A new study suggests that low carbohydrate diets are unsafe and should be avoided, while another landmark study has concluded that high fibre cuts heart disease risk.
Low carbohydrate diets have been popular for decades, and come with their own scientific backing so who should you believe? We asked two local specialists for their take on the low carb diet.
Expert insights on the diet debate
Dr Alkesh Magan, a specialist Physician & Endocrinologist in the Division of Endocrinology Diabetology and Metabolism at the Centre For Integrative Health at Sandton Medi-Clinic in Johannesburg, says that perhaps the take-home message from this new research is that unrefined grains are beneficial.
“…Bear in mind that the Mediterranean diet has also been advocated for heart health by virtue of its minimal impact on elevating blood glucose,” he says.
The key components of a Mediterranean diet include:
- Eating primarily plant-based foods, such as fruits and vegetables, whole grains, legumes and nuts. Replacing butter with healthy fats such as olive oil and canola oil.
- Using herbs and spices instead of salt to flavour foods.
- Limiting red meat to no more than a few times a month.
- Eating fish and poultry at least twice a week.
- Getting plenty of exercise.
- Drinking red wine in moderation.
A study done of more than 1.5 million healthy adults demonstrated that following a Mediterranean diet was associated with a reduced risk of cardiovascular mortality as well as overall mortality. This is because this type of diet has been associated with a lower level of oxidised low-density lipoprotein (LDL) cholesterol — the “bad” cholesterol that’s more likely to build up deposits in your arteries5.
Don’t forget the fibre in a low-carb diet
Dr Rosetta Guidozzi, a General Practitioner from Johannesburg, says that when she refers to a low-carbohydrate diet, she is essentially implying the reduction or exclusion of refined carbohydrates, such as sweet beverages, sweets, cakes and white bread. Adherents certainly require an adequate intake of unrefined carbohydrates such as whole-wheat breads, brown rice, sweet potato and bulgur wheat, for example.
Dr Guidozzi explains that fibre is important in the human diet as it plays a number of different roles:
- It improves satiety so people feel full sooner and for longer.
- It slows down the absorption of sugar from the gut resulting in a gradual increase and decline of sugar levels in the blood after eating.
- It prevents the sudden peaks in blood sugar levels when there is no fibre in food. This stresses the pancreas less and prevents the person from becoming hungry soon afterwards.
“It is important to keep blood sugar levels under control because sugar in the blood (glucose) has a direct inflammatory effect on the wall of the arteries and high levels of glucose in the blood in the long term leads to damage of the arterial walls … and is responsible for cardiovascular disease,” she says.
Fibre also prevents the reabsorption of cholesterol from the gut, thereby reducing the amount of cholesterol that is taken in.
“Fibre increases transit time of digested food along the gut; therefore there is a decrease in the contact time between carcinogenic agents present in the digested foods and the gut wall. So in fact carcinogenic agents are excreted at a slightly faster rate,” she adds.
Dr Guidozzi also stresses that fibre is most important for the micobiome or bacteria which reside in our gut. “There is major research taking place at present on the beneficial and important role that this bacteria which forms the microbiome in our gut plays,” she says.
Serious health risks associated with lack of sufficient fibre
The study conducted by researchers at the Medical University of Lodz, Poland, claimed that while low carbohydrate diets may be useful in the short term to lose weight, lower blood pressure, and improve blood glucose control, in the long-term they are linked with an increased risk of death from any cause, and deaths due to cardiovascular disease, cerebrovascular disease, and cancer.
The study, the results of which were published in the European Society of Cardiology in August last year, found that the reduced intake of fibre and fruits in a low carb diet and the increased intake of animal protein, cholesterol, and saturated fat may play a role, as might the differences in minerals, vitamins and phytochemicals.
A landmark review commissioned by the World Health Organization found that eating more fibre, found in wholegrain cereals, pasta and bread as well as nuts and pulses, is associated with a decrease in heart disease and early death.
In fact, among those who ate the most fibre, the study found a 15-30% reduction in deaths from all causes, as well as those related to the heart, compared with those eating the least fibre. The report stated that while sugar is a “bad” carbohydrate and fibre is found in “good” carbohydrates, the overwhelming backlash against sugar is what has led to popular diets that reject carbohydrates, including the fibrous sort that can, according to this research, save lives.
The Mediterranean diet offers diverse health benefits
The Mediterranean diet is also associated with a reduced incidence of cancer, and Parkinson’s and Alzheimer’s diseases. Furthermore, women who eat a Mediterranean diet supplemented with extra-virgin olive oil and mixed nuts may have a reduced risk of breast cancer5.
It is for these reasons that so many major scientific organisations encourage healthy adults to adopt a diet similar to the Mediterranean diet for prevention of major chronic diseases5.
Dr Magan points out that the Mediterranean diet contains very little processed food, while Dr Guidozzi uses the example of whole corn on the cob, which would be a good choice to eat. “Polenta or pap which is super refined, would be a poorer choice. We need to eat grains with their skins on and we need to be able to chew our foods,” she says.
What seems to be at the forefront of all these studies is the need for the inclusion of minimally processed fibrous foods in our diets.
Prescription medication together with lifestyle adjustments such as a healthy eating and exercise plan, can help kickstart a weight loss journey, or can help someone get back on track. Speak to your doctor about options for weight loss management or go to www.ilivelite.co.za for more information or for dietician formulated, kilojoule specific meal plans, which are initiated and guided by your GP for individualised kilojoule intake.
Author: Pedro van Gaalen
When he’s not writing about sport or health and fitness, Pedro is probably out training for his next marathon or ultra-marathon. He’s worked as a fitness professional and as a marketing and comms expert. He now combines his passions in his role as managing editor at Fitness magazine.