A new study suggests that low carbohydrate diets are unsafe and should be avoided1 while another landmark study has concluded that high fibre cuts heart disease risk2.
Low carbohydrate diets have been popular for decades, and come with their own scientific backing3
So what now?
We asked two local specialists for their take on the low carb diet.
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 beneficial4. “…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 says4.
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 and even drinking red wine in moderation5.
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 oxidized low-density lipoprotein (LDL) cholesterol — the “bad” cholesterol that’s more likely to build up deposits in your arteries5.
Dr Rosetta Guidozzi, a General Practitioner from Johannesburg, says that essentially 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 example6.
“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,” Dr Guidozzi explains. “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 that which is responsible for Cardiovascular disease,” she says6.
“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 says6.
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 says6.
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 disease, cerebrovascular disease, and cancer1.
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 phytochemicals1.
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 death2.
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 fibre2.
This report said 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 lives2.
The much revered 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 organizations 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 food4.
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 says6.
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 diet2.
Speak to your doctor about weight loss management options that might be best for you. Go to www.ilivelite.co.za for more information.
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References: 1. Science Daily. Low carbohydrate diets are unsafe and should be avoided, study suggests (2018) at https://www.sciencedaily.com/releases/2018/08/180828085922.htm. 2. The Guardian. Blow to low carb diet as landmark study finds high fibre cuts heart disease risk (2019) at https://www.theguardian.com/lifeandstyle/2019/jan/10/high-fibre-diets-cut-heart-disease-risk-landmark-study-finds?CMP=share_btn_fb&fbclid=IwAR1QiZugsR99qHhtRhh7yF5AeDe8eC5tzLJqbNYPT8k7rjnPW0mQN7FRC2o. 3. 9 Myths about Low Carb Diets (2015) at https://www.healthline.com/nutrition/9-myths-about-low-carb-diets. 4. Information from Dr A Magan January 2019 (unpaid). 5. Mayo Clinic – Mediterranean diet: A heart-healthy eating plan (2019) at https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/mediterranean-diet/art-20047801. 6. Information from Dr R Guidozzi February 2019 (unpaid). 7. Phelan S, Wadden TA. Combining Behavioural and Pharmacological Treatments for Obesity. Obes Res 2002;10(6):560-574