Ketogenic diet beats low fat in study of patients with prediabetes and type 2 diabetes

A ketogenic diet showed significant success in losing weight, reducing HbA1c and reducing medication needs when compared with a low fat diet in a new 12-month study.
There is a lot of interest in ketogenic diets as a way to combat the weight gain and high blood sugar levels that have become so common in the modern world.
The study, run by researchers at the University of California, San Francisco, compared a very low carbohydrate, high fat ketogenic diet against a low fat, low calorie diet in 34 overweight adults. All participants selected had an HbA1c of over 42 mmol/mol (6%) at the start of the study, meaning they had either prediabetes or type 2 diabetes.
The participants on the keto diet were instructed to eat less 20-50 g of carbs per day and were instructed to achieve a blood ketone level of between 0.5-3 mmol/l when measured twice a week.
The participants on the low fat diet were instructed to have 45-50% of their calories coming from carbohydrate, to lower their fat intake and to eat 500 kcal less than their weight maintenance needs.
Both groups were encouraged to be physically active, get good sleep, and use behavioural strategies such as mindful eating.
The results showed that the keto group lost more weight (7.9 kg) than the low fat group did (1.7 kg). Furthermore, HbA1c reductions were greater on a keto diet. On keto, HbA1c reduced by 6 mmol/mol (0.5%) compared to 2 mmol/mol (0.2%) on low fat.
Six out of 10 of the keto group who were on diabetes medication were able to come off the medication. None of the six people on diabetes medication in the low fat group were able to stop theirs.
There were some interesting weight loss findings. Within the first six months, the keto group lost much more weight than the low fat group (6.1 kg compared to 1.7 kg). This is interesting because during the first six months, the low fat group recorded a lower calorie intake than the keto group (1,480 kcal compared with 1,590 kcal).
Another finding was that the low fat group found it harder to restrict calories by the 12-month mark. Calorie intake had risen to 1,680 kcal in the low fat group whilst the keto group were eating fewer calories (1,530 kcal) by the end of the study period.
These results show two things: lower calorie intake did not show better weight loss, and restricting carbohydrate intake appears to make it easier to stick to a lower energy intake long-term than trying to restrict fat intake.
Overall, the greater weight loss, lower HbA1c and reduced need for medication shows the ketogenic diet to be a stronger choice of diet than a low fat, low calorie diet that is currently favoured by the NHS.
The study is published online by the Nutrition &Diabetes journal.