The Duke University Lifestyle Medicine Clinic prescribes a nutritional program based upon a very simple concept, limit carbohydrate intake and multiple problems improve. This approach is so powerful in controlling blood sugar that diabetic patients must reduce their medication before adopting the nutritional program in order to avoid very low blood sugars.
Compared to a low-fat diet weight loss approach, it is better or equal on every measurement studied. Here is what happens on the carbohydrate restricted program when compared to a low fat diet (American Heart Association diet). The carbohydrate restricted diet results in
- Greater reduction in weight and body fat
- Greater reduction in fasting blood sugar
- Reduction in the amount of saturated fat circulating in the blood despite a higher intake than a low fat diet
- Greater reduction in insulin with improved insulin sensitivity
- Reduction in small LDL (low fat diets increase small LDL which is considered to be associated with more heart attacks and strokes)
- Increase in HDL (low fat diets decrease HDL, decreased HDL is associated with increased risk of heart attack and stroke)
- Greater reduction in Triglycerides
- Reduction in the ApoB/ApoA-1 ratio (low fat diets do the opposite, and the opposite is considered to increase risk of heart attack and stroke).
- Reduction in multiple markers of inflammation
- Spontaneous reduction in caloric consumption without counting or restricting calories (people automatically eat less as a result of restricting carbohydrates, low-fat diets require counting and restricting calories in order to lose weight)
- Increased consumption of non-starchy vegetables
All of these beneficial effects are accepted by the medical community as reducing cardiovascular risk .
The improved metabolic outcome can occur even without weight loss simply by substituting fat for carbohydrate.
“The key principle is that carbohydrate, directly or indirectly through the effect of insulin, controls the disposition of excess dietary nutrients. Dietary carbohydrate modulates lipolysis, lipoprotein assembly and processing and affects the relation between dietary intake of saturated fat intake and circulating levels.” see here
Yet despite these proven effects, the proponents of low-fat diets refer to the carbohydrate restriction approach as a “fad diet”. In his excellent discussion of this term, Richard Feinman points out that historically, a carbohydrate restriction approach is actually the longest standing and proven approach to the treatment of obesity compared to a low-fat diet which is a relative newcomer. He describes how a low-fat diet more closely meets the dictionary’s definition of a “fad”.
Multiple Studies have compared carbohydrate restriction to low fat diet approaches and the results are consistent. In addition to the advantages cited above, carbohydrate restricted approaches when compared to low-fat diets reveal that symptoms of “negative affect and hunger improved to a greater degree” compared with those following a low fat diet”. (see here)
When one analyzes the carbohydrate restricted diet (CRD) approach employed by many centers, including the Duke Interventional Medicine Clinic, one finds great similarity to a paleolithic diet.
They both eliminate or dramatically reduce
- sugar-sweetened foods and beverages,
- grains, flour foods and cereal foods
- legumes (paleo completely, CRD to a large extent)
- processed-refined vegetable oils
- dairy (paleo completely, CRD to a large extent)
Fruits under a CRD are limited to small amounts of berries initially and this is liberalized over time as weight loss is achieved and metabolic parameters are improved. This is consistent with a paleolithic approach that recognizes that fruits and vegetables grown today have been bred to provide much higher sugar and starch content compared to the pre-agricultural fruits and vegetables that early hominids consumed for hundreds of thousands of years.
A carbohydrate restricted nutritional approach to treat obesity, diabetes, or metabolic syndrome appears to be a valid and arguably superior remedy to a growing problem in the developed world. Yet despite this strong and convincing scientific data, dietary fat-phobia has impaired the utilization of this proven therapeutic modality.
Bob Hansen M.D.