What’s the beef with low-carbohydrate diets?
What’s the beef with low-carbohydrate diets?
A new study suggests low-carbohydrate diets are unsafe and should be avoided while another landmark study has concluded high fibre cuts heart disease risk.
Low-carbohydrate diets have been popular for decades, and come with their own scientific backing – So what now?
Two SA specialists for their take on the low-carb diet.
A specialist physician/ endocrinologist in the division of endocrinology diabetology and metabolism at the Centre for Integrative Health at Sandton Medi-Clinic in Johannesburg, Dr Alkesh Magan, said 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 said.
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, 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 and even 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 and 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 arteries.
A general practitioner from Johannesburg, Dr Rosetta Guidozzi, said when she refers to low-carbohydrate diet. she is implying the reduction or exclusion of refined carbohydrates, such as sweet beverages, sweets, cakes and white bread, and most certainly an adequate intake of unrefined carbohydrates, such as whole-wheat breads, brown rice, sweet potato and bulgur wheat for example.
“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,” Guidozzi explained.
“The levels of blood sugar are important to keep 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.”
Damage to arterial walls is essentially responsible for cardiovascular disease, she said.
“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 said.
Guidozzi also stresses fibre is most important for the micobiome or bacteria residing 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 said.
One study 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 or cerebrovascular disease and cancer.
The study, the results of which were published in the European Society of Cardiology in August 2018, found the reduced intake of fibre and fruits in a low-carb diet and 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 Organisation 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.
Among those who ate the most fibre, the study found a 15% to 30% reduction in deaths from all causes, as well as those related to the heart, compared with those eating the least fibre.
The Mediterranean diet is also associated with a reduced incidence of cancer, 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 cancer.
Magan points out that the Mediterranean diet contains very little processed food. 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 said.
What seems to be at the forefront of all these studies, is the need for the inclusion of minimally processed fibrous foods in one’s diet.
Lifestyle adjustments, such as a healthy eating and exercise plan, can help kick-start a weight loss journey. Speak to your doctor about options or go to www.ilivelite.co.za for dietician-formulated, kilojoule-specific meal plans.