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Tuesday, 11 June 2013

Low carb diets and heart disease – What are we afraid of?

I find it extraordinary how carbohydrate restriction is repeatedly rejected by the medical community as an alternative approach for obesity, the metabolic syndrome and type 2 diabetes. Obesity has reached epidemic proportions in many countries around the world. Diabetes and other obesity related disorders have become increasingly common. Public health organizations and medical societies usually advocate a low-fat, high-carbohydrate, energy-deficient diet to manage weight. Nonetheless, clinical experience and scientific studies indicate that other approaches may be more effective.
The main argument against carbohydrate-restricted, high-fat diets are concerns regarding their long-term safety. Most such diets encourage increased consumption of animal products and therefore they often contain high amounts of saturated fat and cholesterol. It has been suggested that this may cause unfavorable changes in blood lipids and thereby increase the risk of heart disease. Therefore, several professional organizations have cautioned against the use of low-carbohydrate, high-fat diets.
According to a statement from the American Heart Association AHA, updated january 2012, “eating large amounts of high-fat foods for a sustained period raises the risk of coronary heart disease, diabetes, stroke and several types of cancer”. An older statement from the Heart and Stroke Foundation of Canada claims that ” low carbohydrate diets often lack vitamins and are low in fibre. A low fibre diet can result in constipation and can increase your risk of colon cancer. Low carbohydrate diets tend to replace carbohydrate with fat and protein. High intake of protein can result in large amounts of calcium in the urine, and loss of bone mass. High intake of fat, particularly saturated and trans fat, can lead to atherosclerosis, heart disease or stroke”.
These statements are based on observational data at best. Randomized clinical trials generally don´t support these conclusions. Indeed, low carbohydrate diets have demonstrated their therapeutic value in numerous studies, and often outperform other diets when comparisons are made. Nonetheless, they are still ignored by governments and medical societies. Keep in mind though, that carbohydrate restriction is a matter of definition. Some diabetic associations have accepted moderate carbohydrate restriction as an alternative approach for weight loss in type 2 diabetes.
Doctors, cardiologists included, commonly recommend low-fat, high-carbohydrate diets to patients with heart disease, as well as for cardiovascular prevention. Limitation of saturated fats and cholesterol is advocated. This is what doctors are urged to do by clinical guidelines. The guidelines are written by specially selected experts and published by professional organizations. Interestingly, there is often no mention of individual differences between patients. The low-fat, low saturated fat, low cholesterol, high-carbohydrate approach is recommended for all. It doesn´t matter whether you have high blood pressure, whether you are obese or overweight, have the metabolic syndrome, or whether you have diabetes.
I have nothing against low fat diets. Look at the DASH diet for example. Extensive research indicates that this diet lowers lood pressure and cholesterol, and is associated with lower risk of several diseases, including heart disease. Furthermore, it was recently suggested that the DASH diet may be used for weight loss as well. I would be very satisfied if may patients would stick to the DASH diet. I usually urge them to do so. I am sure it benefits their health. The same thing can be said about a vegetarian diet. I consider such a diet to be a very heart healthy diet. Furthermore, I very often recommend a Mediterranean type diet to my patients. There is a lot of scientific date supporting the use of this diet for cardiovascular prevention as well as for patients with heart disease.
The role of diets takes on a different perspective when it comes to obese patients, and those with the metabolic syndrome, where weight loss is a priority. For years I have struggled with the low-fat, high-carbohydrate, energy-deficient dietary approach to manage these conditions. Simply put, the results have been disappointing. Often weight loss is limited and not sustained, and there are very limited improvements in metabolic function. However, I might admit the lack of result is more often due to lack of compliance than something else. Maybe we provide instructions and recommendations that patients are unable to comply with, no matter how hard they try.
Graham

4 comments:

Anonymous said...

Thanks, an extremely interesting read,I felt I also wanted to put this up for people to see. It comes near the end of the document, you owe it to yourself to read it through.

"I look forward to the day when low-carb, high-fat diets are accepted by public health representatives and medical associations for the treatment of obesity, metabolic syndrome and type 2 diabetes. The medical community, which I am a part of, accepts that drugs that lower cholesterol, and slightly reduce the risk of heart disease (although having considerable side effects, among them increased risk of diabetes) are given to 25 percent of adults in many countries around the world. I find it a bit hard to accept that the same medical community does not accept and recommend a dietary approach for obesity and the metabolic syndrome, that causes weight loss, increases wellbeing and improves metabolic function, and indeed appears to outperform other diets in this respect."

Kay

Lowcarb team member said...

Thanks for your comment Kay, I would have put the entire post up but unfortunately it was a bit to long.

Cheers
Graham


Anonymous said...

Great piece this
Josh

Anonymous said...

Very good article to read, thanks Graham

Paul B