The long term effects of low carb, higher fat diets have frequently been questioned but an eight year, randomised controlled study provides further evidence that low carb diets can be healthier than low fat ones for people with diabetes.
The study, carried out by researchers at The Second University of Naples compared the effects of two calorie restricted diets on participants with newly diagnosed type 2 diabetes. In both diets, participants kept to a 1,500 calorie intake for women and 1,800 calories for men.
Participants following the low carb Mediterranean diet were instructed to include plenty of vegetables, choose whole grain versions of starchy foods, replace most red meat with poultry and fish, and have at least 30% of their calories from fat, particularly from olive oil. The low fat dieters had less detailed instructions but were required to limit fatty and sugary foods and limit intake of fat to less than 30% of calorie intake.
The results showed that the higher fat group, the low carb Mediterranean dieters had better diabetes control shown by better HbA1c levels and much longer adherence to the diet.
The researchers also looked at how long the participants were able to live without needing diabetes medication. All low fat participants required medication after 6.1 years whereas it took 8.1 years before all the Mediterranean dieters required medication.
In terms of remission, that is patients being able to come off medication, this was again significantly more likely in the low carb Mediterranean diet group. Within the first year, 15% of the low carb group experienced partial or complete remission with only 5% of the low fat group achieving the same effect. Over 6 years, 4% of the low carb group achieved remission whereas none of the low fat group did.
Whilst previous research from epidemiological has shown that Mediterranean diets appear to be healthier than low fat diets, this long term, randomised controlled study provides more reliable evidence.
Whilst the research did not attempt to explore why the Mediterranean diet is healthier, the lower level of carbohydrates is likely to be significant as is the fact that the Mediterranean dieters were actively encouraged to have higher intake of vegetables.