I’d like to come back to the question of “what’s the best diet?” This week let’s look at a study that compared a low carbohydrate ketogenic diet vs. a low glycemic index diet. Take a look at the authors’ conclusion from this study (bold text mine):
“Dietary modification led to improvements in glycemic control and medication reduction/elimination in motivated volunteers with type 2 diabetes. The diet lower in carbohydrate led to greater improvements in glycemic control, and more frequent medication reduction/elimination than the low glycemic index diet. Lifestyle modification using low carbohydrate interventions is effective for improving and reversing type 2 diabetes.”
You might read this and conclude you need to follow a ketogenic diet, and that a low glycemic index diet is not good. But let’s dig a little bit.
It is true that participants in the ketogenic group lost more weight, had a bigger blood sugar drop, and were able to stop more diabetes medications than those in the low glycemic index group.
You might ask, so where’s the confusion?
I’d like to walk you through a few details of the study to shed a bit more light on the conclusions, and I hope give those of you who’ve tried keto and didn’t get results, or those who don’t want to eat keto, some hope.
In the study, the researchers randomized 97 people to one of the 2 diets:
Right out of the gate in this study, 10 people dropped out of the keto group and 3 out of the low glycemic index group. By the time the study finished, there were 21 left in the keto group and 29 in the low glycemic index group.
That means that the overall completion rate for all those randomized was 44% in the ketogenic group and 59% in the low glycemic index group. We’re not told why everyone dropped out, but at least 5 in the keto group and 3 in the low glycemic index group expressed dissatisfaction with the diet they were assigned.
Take Home Point #1 – Dropout rate was high
Next, take a look at this graph of the results of weight loss and blood sugar reduction (original here – I added the colored lines). The ketogenic diet participants are shown as the triangles and the low glycemic index participants as the squares.
Let’s look at how many people dropped their A1c by at least 2%. This will be all the people below the green line:
So, of the people who completed the study, more in the keto group dropped their A1c by at least 2%.
Now, how many people lost at least 20 pounds. This will be all the people to the left of the blue line (the scale on the graph is in kilograms):
Again, of the people who completed the study, more in the keto group lost at least 20 pounds.
Take Home Point #2 – A ketogenic diet can be quite powerful for those who can follow this diet over the long term
Take Home Point #3 – It is possible to get great results on either diet the program studied
What I hope you can see from this analysis is that study headlines don’t tell the whole story, and I’d recommend you be cautious when you’re told there is “one best way” for everyone. In this study only 44% of people assigned the ketogenic diet were willing and able to complete the 24-week study (and only 59% for the low glycemic index group).
Notice again that there were people who got excellent results in each group. We’re not given insight into how these folks were able to get superior results, what their characteristics, behaviors, or mindset was. I do think we could learn something from these people (or others in your life who have achieved what you are working toward) by modeling their actions.
If you try the “best way” and it works well for you, and you can sustain it long term, then you are on your way to success! But if you try the “best way” and it’s not getting you results, or you are miserable and don’t believe you’ll be able to stick with it, then by all means look for another way!
I believe this study reinforces 2 points that I like to teach, and I’ll end with these:
Have a great week.
Dr. Topher Fox