Some people are reluctant to try a low carbohydrate, high fat diet as we have heard for decades that a high fat diet will cause heart disease. This is based on the so called "lipid hypothesis" which, when scrutinized, appears to have been based on very biased studies. It does, however, appear that low triglycerides, low lipoprotein(a), low insulin resistance, and high HDL are all associated with reduced cardiovascular risk.
A recent study: "Effects of a low-carbohydrate diet on insulin- resistant dyslipoproteinemia- a randomized controlled feeding trial," is an excellent example of how good nutritional research should be performed. Unlike most nutritional studies, it does not rely on food surveys, which are notoriously inaccurate. It is an actual interventional study.
3 groups of patients were randomized. All of their meals were prepared by the study administrators. All groups had the same 20% protein content. After an initial 10-14% weight loss which was achieved on the same run-in diet, the groups were then stratified into low-carb (20%), moderate-carb (40%), and high-carb (60%) meals. The low carb group ate 21% saturated fat, moderate carb 14% saturated fat, and low carb 7% saturated fat.
Lipid markers associated with cardiovascular risk were tested at baseline and then at 20 weeks.
The lipid hypothesis would predict the low carb/high saturated fat group would experience elevated cardiovascular risk.
What was actually found?
Exactly the opposite. The low-carbohydrate, high-fat group experienced improvement in insulin resistance, improvement in triglyceride levels, reduced lipoprotein(a), and increased HDL and adiponectin. These all indicate improved cardiovascular risk.
So- now we have a very well done nutritional study which suggests doing the opposite of the traditionally recommended diet (food pyramid) appears to improve cardiovascular risk factors.
I hope we will continue to see nutritional studies performed that are as well designed as this one.