To maintain her abstinence from carbohydrate, she shunned sugary foods, grains, starchy roots, fruits and vegetables like a carrot.
“Keto makes you look much younger than you are,” Nnaji told the ICIR. “It reduces every part of your body – your tummy, your hand, every part normalises. People were coming to my office to ask me what I was doing and a lot of them joined.”
Since she embarked on the keto diet, Nnaji says, she has become healthier than she used to be. The problem was having fatigue and headache when she started on a keto diet. But that did not last more than a week, she says.
Joy Aghogho, the host of one of Nigeria’s biggest online ketogenic diet support groups with over a million members, explains that starters on keto diet usually have certain symptoms.
“You may have the keto flu also known as carbs withdrawal. A very common happening when people start a ketogenic diet is getting headaches and “brain fogginess.’”
With a growing number of Nigerians taking the keto diet for weight loss, the diet has created business opportunities. Ketogenic markets have sprung up in major cities across the country. In Lagos, Port Harcourt and Enugu, suppliers of ketogenic products are using Whatsapp and Facebook to sell their products and keto-compliant restaurants are the new rave.
However, not every overweight person is keen on consuming keto diet. “My younger sister lost 4kg within a week of starting keto,” Chioma Eze, a lawyer, told the ICIR. “But I can’t do that diet. I love my fried plantain biko.”
THE FOOD FIGHT
Through the ages, scientists have classified food into six classes: protein, carbohydrate, fat and oil, mineral, vitamin and, water. Scientific evidence suggests that it is better to eat a diet that that has all the food groups.
A study conducted by Catherine Champagne and her team which was published in the journal The American Dietetic Association points out that a great deal of interest surrounds the question of what dietary changes may be most effective in weight loss and maintenance efforts. The study which utilised 828 successful weight loss participants in randomized controlled trial concluded that “increases in fruits, vegetables, and low-fat dairy, as part of a calorie controlled diet, help both achieve and maintain weight loss”.
Certain studies, however, suggest that low fats intake causes weight loss in the short term while other studies suggest that low carb diet with high fat and high protein achieves a better result for weight loss.
The DASH diet has consistently ranked the best diet, by the U.S. News and World Report, in lowering blood pressure as well as being effective for weight loss and weight maintenance. It recommends eating a diet rich in fruits, vegetables, whole grains, low-fat dairy, and lean proteins. In addition, the DASH recommended food sources that are also low in sodium but rich in potassium, calcium, and magnesium. DASH means Dietary Approaches to Stop Hypertension.
The World Health Organisation (WHO) recommends that reducing the amount of total fat intake to less than 30% of total energy intake helps prevent unhealthy weight gain in the adult population. According to WHO, the risk of developing non-communicable diseases is lowered by reducing saturated fats to less than 7-10% of total energy intake, and trans fats to less than 1% of total energy intake, and replacing both with unsaturated fats, reduced intake of free sugars to less than 5- 10% of total energy intake, increased dietary fibre to at least 20g daily intake and reduced salt intake.
Ketogenic diet contradicts these WHO recommendations as well as previous research findings on the effect of high consumption of dietary fats such as high cholesterol which is a risk factor for heart disease.
“You might be getting an immediate and positive result from keto diet but what about the long run effect,” asks Rachael Fakunle, Head of Dietetics Department, University College Hospital, Ibadan. “Whether you call it healthy or unhealthy fat, fat is fat. When it is in excess, it can cause a lot of damage to the organs.”
Fakunle urges people on Keto diet to consider the long-term effect, rather being driven by the immediate benefit of achieving dramatic weight loss.
Existing scientific consensus favours reducing the level of dietary fats as a means to prevent heart disease. However, scientists like Tim Noakes who advocate for keto diet see no adverse effect for high consumption of dietary fat. He is a professor in the Research Unit for Exercise and Sports Science in the Department of Human Biology, the University of Cape Town and the Sports Science Institute of South Africa, Cape Town, South Africa.
“In answer to your question: does it mean that all we have been told about animal fats and cholesterol as a risk factor for heart disease is invalid? The answer is a very strong yes,” Noakes responds to an inquiry by the ICIR.
“It is diabetes and insulin resistance and a high carbohydrate diet that causes arterial disease,” he insists.
Noakes has been a vocal supporter of LCHF diet since he joined the movement in 2012. He has published academic articles, written books and established a foundation to promote ketogenic diet. He once advised a nursing mother to wean her baby onto LCHF diet which he described as the real food. The Health Professions Council of South Africa subsequently instituted a professional misconduct case against Noakes based on this advice.
The conflicting and confusing messages from notable scientists put people at a loss for what to believe. At the moment, however, the weight of scientific evidence is at odds with a keto diet. The majority of scientists perceive ketogenic diet to be extremely dangerous with unproven and exaggerated scientific claims.
This article was made possible through funding from the Africa Science Desk, an initiative of the African Academy of Sciences and partners.