It’s Still All About the Calories
The keto vs. Mediterranean diet study was interesting for a variety of reasons. The researchers deserve a lot of credit for even attempting to try a study of this magnitude; 40 subjects may not seem like a lot, but to provide food via delivery together with instructions on preparation is very expensive and labor intensive. It should be noted that a portion of the study took place during the lockdown phase of COVID-19; that delayed some testing, but to their credit, the subjects affected continued the particular diet they were on for the two weeks until testing could be scheduled. Here are my thoughts on the results.
Blood Lipids
- Subjects on the keto diet showed a greater decrease in triglycerides (TG) than those on the Mediterranean diet.
- On the other hand, those on the Mediterranean showed a greater decrease in LDL-cholesterol than did the keto diet subjects.
While the researchers discussed it at length, I don’t think it was relevant. All subjects began with average fasting TG in the normal range. While both diets decreased TG, that the keto diet reduced it slightly more isn’t earth shattering when you start at a normal reading.
The same holds true for the LDL-cholesterol. Yes, the Mediterranean diet reduced it while the keto diet increased it, but the net was 6 mg/dl over the initial readings. What could have been concluded was that neither diet reduced LDL-cholesterol by an amount that was clinically meaningful.
The Microbiome
There were no tests of the changes in the microbiome under each diet reported—at least not yet. Subjects had a definite decline in fiber intake, especially when they provided their own food in the keto diet. The Mediterranean diet saw an increase in fiber intake when subjects provided their own food.
Why mention this at all? The microbiome controls the initial processing of nutrients. In addition, the immune function begins in the gut. While the keto diet may have provided some benefit related to HbA1c, at what cost? We simply don’t know. What we do know based on other research is that the lack of fiber changes the probiotic content of the microbiome.
The Bottom Line
The data showed that the subjects averaged 200 to 300 fewer calories per day regardless of diet and maintained the reduction over both diets. They ate better, they ate less, and they lost weight.
I think this study was important because it leaves us with better questions to ask in the future, such as: how would health measures be affected if subjects reduced calories another way? It also proves what I’ve been saying for years. The average weight loss after the study was 13 to 17 pounds, and that was maintained during the follow-up period. This was not a weight loss study, yet regardless of the initial diet, the subjects lost weight. I’ve said it before and I’ll say it again: regardless of the type of diet, it’s still all about the calories.
What are you prepared to do today?
Dr. Chet
Reference: AJCN doi.org/10.1093/ajcn/nqac154
