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Low carb diets significantly reduce HbA1c and medication compared to low fat diets

A study carried out in North Carolina, United States shows that low carbohydrate diets are more effective at both reducing HbA1c levels and of reducing the level of dependence on diabetes medication over a 1 year period in comparison with low fat diet interventions.
The researchers state that previous research has shown that low carbohydrate diets have been associated with a reduction in blood glucose levels but that previous research has not been able to quantify the effects as participants medication has had to be reduced to prevent increased risk of hypoglycemia and the level of reduction in diabetes medication has not been recorded as part of these previous studies.
In this study, the researchers assessed both HbA1c as well as the reduction in diabetes medication in both low carbohydrate and low fat diet groups. Medication was monitored through the study and reduced to prevent hypoglycemia and to aid weight loss. A medication effect score was used to quantify the reduction in medication over the course of the study. A medication score was used to take into account the fact that a number of significantly different medications can be used to treat type 2 diabetes.
The study included 46, mostly male, participants with type 2 diabetes. The participants had an average BMI of around 40, which is termed as extreme obesity. Participants HbA1c at the start of the trial was 60 mmol/mol (7.6%). The study ran for 48 weeks.
Participants were randomised into two diet groups, each of which aimed to achieve significant weight loss. The low carbohydrate diet group were instructed to have 20g of carbohydrate or less each day but calorie intake was not restricted. The low fat diet group were instructed to reduce fat intake to less than 30g per day and to restrict calories to between 500 and 1,000 kcal per day. The low fat group were also given the fat binding drug, Orlistat, in 120mg doses three times per day.
The results showed that both treatment groups were able to lose comparative amounts of weight. The low carb group lost 6.7% of their body weight over the 48 weeks whilst the low fat plus Orlistat group lost 7.3% of their body weight.
In terms of HbA1c, the low carb group saw a reduction of 8 mmol/mol (0.7%) whilst the low fat group, despite the weight loss, saw an increase of 1 mmol/mol (0.1%). In addition to reducing HbA1c, the low carb group also experienced a greater reduction in diabetes medication with 71% of participants able to reduce their medication effect score by 50% or more. By comparison, 30% of the low fat group experienced a 50% or more reduction of their medication effect score.
The effect on cholesterol showed that the reduction in total cholesterol and LDL (bad) cholesterol was better in the low fat group, whereas the reduction in triglyceride levels was stronger in the low carb group and a greater increase in HDL (good) cholesterol was experienced by the low carb dieters.
The study shows low carbohydrate diets to be effective in three key ways which can significantly improve long term health, those being: reduction in body weight, reduction in HbA1c and reduction in dependence on diabetes medication. By contrast, the low fat diet supplemented with Orlistat was only able to meet the reduction in body weight of these three factors.

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