This is a study that came out in February of this year, that I found because I am reading the The Ketogenic Bible: The Authoritative Guide to Ketosis and this reference popped up in a discussion of the impact on lipids of a low-carbohydrate diet.
The study itself is a small randomized trial (total of 25 people) of using online behavioral interventions for two types of diets – a very low carbohydrate one and a more “standard” American Diabetic Association diet, conducted over 32 weeks.The endpoint was HbA1c.
As I’ve mentioned previously, it’s now impossible to interpret a study in nutrition without examining potential conflicts as well as the twitter reaction to see what the “sides” are. In this case, one of the authors is on the Scientific Advisory Board of Virta Health (@virtahealth) and the lead author has done prior work with leaders in nutritional ketosis, so if there was bias, it would be toward the low-carbohydrate diet.
The interesting things to me here are
- Effectiveness of an online intervention. A LOT of what I have read in this space has shown that online doesn’t really work that well at all without an in person component (see: Just Read: Current Science on Consumer Use of Mobile Health for Cardiovascular Disease Prevention)
- It appears in this study, than an online intervention showed effectiveness, with caveats
- Caveat: Pretty significant dropout rate in the control (ADA diet) group
- Caveat: The control (ADA diet) group did not get the same intervention, specifically about mindfulness and other behavioral techniques
Triglyceride drop
Taking a look at the lipid changes (not a primary endpoint) shows a significant drop in triglycerides, without significant changes in HDL or LDL. There is much discussion about how low-carbohydrate diets (which are also higher-fat ones if protein is kept constant) can raise LDL and HDL, with an overall net improvement in lipid profile. Here, it’s just the triglyceride drop, in a setting where people have been instructed to increase the percentage of fat in their diets.
Watch the triglycerides.
No one-size-fits-all
There are a lot of explanations for how these changes might happen, which are too long for this blog post. The study alludes to the fact that the low fat diet is based on restriction of portion size (caloric intake) with foods that are less satiating, compared to the low-carbohydrate diet with no restriction on how much or how many calories, so even if the two diets are equal from a biochemical point of view (they probably are not), you get the sense that one is more painful to engage in than another. We probably can’t continue to ignore that situation if we’re going to be successful in promoting health. It’s highly possible that the people advertising low fat diets in the commercial below are really not as happy as they seemed….
Cite: Saslow LR, Mason AE, Kim S, Goldman V, Ploutz-Snyder R, Bayandorian H, et al. An Online Intervention Comparing a Very Low-Carbohydrate Ketogenic Diet and Lifestyle Recommendations Versus a Plate Method Diet in Overweight Individuals With Type 2 Diabetes: A Randomized Controlled Trial. J Med Internet Res [Internet]. 2017 Feb 13;19(2):e36. Available from: http://www.jmir.org/2017/2/e36/